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2023-02-20Merge tag 'fs.idmapped.v6.3' of ↵Linus Torvalds1-65/+64
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping Pull vfs idmapping updates from Christian Brauner: - Last cycle we introduced the dedicated struct mnt_idmap type for mount idmapping and the required infrastucture in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). As promised in last cycle's pull request message this converts everything to rely on struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevant on the mount level. Especially for non-vfs developers without detailed knowledge in this area this was a potential source for bugs. This finishes the conversion. Instead of passing the plain namespace around this updates all places that currently take a pointer to a mnt_userns with a pointer to struct mnt_idmap. Now that the conversion is done all helpers down to the really low-level helpers only accept a struct mnt_idmap argument instead of two namespace arguments. Conflating mount and other idmappings will now cause the compiler to complain loudly thus eliminating the possibility of any bugs. This makes it impossible for filesystem developers to mix up mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. Everything associated with struct mnt_idmap is moved into a single separate file. With that change no code can poke around in struct mnt_idmap. It can only be interacted with through dedicated helpers. That means all filesystems are and all of the vfs is completely oblivious to the actual implementation of idmappings. We are now also able to extend struct mnt_idmap as we see fit. For example, we can decouple it completely from namespaces for users that don't require or don't want to use them at all. We can also extend the concept of idmappings so we can cover filesystem specific requirements. In combination with the vfs{g,u}id_t work we finished in v6.2 this makes this feature substantially more robust and thus difficult to implement wrong by a given filesystem and also protects the vfs. - Enable idmapped mounts for tmpfs and fulfill a longstanding request. A long-standing request from users had been to make it possible to create idmapped mounts for tmpfs. For example, to share the host's tmpfs mount between multiple sandboxes. This is a prerequisite for some advanced Kubernetes cases. Systemd also has a range of use-cases to increase service isolation. And there are more users of this. However, with all of the other work going on this was way down on the priority list but luckily someone other than ourselves picked this up. As usual the patch is tiny as all the infrastructure work had been done multiple kernel releases ago. In addition to all the tests that we already have I requested that Rodrigo add a dedicated tmpfs testsuite for idmapped mounts to xfstests. It is to be included into xfstests during the v6.3 development cycle. This should add a slew of additional tests. * tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits) shmem: support idmapped mounts for tmpfs fs: move mnt_idmap fs: port vfs{g,u}id helpers to mnt_idmap fs: port fs{g,u}id helpers to mnt_idmap fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap fs: port i_{g,u}id_{needs_}update() to mnt_idmap quota: port to mnt_idmap fs: port privilege checking helpers to mnt_idmap fs: port inode_owner_or_capable() to mnt_idmap fs: port inode_init_owner() to mnt_idmap fs: port acl to mnt_idmap fs: port xattr to mnt_idmap fs: port ->permission() to pass mnt_idmap fs: port ->fileattr_set() to pass mnt_idmap fs: port ->set_acl() to pass mnt_idmap fs: port ->get_acl() to pass mnt_idmap fs: port ->tmpfile() to pass mnt_idmap fs: port ->rename() to pass mnt_idmap fs: port ->mknod() to pass mnt_idmap fs: port ->mkdir() to pass mnt_idmap ...
2023-01-19fs: port vfs{g,u}id helpers to mnt_idmapChristian Brauner1-3/+2
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmapChristian Brauner1-16/+8
Convert to struct mnt_idmap. Remove legacy file_mnt_user_ns() and mnt_user_ns(). Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port i_{g,u}id_{needs_}update() to mnt_idmapChristian Brauner1-2/+2
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port privilege checking helpers to mnt_idmapChristian Brauner1-24/+29
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port inode_owner_or_capable() to mnt_idmapChristian Brauner1-4/+3
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port xattr to mnt_idmapChristian Brauner1-2/+2
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->permission() to pass mnt_idmapChristian Brauner1-3/+4
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->setattr() to pass mnt_idmapChristian Brauner1-15/+17
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-18fs: port vfs_*() helpers to struct mnt_idmapChristian Brauner1-6/+7
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-11filelock: move file locking definitions to separate header fileJeff Layton1-0/+1
The file locking definitions have lived in fs.h since the dawn of time, but they are only used by a small subset of the source files that include it. Move the file locking definitions to a new header file, and add the appropriate #include directives to the source files that need them. By doing this we trim down fs.h a bit and limit the amount of rebuilding that has to be done when we make changes to the file locking APIs. Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Acked-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Acked-by: Steve French <stfrench@microsoft.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-10-18attr: use consistent sgid stripping checksChristian Brauner1-14/+19
Currently setgid stripping in file_remove_privs()'s should_remove_suid() helper is inconsistent with other parts of the vfs. Specifically, it only raises ATTR_KILL_SGID if the inode is S_ISGID and S_IXGRP but not if the inode isn't in the caller's groups and the caller isn't privileged over the inode although we require this already in setattr_prepare() and setattr_copy() and so all filesystem implement this requirement implicitly because they have to use setattr_{prepare,copy}() anyway. But the inconsistency shows up in setgid stripping bugs for overlayfs in xfstests (e.g., generic/673, generic/683, generic/685, generic/686, generic/687). For example, we test whether suid and setgid stripping works correctly when performing various write-like operations as an unprivileged user (fallocate, reflink, write, etc.): echo "Test 1 - qa_user, non-exec file $verb" setup_testfile chmod a+rws $junk_file commit_and_check "$qa_user" "$verb" 64k 64k The test basically creates a file with 6666 permissions. While the file has the S_ISUID and S_ISGID bits set it does not have the S_IXGRP set. On a regular filesystem like xfs what will happen is: sys_fallocate() -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> setattr_copy() In should_remove_suid() we can see that ATTR_KILL_SUID is raised unconditionally because the file in the test has S_ISUID set. But we also see that ATTR_KILL_SGID won't be set because while the file is S_ISGID it is not S_IXGRP (see above) which is a condition for ATTR_KILL_SGID being raised. So by the time we call notify_change() we have attr->ia_valid set to ATTR_KILL_SUID | ATTR_FORCE. Now notify_change() sees that ATTR_KILL_SUID is set and does: ia_valid = attr->ia_valid |= ATTR_MODE attr->ia_mode = (inode->i_mode & ~S_ISUID); which means that when we call setattr_copy() later we will definitely update inode->i_mode. Note that attr->ia_mode still contains S_ISGID. Now we call into the filesystem's ->setattr() inode operation which will end up calling setattr_copy(). Since ATTR_MODE is set we will hit: if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode); if (!vfsgid_in_group_p(vfsgid) && !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) mode &= ~S_ISGID; inode->i_mode = mode; } and since the caller in the test is neither capable nor in the group of the inode the S_ISGID bit is stripped. But assume the file isn't suid then ATTR_KILL_SUID won't be raised which has the consequence that neither the setgid nor the suid bits are stripped even though it should be stripped because the inode isn't in the caller's groups and the caller isn't privileged over the inode. If overlayfs is in the mix things become a bit more complicated and the bug shows up more clearly. When e.g., ovl_setattr() is hit from ovl_fallocate()'s call to file_remove_privs() then ATTR_KILL_SUID and ATTR_KILL_SGID might be raised but because the check in notify_change() is questioning the ATTR_KILL_SGID flag again by requiring S_IXGRP for it to be stripped the S_ISGID bit isn't removed even though it should be stripped: sys_fallocate() -> vfs_fallocate() -> ovl_fallocate() -> file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> ovl_setattr() // TAKE ON MOUNTER'S CREDS -> ovl_do_notify_change() -> notify_change() // GIVE UP MOUNTER'S CREDS // TAKE ON MOUNTER'S CREDS -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = attr_force | kill; -> notify_change() The fix for all of this is to make file_remove_privs()'s should_remove_suid() helper to perform the same checks as we already require in setattr_prepare() and setattr_copy() and have notify_change() not pointlessly requiring S_IXGRP again. It doesn't make any sense in the first place because the caller must calculate the flags via should_remove_suid() anyway which would raise ATTR_KILL_SGID. While we're at it we move should_remove_suid() from inode.c to attr.c where it belongs with the rest of the iattr helpers. Especially since it returns ATTR_KILL_S{G,U}ID flags. We also rename it to setattr_should_drop_suidgid() to better reflect that it indicates both setuid and setgid bit removal and also that it returns attr flags. Running xfstests with this doesn't report any regressions. We should really try and use consistent checks. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-18attr: add setattr_should_drop_sgid()Christian Brauner1-0/+28
The current setgid stripping logic during write and ownership change operations is inconsistent and strewn over multiple places. In order to consolidate it and make more consistent we'll add a new helper setattr_should_drop_sgid(). The function retains the old behavior where we remove the S_ISGID bit unconditionally when S_IXGRP is set but also when it isn't set and the caller is neither in the group of the inode nor privileged over the inode. We will use this helper both in write operation permission removal such as file_remove_privs() as well as in ownership change operations. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-18fs: move should_remove_suid()Christian Brauner1-0/+29
Move the helper from inode.c to attr.c. This keeps the the core of the set{g,u}id stripping logic in one place when we add follow-up changes. It is the better place anyway, since should_remove_suid() returns ATTR_KILL_S{G,U}ID flags. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-18attr: add in_group_or_capable()Christian Brauner1-5/+5
In setattr_{copy,prepare}() we need to perform the same permission checks to determine whether we need to drop the setgid bit or not. Instead of open-coding it twice add a simple helper the encapsulates the logic. We will reuse this helpers to make dropping the setgid bit during write operations more consistent in a follow up patch. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-08-08vfs: Check the truncate maximum size in inode_newsize_ok()David Howells1-0/+2
If something manages to set the maximum file size to MAX_OFFSET+1, this can cause the xfs and ext4 filesystems at least to become corrupt. Ordinarily, the kernel protects against userspace trying this by checking the value early in the truncate() and ftruncate() system calls calls - but there are at least two places that this check is bypassed: (1) Cachefiles will round up the EOF of the backing file to DIO block size so as to allow DIO on the final block - but this might push the offset negative. It then calls notify_change(), but this inadvertently bypasses the checking. This can be triggered if someone puts an 8EiB-1 file on a server for someone else to try and access by, say, nfs. (2) ksmbd doesn't check the value it is given in set_end_of_file_info() and then calls vfs_truncate() directly - which also bypasses the check. In both cases, it is potentially possible for a network filesystem to cause a disk filesystem to be corrupted: cachefiles in the client's cache filesystem; ksmbd in the server's filesystem. nfsd is okay as it checks the value, but we can then remove this check too. Fix this by adding a check to inode_newsize_ok(), as called from setattr_prepare(), thereby catching the issue as filesystems set up to perform the truncate with minimal opportunity for bypassing the new check. Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling") Fixes: f44158485826 ("cifsd: add file operations") Signed-off-by: David Howells <dhowells@redhat.com> Reported-by: Jeff Layton <jlayton@kernel.org> Tested-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Namjae Jeon <linkinjeon@kernel.org> Cc: stable@kernel.org Acked-by: Alexander Viro <viro@zeniv.linux.org.uk> cc: Steve French <sfrench@samba.org> cc: Hyunchul Lee <hyc.lee@gmail.com> cc: Chuck Lever <chuck.lever@oracle.com> cc: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-06-27attr: fix kernel docChristian Brauner1-2/+2
When building kernel documentation new warnings were generated because the name in the parameter documentation didn't match the parameter name. Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-06-26attr: port attribute changes to new typesChristian Brauner1-36/+32
Now that we introduced new infrastructure to increase the type safety for filesystems supporting idmapped mounts port the first part of the vfs over to them. This ports the attribute changes codepaths to rely on the new better helpers using a dedicated type. Before this change we used to take a shortcut and place the actual values that would be written to inode->i_{g,u}id into struct iattr. This had the advantage that we moved idmappings mostly out of the picture early on but it made reasoning about changes more difficult than it should be. The filesystem was never explicitly told that it dealt with an idmapped mount. The transition to the value that needed to be stored in inode->i_{g,u}id appeared way too early and increased the probability of bugs in various codepaths. We know place the same value in struct iattr no matter if this is an idmapped mount or not. The vfs will only deal with type safe vfs{g,u}id_t. This makes it massively safer to perform permission checks as the type will tell us what checks we need to perform and what helpers we need to use. Fileystems raising FS_ALLOW_IDMAP can't simply write ia_vfs{g,u}id to inode->i_{g,u}id since they are different types. Instead they need to use the dedicated vfs{g,u}id_to_k{g,u}id() helpers that map the vfs{g,u}id into the filesystem. The other nice effect is that filesystems like overlayfs don't need to care about idmappings explicitly anymore and can simply set up struct iattr accordingly directly. Link: https://lore.kernel.org/lkml/CAHk-=win6+ahs1EwLkcq8apqLi_1wXFWbrPf340zYEhObpz4jA@mail.gmail.com [1] Link: https://lore.kernel.org/r/20220621141454.2914719-9-brauner@kernel.org Cc: Seth Forshee <sforshee@digitalocean.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-06-26security: pass down mount idmapping to setattr hookChristian Brauner1-1/+1
Before this change we used to take a shortcut and place the actual values that would be written to inode->i_{g,u}id into struct iattr. This had the advantage that we moved idmappings mostly out of the picture early on but it made reasoning about changes more difficult than it should be. The filesystem was never explicitly told that it dealt with an idmapped mount. The transition to the value that needed to be stored in inode->i_{g,u}id appeared way too early and increased the probability of bugs in various codepaths. We know place the same value in struct iattr no matter if this is an idmapped mount or not. The vfs will only deal with type safe vfs{g,u}id_t. This makes it massively safer to perform permission checks as the type will tell us what checks we need to perform and what helpers we need to use. Adapt the security_inode_setattr() helper to pass down the mount's idmapping to account for that change. Link: https://lore.kernel.org/r/20220621141454.2914719-8-brauner@kernel.org Cc: Seth Forshee <sforshee@digitalocean.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-06-26fs: port to iattr ownership update helpersChristian Brauner1-4/+2
Earlier we introduced new helpers to abstract ownership update and remove code duplication. This converts all filesystems supporting idmapped mounts to make use of these new helpers. For now we always pass the initial idmapping which makes the idmapping functions these helpers call nops. This is done because we currently always pass the actual value to be written to i_{g,u}id via struct iattr. While this allowed us to treat the {g,u}id values in struct iattr as values that can be directly written to inode->i_{g,u}id it also increases the potential for confusion for filesystems. Now that we are have dedicated types to prevent this confusion we will ultimately only map the value from the idmapped mount into a filesystem value that can be written to inode->i_{g,u}id when the filesystem actually updates the inode. So pass down the initial idmapping until we finished that conversion at which point we pass down the mount's idmapping. No functional changes intended. Link: https://lore.kernel.org/r/20220621141454.2914719-6-brauner@kernel.org Cc: Seth Forshee <sforshee@digitalocean.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-06-14fs: account for group membershipChristian Brauner1-6/+20
When calling setattr_prepare() to determine the validity of the attributes the ia_{g,u}id fields contain the value that will be written to inode->i_{g,u}id. This is exactly the same for idmapped and non-idmapped mounts and allows callers to pass in the values they want to see written to inode->i_{g,u}id. When group ownership is changed a caller whose fsuid owns the inode can change the group of the inode to any group they are a member of. When searching through the caller's groups we need to use the gid mapped according to the idmapped mount otherwise we will fail to change ownership for unprivileged users. Consider a caller running with fsuid and fsgid 1000 using an idmapped mount that maps id 65534 to 1000 and 65535 to 1001. Consequently, a file owned by 65534:65535 in the filesystem will be owned by 1000:1001 in the idmapped mount. The caller now requests the gid of the file to be changed to 1000 going through the idmapped mount. In the vfs we will immediately map the requested gid to the value that will need to be written to inode->i_gid and place it in attr->ia_gid. Since this idmapped mount maps 65534 to 1000 we place 65534 in attr->ia_gid. When we check whether the caller is allowed to change group ownership we first validate that their fsuid matches the inode's uid. The inode->i_uid is 65534 which is mapped to uid 1000 in the idmapped mount. Since the caller's fsuid is 1000 we pass the check. We now check whether the caller is allowed to change inode->i_gid to the requested gid by calling in_group_p(). This will compare the passed in gid to the caller's fsgid and search the caller's additional groups. Since we're dealing with an idmapped mount we need to pass in the gid mapped according to the idmapped mount. This is akin to checking whether a caller is privileged over the future group the inode is owned by. And that needs to take the idmapped mount into account. Note, all helpers are nops without idmapped mounts. New regression test sent to xfstests. Link: https://github.com/lxc/lxd/issues/10537 Link: https://lore.kernel.org/r/20220613111517.2186646-1-brauner@kernel.org Fixes: 2f221d6f7b88 ("attr: handle idmapped mounts") Cc: Seth Forshee <sforshee@digitalocean.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org # 5.15+ CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2021-11-17fs: handle circular mappings correctlyChristian Brauner1-2/+2
When calling setattr_prepare() to determine the validity of the attributes the ia_{g,u}id fields contain the value that will be written to inode->i_{g,u}id. When the {g,u}id attribute of the file isn't altered and the caller's fs{g,u}id matches the current {g,u}id attribute the attribute change is allowed. The value in ia_{g,u}id does already account for idmapped mounts and will have taken the relevant idmapping into account. So in order to verify that the {g,u}id attribute isn't changed we simple need to compare the ia_{g,u}id value against the inode's i_{g,u}id value. This only has any meaning for idmapped mounts as idmapping helpers are idempotent without them. And for idmapped mounts this really only has a meaning when circular idmappings are used, i.e. mappings where e.g. id 1000 is mapped to id 1001 and id 1001 is mapped to id 1000. Such ciruclar mappings can e.g. be useful when sharing the same home directory between multiple users at the same time. As an example consider a directory with two files: /source/file1 owned by {g,u}id 1000 and /source/file2 owned by {g,u}id 1001. Assume we create an idmapped mount at /target with an idmapping that maps files owned by {g,u}id 1000 to being owned by {g,u}id 1001 and files owned by {g,u}id 1001 to being owned by {g,u}id 1000. In effect, the idmapped mount at /target switches the ownership of /source/file1 and source/file2, i.e. /target/file1 will be owned by {g,u}id 1001 and /target/file2 will be owned by {g,u}id 1000. This means that a user with fs{g,u}id 1000 must be allowed to setattr /target/file2 from {g,u}id 1000 to {g,u}id 1000. Similar, a user with fs{g,u}id 1001 must be allowed to setattr /target/file1 from {g,u}id 1001 to {g,u}id 1001. Conversely, a user with fs{g,u}id 1000 must fail to setattr /target/file1 from {g,u}id 1001 to {g,u}id 1000. And a user with fs{g,u}id 1001 must fail to setattr /target/file2 from {g,u}id 1000 to {g,u}id 1000. Both cases must fail with EPERM for non-capable callers. Before this patch we could end up denying legitimate attribute changes and allowing invalid attribute changes when circular mappings are used. To even get into this situation the caller must've been privileged both to create that mapping and to create that idmapped mount. This hasn't been seen in the wild anywhere but came up when expanding the testsuite during work on a series of hardening patches. All idmapped fstests pass without any regressions and we add new tests to verify the behavior of circular mappings. Link: https://lore.kernel.org/r/20211109145713.1868404-1-brauner@kernel.org Fixes: 2f221d6f7b88 ("attr: handle idmapped mounts") Cc: Seth Forshee <seth.forshee@digitalocean.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org CC: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-08-13fs: Move notify_change permission checks into may_setattrAndreas Gruenbacher1-19/+31
Move the permission checks in notify_change into a separate function to make them available to filesystems. When notify_change is called, the vfs performs those checks before calling into iop->setattr. However, a filesystem like gfs2 can only lock and revalidate the inode inside ->setattr, and it must then repeat those checks to err on the safe side. It would be nice to get rid of the double checking, but moving the permission check into iop->setattr altogether isn't really an option. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-01-24ima: handle idmapped mountsChristian Brauner1-1/+1
IMA does sometimes access the inode's i_uid and compares it against the rules' fowner. Enable IMA to handle idmapped mounts by passing down the mount's user namespace. We simply make use of the helpers we introduced before. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-27-christian.brauner@ubuntu.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24fs: make helpers idmap mount awareChristian Brauner1-2/+2
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24commoncap: handle idmapped mountsChristian Brauner1-1/+1
When interacting with user namespace and non-user namespace aware filesystem capabilities the vfs will perform various security checks to determine whether or not the filesystem capabilities can be used by the caller, whether they need to be removed and so on. The main infrastructure for this resides in the capability codepaths but they are called through the LSM security infrastructure even though they are not technically an LSM or optional. This extends the existing security hooks security_inode_removexattr(), security_inode_killpriv(), security_inode_getsecurity() to pass down the mount's user namespace and makes them aware of idmapped mounts. In order to actually get filesystem capabilities from disk the capability infrastructure exposes the get_vfs_caps_from_disk() helper. For user namespace aware filesystem capabilities a root uid is stored alongside the capabilities. In order to determine whether the caller can make use of the filesystem capability or whether it needs to be ignored it is translated according to the superblock's user namespace. If it can be translated to uid 0 according to that id mapping the caller can use the filesystem capabilities stored on disk. If we are accessing the inode that holds the filesystem capabilities through an idmapped mount we map the root uid according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts: reading filesystem caps from disk enforces that the root uid associated with the filesystem capability must have a mapping in the superblock's user namespace and that the caller is either in the same user namespace or is a descendant of the superblock's user namespace. For filesystems that are mountable inside user namespace the caller can just mount the filesystem and won't usually need to idmap it. If they do want to idmap it they can create an idmapped mount and mark it with a user namespace they created and which is thus a descendant of s_user_ns. For filesystems that are not mountable inside user namespaces the descendant rule is trivially true because the s_user_ns will be the initial user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24attr: handle idmapped mountsChristian Brauner1-29/+90
When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24inode: make init and permission helpers idmapped mount awareChristian Brauner1-3/+3
The inode_owner_or_capable() helper determines whether the caller is the owner of the inode or is capable with respect to that inode. Allow it to handle idmapped mounts. If the inode is accessed through an idmapped mount it according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Similarly, allow the inode_init_owner() helper to handle idmapped mounts. It initializes a new inode on idmapped mounts by mapping the fsuid and fsgid of the caller from the mount's user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24namei: make permission helpers idmapped mount awareChristian Brauner1-1/+2
The two helpers inode_permission() and generic_permission() are used by the vfs to perform basic permission checking by verifying that the caller is privileged over an inode. In order to handle idmapped mounts we extend the two helpers with an additional user namespace argument. On idmapped mounts the two helpers will make sure to map the inode according to the mount's user namespace and then peform identical permission checks to inode_permission() and generic_permission(). If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24capability: handle idmapped mountsChristian Brauner1-4/+4
In order to determine whether a caller holds privilege over a given inode the capability framework exposes the two helpers privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former verifies that the inode has a mapping in the caller's user namespace and the latter additionally verifies that the caller has the requested capability in their current user namespace. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped inodes. If the initial user namespace is passed all operations are a nop so non-idmapped mounts will not see a change in behavior. Link: https://lore.kernel.org/r/20210121131959.646623-5-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-12-09utimes: Clamp the timestamps in notify_change()Amir Goldstein1-12/+11
Push clamping timestamps into notify_change(), so in-kernel callers like nfsd and overlayfs will get similar timestamp set behavior as utimes. AV: get rid of clamping in ->setattr() instances; we don't need to bother with that there, with notify_change() doing normalization in all cases now (it already did for implicit case, since current_time() clamps). Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 42e729b9ddbb ("utimes: Clamp the timestamps before update") Cc: stable@vger.kernel.org # v5.4 Cc: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-08-30timestamp_truncate: Replace users of timespec64_truncDeepa Dinamani1-9/+12
Update the inode timestamp updates to use timestamp_truncate() instead of timespec64_trunc(). The change was mostly generated by the following coccinelle script. virtual context virtual patch @r1 depends on patch forall@ struct inode *inode; identifier i_xtime =~ "^i_[acm]time$"; expression e; @@ inode->i_xtime = - timespec64_trunc( + timestamp_truncate( ..., - e); + inode); Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Jeff Layton <jlayton@kernel.org> Cc: adrian.hunter@intel.com Cc: dedekind1@gmail.com Cc: gregkh@linuxfoundation.org Cc: hch@lst.de Cc: jaegeuk@kernel.org Cc: jlbec@evilplan.org Cc: richard@nod.at Cc: tj@kernel.org Cc: yuchao0@huawei.com Cc: linux-f2fs-devel@lists.sourceforge.net Cc: linux-ntfs-dev@lists.sourceforge.net Cc: linux-mtd@lists.infradead.org
2018-07-03fs: Fix attr.c kernel-docMatthew Wilcox1-2/+3
A couple of minor warnings. Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-06-15Merge tag 'vfs-timespec64' of ↵Linus Torvalds1-7/+7
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground Pull inode timestamps conversion to timespec64 from Arnd Bergmann: "This is a late set of changes from Deepa Dinamani doing an automated treewide conversion of the inode and iattr structures from 'timespec' to 'timespec64', to push the conversion from the VFS layer into the individual file systems. As Deepa writes: 'The series aims to switch vfs timestamps to use struct timespec64. Currently vfs uses struct timespec, which is not y2038 safe. The series involves the following: 1. Add vfs helper functions for supporting struct timepec64 timestamps. 2. Cast prints of vfs timestamps to avoid warnings after the switch. 3. Simplify code using vfs timestamps so that the actual replacement becomes easy. 4. Convert vfs timestamps to use struct timespec64 using a script. This is a flag day patch. Next steps: 1. Convert APIs that can handle timespec64, instead of converting timestamps at the boundaries. 2. Update internal data structures to avoid timestamp conversions' Thomas Gleixner adds: 'I think there is no point to drag that out for the next merge window. The whole thing needs to be done in one go for the core changes which means that you're going to play that catchup game forever. Let's get over with it towards the end of the merge window'" * tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground: pstore: Remove bogus format string definition vfs: change inode times to use struct timespec64 pstore: Convert internal records to timespec64 udf: Simplify calls to udf_disk_stamp_to_time fs: nfs: get rid of memcpys for inode times ceph: make inode time prints to be long long lustre: Use long long type to print inode time fs: add timespec64_truncate()
2018-06-06vfs: change inode times to use struct timespec64Deepa Dinamani1-7/+7
struct timespec is not y2038 safe. Transition vfs to use y2038 safe struct timespec64 instead. The change was made with the help of the following cocinelle script. This catches about 80% of the changes. All the header file and logic changes are included in the first 5 rules. The rest are trivial substitutions. I avoid changing any of the function signatures or any other filesystem specific data structures to keep the patch simple for review. The script can be a little shorter by combining different cases. But, this version was sufficient for my usecase. virtual patch @ depends on patch @ identifier now; @@ - struct timespec + struct timespec64 current_time ( ... ) { - struct timespec now = current_kernel_time(); + struct timespec64 now = current_kernel_time64(); ... - return timespec_trunc( + return timespec64_trunc( ... ); } @ depends on patch @ identifier xtime; @@ struct \( iattr \| inode \| kstat \) { ... - struct timespec xtime; + struct timespec64 xtime; ... } @ depends on patch @ identifier t; @@ struct inode_operations { ... int (*update_time) (..., - struct timespec t, + struct timespec64 t, ...); ... } @ depends on patch @ identifier t; identifier fn_update_time =~ "update_time$"; @@ fn_update_time (..., - struct timespec *t, + struct timespec64 *t, ...) { ... } @ depends on patch @ identifier t; @@ lease_get_mtime( ... , - struct timespec *t + struct timespec64 *t ) { ... } @te depends on patch forall@ identifier ts; local idexpression struct inode *inode_node; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn_update_time =~ "update_time$"; identifier fn; expression e, E3; local idexpression struct inode *node1; local idexpression struct inode *node2; local idexpression struct iattr *attr1; local idexpression struct iattr *attr2; local idexpression struct iattr attr; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; @@ ( ( - struct timespec ts; + struct timespec64 ts; | - struct timespec ts = current_time(inode_node); + struct timespec64 ts = current_time(inode_node); ) <+... when != ts ( - timespec_equal(&inode_node->i_xtime, &ts) + timespec64_equal(&inode_node->i_xtime, &ts) | - timespec_equal(&ts, &inode_node->i_xtime) + timespec64_equal(&ts, &inode_node->i_xtime) | - timespec_compare(&inode_node->i_xtime, &ts) + timespec64_compare(&inode_node->i_xtime, &ts) | - timespec_compare(&ts, &inode_node->i_xtime) + timespec64_compare(&ts, &inode_node->i_xtime) | ts = current_time(e) | fn_update_time(..., &ts,...) | inode_node->i_xtime = ts | node1->i_xtime = ts | ts = inode_node->i_xtime | <+... attr1->ia_xtime ...+> = ts | ts = attr1->ia_xtime | ts.tv_sec | ts.tv_nsec | btrfs_set_stack_timespec_sec(..., ts.tv_sec) | btrfs_set_stack_timespec_nsec(..., ts.tv_nsec) | - ts = timespec64_to_timespec( + ts = ... -) | - ts = ktime_to_timespec( + ts = ktime_to_timespec64( ...) | - ts = E3 + ts = timespec_to_timespec64(E3) | - ktime_get_real_ts(&ts) + ktime_get_real_ts64(&ts) | fn(..., - ts + timespec64_to_timespec(ts) ,...) ) ...+> ( <... when != ts - return ts; + return timespec64_to_timespec(ts); ...> ) | - timespec_equal(&node1->i_xtime1, &node2->i_xtime2) + timespec64_equal(&node1->i_xtime2, &node2->i_xtime2) | - timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2) + timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2) | - timespec_compare(&node1->i_xtime1, &node2->i_xtime2) + timespec64_compare(&node1->i_xtime1, &node2->i_xtime2) | node1->i_xtime1 = - timespec_trunc(attr1->ia_xtime1, + timespec64_trunc(attr1->ia_xtime1, ...) | - attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2, + attr1->ia_xtime1 = timespec64_trunc(attr2->ia_xtime2, ...) | - ktime_get_real_ts(&attr1->ia_xtime1) + ktime_get_real_ts64(&attr1->ia_xtime1) | - ktime_get_real_ts(&attr.ia_xtime1) + ktime_get_real_ts64(&attr.ia_xtime1) ) @ depends on patch @ struct inode *node; struct iattr *attr; identifier fn; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; expression e; @@ ( - fn(node->i_xtime); + fn(timespec64_to_timespec(node->i_xtime)); | fn(..., - node->i_xtime); + timespec64_to_timespec(node->i_xtime)); | - e = fn(attr->ia_xtime); + e = fn(timespec64_to_timespec(attr->ia_xtime)); ) @ depends on patch forall @ struct inode *node; struct iattr *attr; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); fn (..., - &attr->ia_xtime, + &ts, ...); ) ...+> } @ depends on patch forall @ struct inode *node; struct iattr *attr; struct kstat *stat; identifier ia_xtime =~ "^ia_[acm]time$"; identifier i_xtime =~ "^i_[acm]time$"; identifier xtime =~ "^[acm]time$"; identifier fn, ret; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime); + &ts); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime); + &ts); | + ts = timespec64_to_timespec(stat->xtime); ret = fn (..., - &stat->xtime); + &ts); ) ...+> } @ depends on patch @ struct inode *node; struct inode *node2; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier i_xtime3 =~ "^i_[acm]time$"; struct iattr *attrp; struct iattr *attrp2; struct iattr attr ; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; struct kstat *stat; struct kstat stat1; struct timespec64 ts; identifier xtime =~ "^[acmb]time$"; expression e; @@ ( ( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1 ; | node->i_xtime2 = \( node2->i_xtime1 \| timespec64_trunc(...) \); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \); | stat->xtime = node2->i_xtime1; | stat1.xtime = node2->i_xtime1; | ( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1 ; | ( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2; | - e = node->i_xtime1; + e = timespec64_to_timespec( node->i_xtime1 ); | - e = attrp->ia_xtime1; + e = timespec64_to_timespec( attrp->ia_xtime1 ); | node->i_xtime1 = current_time(...); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | - node->i_xtime1 = e; + node->i_xtime1 = timespec_to_timespec64(e); ) Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Cc: <anton@tuxera.com> Cc: <balbi@kernel.org> Cc: <bfields@fieldses.org> Cc: <darrick.wong@oracle.com> Cc: <dhowells@redhat.com> Cc: <dsterba@suse.com> Cc: <dwmw2@infradead.org> Cc: <hch@lst.de> Cc: <hirofumi@mail.parknet.co.jp> Cc: <hubcap@omnibond.com> Cc: <jack@suse.com> Cc: <jaegeuk@kernel.org> Cc: <jaharkes@cs.cmu.edu> Cc: <jslaby@suse.com> Cc: <keescook@chromium.org> Cc: <mark@fasheh.com> Cc: <miklos@szeredi.hu> Cc: <nico@linaro.org> Cc: <reiserfs-devel@vger.kernel.org> Cc: <richard@nod.at> Cc: <sage@redhat.com> Cc: <sfrench@samba.org> Cc: <swhiteho@redhat.com> Cc: <tj@kernel.org> Cc: <trond.myklebust@primarydata.com> Cc: <tytso@mit.edu> Cc: <viro@zeniv.linux.org.uk>
2018-05-24fs: Allow superblock owner to replace invalid owners of inodesEric W. Biederman1-8/+28
Allow users with CAP_SYS_CHOWN over the superblock of a filesystem to chown files when inode owner is invalid. Ordinarily the capable_wrt_inode_uidgid check is sufficient to allow access to files but when the underlying filesystem has uids or gids that don't map to the current user namespace it is not enough, so the chown permission checks need to be extended to allow this case. Calling chown on filesystem nodes whose uid or gid don't map is necessary if those nodes are going to be modified as writing back inodes which contain uids or gids that don't map is likely to cause filesystem corruption of the uid or gid fields. Once chown has been called the existing capable_wrt_inode_uidgid checks are sufficient to allow the owner of a superblock to do anything the global root user can do with an appropriate set of capabilities. An ordinary filesystem mountable by a userns root will limit all uids and gids in s_user_ns or the INVALID_UID and INVALID_GID to flag all others. So having this added permission limited to just INVALID_UID and INVALID_GID is sufficient to handle every case on an ordinary filesystem. Of the virtual filesystems at least proc is known to set s_user_ns to something other than &init_user_ns, while at the same time presenting some files owned by GLOBAL_ROOT_UID. Those files the mounter of proc in a user namespace should not be able to chown to get access to. Limiting the relaxation in permission to just the minimum of allowing changing INVALID_UID and INVALID_GID prevents problems with cases like that. The original version of this patch was written by: Seth Forshee. I have rewritten and rethought this patch enough so it's really not the same thing (certainly it needs a different description), but he deserves credit for getting out there and getting the conversation started, and finding the potential gotcha's and putting up with my semi-paranoid feedback. Inspired-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-11Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: ">rename2() work from Miklos + current_time() from Deepa" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Replace current_fs_time() with current_time() fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps fs: Replace CURRENT_TIME with current_time() for inode timestamps fs: proc: Delete inode time initializations in proc_alloc_inode() vfs: Add current_time() api vfs: add note about i_op->rename changes to porting fs: rename "rename2" i_op to "rename" vfs: remove unused i_op->rename fs: make remaining filesystems use .rename2 libfs: support RENAME_NOREPLACE in simple_rename() fs: support RENAME_NOREPLACE for local filesystems ncpfs: fix unused variable warning
2016-10-08Merge remote-tracking branch 'jk/vfs' into work.miscAl Viro1-12/+23
2016-09-28fs: Replace current_fs_time() with current_time()Deepa Dinamani1-1/+1
current_fs_time() uses struct super_block* as an argument. As per Linus's suggestion, this is changed to take struct inode* as a parameter instead. This is because the function is primarily meant for vfs inode timestamps. Also the function was renamed as per Arnd's suggestion. Change all calls to current_fs_time() to use the new current_time() function instead. current_fs_time() will be deleted. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-09-22fs: Avoid premature clearing of capabilitiesJan Kara1-6/+14
Currently, notify_change() clears capabilities or IMA attributes by calling security_inode_killpriv() before calling into ->setattr. Thus it happens before any other permission checks in inode_change_ok() and user is thus allowed to trigger clearing of capabilities or IMA attributes for any file he can look up e.g. by calling chown for that file. This is unexpected and can lead to user DoSing a system. Fix the problem by calling security_inode_killpriv() at the end of inode_change_ok() instead of from notify_change(). At that moment we are sure user has permissions to do the requested change. References: CVE-2015-1350 Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2016-09-22fs: Give dentry to inode_change_ok() instead of inodeJan Kara1-6/+9
inode_change_ok() will be resposible for clearing capabilities and IMA extended attributes and as such will need dentry. Give it as an argument to inode_change_ok() instead of an inode. Also rename inode_change_ok() to setattr_prepare() to better relect that it does also some modifications in addition to checks. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2016-09-16vfs: move permission checking into notify_change() for utimes(NULL)Miklos Szeredi1-0/+15
This fixes a bug where the permission was not properly checked in overlayfs. The testcase is ltp/utimensat01. It is also cleaner and safer to do the permission checking in the vfs helper instead of the caller. This patch introduces an additional ia_valid flag ATTR_TOUCH (since touch(1) is the most obvious user of utimes(NULL)) that is passed into notify_change whenever the conditions for this special permission checking mode are met. Reported-by: Aihua Zhang <zhangaihua1@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Aihua Zhang <zhangaihua1@huawei.com> Cc: <stable@vger.kernel.org> # v3.18+
2016-07-05vfs: Don't modify inodes with a uid or gid unknown to the vfsEric W. Biederman1-0/+8
When a filesystem outside of init_user_ns is mounted it could have uids and gids stored in it that do not map to init_user_ns. The plan is to allow those filesystems to set i_uid to INVALID_UID and i_gid to INVALID_GID for unmapped uids and gids and then to handle that strange case in the vfs to ensure there is consistent robust handling of the weirdness. Upon a careful review of the vfs and filesystems about the only case where there is any possibility of confusion or trouble is when the inode is written back to disk. In that case filesystems typically read the inode->i_uid and inode->i_gid and write them to disk even when just an inode timestamp is being updated. Which leads to a rule that is very simple to implement and understand inodes whose i_uid or i_gid is not valid may not be written. In dealing with access times this means treat those inodes as if the inode flag S_NOATIME was set. Reads of the inodes appear safe and useful, but any write or modification is disallowed. The only inode write that is allowed is a chown that sets the uid and gid on the inode to valid values. After such a chown the inode is normal and may be treated as such. Denying all writes to inodes with uids or gids unknown to the vfs also prevents several oddball cases where corruption would have occurred because the vfs does not have complete information. One problem case that is prevented is attempting to use the gid of a directory for new inodes where the directories sgid bit is set but the directories gid is not mapped. Another problem case avoided is attempting to update the evm hash after setxattr, removexattr, and setattr. As the evm hash includeds the inode->i_uid or inode->i_gid not knowning the uid or gid prevents a correct evm hash from being computed. evm hash verification also fails when i_uid or i_gid is unknown but that is essentially harmless as it does not cause filesystem corruption. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-06-28fs: Refuse uid/gid changes which don't map into s_user_nsSeth Forshee1-0/+11
Add checks to notify_change to verify that uid and gid changes will map into the superblock's user namespace. If they do not fail with -EOVERFLOW. This is mandatory so that fileystems don't have to even think of dealing with ia_uid and ia_gid that --EWB Moved the test from inode_change_ok to notify_change Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2016-01-23wrappers for ->i_mutex accessAl Viro1-1/+1
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-06-11fs,userns: Change inode_capable to capable_wrt_inode_uidgidAndy Lutomirski1-4/+4
The kernel has no concept of capabilities with respect to inodes; inodes exist independently of namespaces. For example, inode_capable(inode, CAP_LINUX_IMMUTABLE) would be nonsense. This patch changes inode_capable to check for uid and gid mappings and renames it to capable_wrt_inode_uidgid, which should make it more obvious what it does. Fixes CVE-2014-4014. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Chinner <david@fromorbit.com> Cc: stable@vger.kernel.org Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-06fs: fix iversion handlingChristoph Hellwig1-5/+0
Currently notify_change directly updates i_version for size updates, which not only is counter to how all other fields are updated through struct iattr, but also breaks XFS, which need inode updates to happen under its own lock, and synchronized to the structure that gets written to the log. Remove the update in the common code, and it to btrfs and ext4, XFS already does a proper updaste internally and currently gets a double update with the existing code. IMHO this is 3.13 and -stable material and should go in through the XFS tree. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Acked-by: Jan Kara <jack@suse.cz> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-11-09locks: break delegations on any attribute modificationJ. Bruce Fields1-1/+24
NFSv4 uses leases to guarantee that clients can cache metadata as well as data. Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: David Howells <dhowells@redhat.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Dustin Kirkland <dustin.kirkland@gazzang.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>