diff options
| author | Jan Kara <jack@suse.cz> | 2016-09-19 18:39:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-08 08:44:10 +0300 |
| commit | d8333c045f045385a914013a220cd1ed54c88d48 (patch) | |
| tree | 6f3354eeb66b4277f03d695b1c88d1d2f091f6c6 /fs/9p | |
| parent | 5a7b3b1ec16b6bfa57752d37292988e64fcdd172 (diff) | |
| download | linux-d8333c045f045385a914013a220cd1ed54c88d48.tar.xz | |
posix_acl: Clear SGID bit when setting file permissions
commit 073931017b49d9458aa351605b43a7e34598caef upstream.
When file permissions are modified via chmod(2) and the user is not in
the owning group or capable of CAP_FSETID, the setgid bit is cleared in
inode_change_ok(). Setting a POSIX ACL via setxattr(2) sets the file
permissions as well as the new ACL, but doesn't clear the setgid bit in
a similar way; this allows to bypass the check in chmod(2). Fix that.
References: CVE-2016-7097
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/9p')
| -rw-r--r-- | fs/9p/acl.c | 40 |
1 files changed, 17 insertions, 23 deletions
diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 8482f2d11606..d3f5d487ae46 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -320,32 +320,26 @@ static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name, case ACL_TYPE_ACCESS: name = POSIX_ACL_XATTR_ACCESS; if (acl) { - umode_t mode = inode->i_mode; - retval = posix_acl_equiv_mode(acl, &mode); - if (retval < 0) + struct iattr iattr; + + retval = posix_acl_update_mode(inode, &iattr.ia_mode, &acl); + if (retval) goto err_out; - else { - struct iattr iattr; - if (retval == 0) { - /* - * ACL can be represented - * by the mode bits. So don't - * update ACL. - */ - acl = NULL; - value = NULL; - size = 0; - } - /* Updte the mode bits */ - iattr.ia_mode = ((mode & S_IALLUGO) | - (inode->i_mode & ~S_IALLUGO)); - iattr.ia_valid = ATTR_MODE; - /* FIXME should we update ctime ? - * What is the following setxattr update the - * mode ? + if (!acl) { + /* + * ACL can be represented + * by the mode bits. So don't + * update ACL. */ - v9fs_vfs_setattr_dotl(dentry, &iattr); + value = NULL; + size = 0; } + iattr.ia_valid = ATTR_MODE; + /* FIXME should we update ctime ? + * What is the following setxattr update the + * mode ? + */ + v9fs_vfs_setattr_dotl(dentry, &iattr); } break; case ACL_TYPE_DEFAULT: |