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authorBen Hutchings <ben@decadent.org.uk>2016-06-22 21:43:35 +0300
committerJ. Bruce Fields <bfields@redhat.com>2016-06-24 19:11:52 +0300
commit999653786df6954a31044528ac3f7a5dadca08f4 (patch)
tree1591ca7fc7acbd0128b33701516f85276ad8ff06 /fs/nfsd/nfs2acl.c
parent485e71e8fb6356c08c7fc6bcce4bf02c9a9a663f (diff)
downloadlinux-999653786df6954a31044528ac3f7a5dadca08f4.tar.xz
nfsd: check permissions when setting ACLs
Use set_posix_acl, which includes proper permission checks, instead of calling ->set_acl directly. Without this anyone may be able to grant themselves permissions to a file by setting the ACL. Lock the inode to make the new checks atomic with respect to set_acl. (Also, nfsd was the only caller of set_acl not locking the inode, so I suspect this may fix other races.) This also simplifies the code, and ensures our ACLs are checked by posix_acl_valid. The permission checks and the inode locking were lost with commit 4ac7249e, which changed nfsd to use the set_acl inode operation directly instead of going through xattr handlers. Reported-by: David Sinquin <david@sinquin.eu> [agreunba@redhat.com: use set_posix_acl] Fixes: 4ac7249e Cc: Christoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd/nfs2acl.c')
-rw-r--r--fs/nfsd/nfs2acl.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/nfsd/nfs2acl.c b/fs/nfsd/nfs2acl.c
index 1580ea6fd64d..d08cd88155c7 100644
--- a/fs/nfsd/nfs2acl.c
+++ b/fs/nfsd/nfs2acl.c
@@ -104,22 +104,21 @@ static __be32 nfsacld_proc_setacl(struct svc_rqst * rqstp,
goto out;
inode = d_inode(fh->fh_dentry);
- if (!IS_POSIXACL(inode) || !inode->i_op->set_acl) {
- error = -EOPNOTSUPP;
- goto out_errno;
- }
error = fh_want_write(fh);
if (error)
goto out_errno;
- error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);
+ fh_lock(fh);
+
+ error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);
if (error)
- goto out_drop_write;
- error = inode->i_op->set_acl(inode, argp->acl_default,
- ACL_TYPE_DEFAULT);
+ goto out_drop_lock;
+ error = set_posix_acl(inode, ACL_TYPE_DEFAULT, argp->acl_default);
if (error)
- goto out_drop_write;
+ goto out_drop_lock;
+
+ fh_unlock(fh);
fh_drop_write(fh);
@@ -131,7 +130,8 @@ out:
posix_acl_release(argp->acl_access);
posix_acl_release(argp->acl_default);
return nfserr;
-out_drop_write:
+out_drop_lock:
+ fh_unlock(fh);
fh_drop_write(fh);
out_errno:
nfserr = nfserrno(error);