| Message ID | 20170222000629.7995-1-tuomas@tuxera.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 22 Feb 2017 02:06:29 +0200 Tuomas Tynkkynen <tuomas@tuxera.com> wrote: > Commit fd2421f54423 ("fs/9p: When doing inode lookup compare qid details > and inode mode bits.") transformed v9fs_qid_iget() to use iget5_locked() > instead of iget_locked(). However, the test() callback is not checking > fid.path at all, which means that a lookup in the inode cache can now > accidentally locate a completely wrong inode from the same inode hash > bucket if the other fields (qid.type and qid.version) match. > Al, does this sound sensible? (or if there is someone else picking up 9p patches, let me know). Thanks! - Tuomas
Reviewed-by: Latchesar Ionkov <lucho@ionkov.net> On Tue, Feb 21, 2017 at 6:06 PM, Tuomas Tynkkynen <tuomas@tuxera.com> wrote: > Commit fd2421f54423 ("fs/9p: When doing inode lookup compare qid details > and inode mode bits.") transformed v9fs_qid_iget() to use iget5_locked() > instead of iget_locked(). However, the test() callback is not checking > fid.path at all, which means that a lookup in the inode cache can now > accidentally locate a completely wrong inode from the same inode hash > bucket if the other fields (qid.type and qid.version) match. > > Fixes: fd2421f54423 ("fs/9p: When doing inode lookup compare qid details and inode mode bits.") > Cc: stable@vger.kernel.org > Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com> > --- > Does this sound sensible? I have never reproduced the problem myself but > reportedly this patch solves some really weird problems where the > symptoms match (wrong files being opened unpredictably). > --- > fs/9p/vfs_inode.c | 3 +++ > fs/9p/vfs_inode_dotl.c | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c > index 30ca770c5e0b..f8ab4a66acaf 100644 > --- a/fs/9p/vfs_inode.c > +++ b/fs/9p/vfs_inode.c > @@ -483,6 +483,9 @@ static int v9fs_test_inode(struct inode *inode, void *data) > > if (v9inode->qid.type != st->qid.type) > return 0; > + > + if (v9inode->qid.path != st->qid.path) > + return 0; > return 1; > } > > diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c > index afaa4b6de801..c3dd0d42bb3a 100644 > --- a/fs/9p/vfs_inode_dotl.c > +++ b/fs/9p/vfs_inode_dotl.c > @@ -87,6 +87,9 @@ static int v9fs_test_inode_dotl(struct inode *inode, void *data) > > if (v9inode->qid.type != st->qid.type) > return 0; > + > + if (v9inode->qid.path != st->qid.path) > + return 0; > return 1; > } > > -- > 2.11.1 >
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index 30ca770c5e0b..f8ab4a66acaf 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -483,6 +483,9 @@ static int v9fs_test_inode(struct inode *inode, void *data) if (v9inode->qid.type != st->qid.type) return 0; + + if (v9inode->qid.path != st->qid.path) + return 0; return 1; } diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index afaa4b6de801..c3dd0d42bb3a 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -87,6 +87,9 @@ static int v9fs_test_inode_dotl(struct inode *inode, void *data) if (v9inode->qid.type != st->qid.type) return 0; + + if (v9inode->qid.path != st->qid.path) + return 0; return 1; }
Commit fd2421f54423 ("fs/9p: When doing inode lookup compare qid details and inode mode bits.") transformed v9fs_qid_iget() to use iget5_locked() instead of iget_locked(). However, the test() callback is not checking fid.path at all, which means that a lookup in the inode cache can now accidentally locate a completely wrong inode from the same inode hash bucket if the other fields (qid.type and qid.version) match. Fixes: fd2421f54423 ("fs/9p: When doing inode lookup compare qid details and inode mode bits.") Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com> --- Does this sound sensible? I have never reproduced the problem myself but reportedly this patch solves some really weird problems where the symptoms match (wrong files being opened unpredictably). --- fs/9p/vfs_inode.c | 3 +++ fs/9p/vfs_inode_dotl.c | 3 +++ 2 files changed, 6 insertions(+)