On Fri, 31 Jan 2014 16:13:19 -0500
Oleg Drokin <green@xxxxxxxxxxxxxx> wrote:
>
> On Jan 31, 2014, at 4:03 PM, Al Viro wrote:
> >> diff --git a/fs/namei.c b/fs/namei.c
> >> index bcb838e..e620937 100644
> >> --- a/fs/namei.c
> >> +++ b/fs/namei.c
> >> @@ -3931,6 +3931,7 @@ out_dput:
> >> goto retry;
> >> }
> >> if (retry_estale(error, how)) {
> >> + path_put(&old_path);
> >> how |= LOOKUP_REVAL;
> >> goto retry;
> >> }
> > Umm... That obviously can't be right - we have another goto retry
> > in the same situation (see in your diff context). I agree that
> > we have a leak there, but you've fixed only a half of it.
>
> Hm, you are right, I did not notice this other one somehow.
>
> So, not to take any guesses, should I convert the other goto retry into
> retry_deleg similar in style to what happens in rename and unlink, only
> make retry)deleg label before call to the security_path_link?
> After the call to the security_path_link?
> Or would you prefer to just free old_path in both cases?
>
> Bye,
> Oleg
Maybe something like this (untested) instead?
--------------------------8<---------------------------
[PATCH] vfs: fix linkat old_path reference leak
Cc: <stable@xxxxxxxxxxxxxxx> # v3.8+
Reported-by: Oleg Drokin <green@xxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/namei.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 46dbd31..e70dd81 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3927,8 +3927,10 @@ retry:
new_dentry = user_path_create(newdfd, newname, &new_path,
(how & LOOKUP_REVAL));
error = PTR_ERR(new_dentry);
- if (IS_ERR(new_dentry))
+ if (IS_ERR(new_dentry)) {
+ path_put(&old_path);
goto out;
+ }
error = -EXDEV;
if (old_path.mnt != new_path.mnt)
@@ -3942,6 +3944,7 @@ retry:
error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode);
out_dput:
done_path_create(&new_path, new_dentry);
+ path_put(&old_path);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
@@ -3952,8 +3955,6 @@ out_dput:
goto retry;
}
out:
- path_put(&old_path);
-
return error;
}
--
1.8.5.3
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