From: Dominique Martinet <dominique.martinet@xxxxxx>
the 9p client code overwrites our glock.client_id pointing to a static
buffer by an allocated string holding the network provided value which
we do not care about; free and reset the value as appropriate.
This is almost identical to the leak in v9fs_file_getlock() fixed by
Al Viro in commit ce85dd58ad5a6 ("9p: we are leaking glock.client_id
in v9fs_file_getlock()"), which was returned as an error by a coverity
false positive -- while we are here attempt to make the code slightly
more robust to future change of the net/9p/client code and hopefully
more clear to coverity that there is no problem.
Signed-off-by: Dominique Martinet <dominique.martinet@xxxxxx>
---
fs/9p/vfs_file.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 73857ebaedfb..a25efa782fcc 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -208,6 +208,14 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
!= 0)
break;
+ /*
+ * p9_client_lock_dotl overwrites flock.client_id with the
+ * server message, free and reuse the client name
+ */
+ if (flock.client_id != fid->clnt->name) {
+ kfree(flock.client_id);
+ flock.client_id = fid->clnt->name;
+ }
}
/* map 9p status to VFS status */
@@ -239,6 +247,8 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
locks_lock_file_wait(filp, fl);
fl->fl_type = fl_type;
}
+ if (flock.client_id != fid->clnt->name)
+ kfree(flock.client_id);
out:
return res;
}
@@ -273,7 +283,7 @@ static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
res = p9_client_getlock_dotl(fid, &glock);
if (res < 0)
- return res;
+ goto out;
/* map 9p lock type to os lock type */
switch (glock.type) {
case P9_LOCK_TYPE_RDLCK:
@@ -294,7 +304,9 @@ static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
fl->fl_end = glock.start + glock.length - 1;
fl->fl_pid = -glock.proc_id;
}
- kfree(glock.client_id);
+out:
+ if (glock.client_id != fid->clnt->name)
+ kfree(glock.client_id);
return res;
}
--
2.17.1
