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| author | Dominique Martinet <dominique.martinet@cea.fr> | 2018-09-08 01:18:43 +0900 |
|---|---|---|
| committer | Dominique Martinet <dominique.martinet@cea.fr> | 2018-09-08 01:52:35 +0900 |
| commit | b4dc44b3cac9e8327e0655f530ed0c46f2e6214c (patch) | |
| tree | 0c6ced4f69d74af170161fdd37e67c97eaebdeab /fs/9p | |
| parent | ef5305f1f72eb1cfcda25c382bb0368509c0385b (diff) | |
| download | lwn-b4dc44b3cac9e8327e0655f530ed0c46f2e6214c.tar.gz lwn-b4dc44b3cac9e8327e0655f530ed0c46f2e6214c.zip | |
9p locks: fix glock.client_id leak in do_lock
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.
Link: http://lkml.kernel.org/r/1536339057-21974-5-git-send-email-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Diffstat (limited to 'fs/9p')
| -rw-r--r-- | fs/9p/vfs_file.c | 16 |
1 files 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 @@ out_unlock: 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; } |