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| author | Dominique Martinet <dominique.martinet@cea.fr> | 2018-09-08 01:18:43 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-21 09:24:04 +0100 |
| commit | 491fc097e3d49f777d2e45ec3ae6341cff986f44 (patch) | |
| tree | c67ea3df4bd8f2f9db5451f0df0569da390310a8 /fs/9p | |
| parent | 442b54290c782f22a848941064625cad3e263f39 (diff) | |
| download | linux-rt-491fc097e3d49f777d2e45ec3ae6341cff986f44.tar.gz | |
9p locks: fix glock.client_id leak in do_lock
[ Upstream commit b4dc44b3cac9e8327e0655f530ed0c46f2e6214c ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 03c9e325bfbc..3a2f37ad1f89 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -204,6 +204,14 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl) break; if (schedule_timeout_interruptible(P9_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 */ @@ -235,6 +243,8 @@ 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; } @@ -269,7 +279,7 @@ 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: @@ -290,7 +300,9 @@ 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; } |