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authorDominique Martinet <dominique.martinet@cea.fr>2018-09-07 19:18:43 +0300
committerDominique Martinet <dominique.martinet@cea.fr>2018-09-07 19:52:35 +0300
commitb4dc44b3cac9e8327e0655f530ed0c46f2e6214c (patch)
tree0c6ced4f69d74af170161fdd37e67c97eaebdeab /fs/9p
parentef5305f1f72eb1cfcda25c382bb0368509c0385b (diff)
downloadlinux-b4dc44b3cac9e8327e0655f530ed0c46f2e6214c.tar.xz
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.c16
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;
}