9p locks: fix glock.client_id leak in do_lock (b4dc44b3) · Commits · 戴 / test

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 ("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>

fs/9p/vfs_file.c

+14 −2

Original line number	Diff line number	Diff line
		@@ -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:
		@@ -294,6 +304,8 @@ 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;
		}
		out:
		if (glock.client_id != fid->clnt->name)
		kfree(glock.client_id);
		return res;
		}

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