[patch 02/11] ipc: don't allocate a copy larger than max

[akpm@xxxxxxxxxxxxxxxxxxxx]

From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Subject: ipc: don't allocate a copy larger than max

When MSG_COPY is set, a duplicate message must be allocated for the copy
before locking the queue.  However, the copy could not be larger than was
sent which is limited to msg_ctlmax.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Acked-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 ipc/msg.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff -puN ipc/msg.c~ipc-dont-allocate-a-copy-larger-than-max ipc/msg.c
--- a/ipc/msg.c~ipc-dont-allocate-a-copy-larger-than-max
+++ a/ipc/msg.c
@@ -820,15 +820,17 @@ long do_msgrcv(int msqid, void __user *b
 	struct msg_msg *copy = NULL;
 	unsigned long copy_number = 0;
 
+	ns = current->nsproxy->ipc_ns;
+
 	if (msqid < 0 || (long) bufsz < 0)
 		return -EINVAL;
 	if (msgflg & MSG_COPY) {
-		copy = prepare_copy(buf, bufsz, msgflg, &msgtyp, &copy_number);
+		copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax),
+				    msgflg, &msgtyp, &copy_number);
 		if (IS_ERR(copy))
 			return PTR_ERR(copy);
 	}
 	mode = convert_mode(&msgtyp, msgflg);
-	ns = current->nsproxy->ipc_ns;
 
 	msq = msg_lock_check(ns, msqid);
 	if (IS_ERR(msq)) {
_
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html