Commit 88b9e456 authored by Peter Hurley's avatar Peter Hurley Committed by Linus Torvalds

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: default avatarPeter Hurley <peter@hurleysoftware.com>
Acked-by: default avatarStanislav Kinsbursky <skinsbursky@parallels.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e1082f45
...@@ -820,15 +820,17 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, ...@@ -820,15 +820,17 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
struct msg_msg *copy = NULL; struct msg_msg *copy = NULL;
unsigned long copy_number = 0; unsigned long copy_number = 0;
ns = current->nsproxy->ipc_ns;
if (msqid < 0 || (long) bufsz < 0) if (msqid < 0 || (long) bufsz < 0)
return -EINVAL; return -EINVAL;
if (msgflg & MSG_COPY) { 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)) if (IS_ERR(copy))
return PTR_ERR(copy); return PTR_ERR(copy);
} }
mode = convert_mode(&msgtyp, msgflg); mode = convert_mode(&msgtyp, msgflg);
ns = current->nsproxy->ipc_ns;
msq = msg_lock_check(ns, msqid); msq = msg_lock_check(ns, msqid);
if (IS_ERR(msq)) { if (IS_ERR(msq)) {
......
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