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@hurleysoftware.com> Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 4 additions and 2 deletions
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@ -820,15 +820,17 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
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struct msg_msg *copy = NULL;
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unsigned long copy_number = 0;
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ns = current->nsproxy->ipc_ns;
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if (msqid < 0 || (long) bufsz < 0)
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return -EINVAL;
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if (msgflg & MSG_COPY) {
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copy = prepare_copy(buf, bufsz, msgflg, &msgtyp, ©_number);
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copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax),
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msgflg, &msgtyp, ©_number);
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if (IS_ERR(copy))
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return PTR_ERR(copy);
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}
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mode = convert_mode(&msgtyp, msgflg);
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ns = current->nsproxy->ipc_ns;
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msq = msg_lock_check(ns, msqid);
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if (IS_ERR(msq)) {
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