From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40475) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbQfb-0007wZ-8S for qemu-devel@nongnu.org; Mon, 14 Sep 2015 06:07:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZbQfX-0008MR-62 for qemu-devel@nongnu.org; Mon, 14 Sep 2015 06:07:31 -0400 From: Paolo Bonzini Date: Mon, 14 Sep 2015 12:07:22 +0200 Message-Id: <1442225242-27908-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH] pc: check for underflow in load_linux List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org If (setup_size+1)*512 is small enough, kernel_size -= setup_size can allocate a huge amount of memory. Avoid that. Signed-off-by: Paolo Bonzini --- hw/i386/pc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 56aecce..6a312bd 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -986,6 +986,10 @@ static void load_linux(PCMachineState *pcms, setup_size = 4; } setup_size = (setup_size+1)*512; + if (setup_size > kernel_size) { + fprintf(stderr, "qemu: invalid kernel header\n"); + exit(1); + } kernel_size -= setup_size; setup = g_malloc(setup_size); -- 2.5.0