From 8f1d22d97046052424c7daf7c657bb68a816c540 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 9 Nov 2018 21:30:28 +0400 Subject: [PATCH] vhost-user-bridge: fix recvmsg iovlen MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After iov_discard_front(), the iov may be smaller than its initial size. Fixes the heap-buffer-overflow spotted by ASAN: ==9036==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6060000001e0 at pc 0x7fe632eca3f0 bp 0x7ffddc4a05a0 sp 0x7ffddc49fd48 WRITE of size 32 at 0x6060000001e0 thread T0 #0 0x7fe632eca3ef (/lib64/libasan.so.5+0x773ef) #1 0x7fe632ecad23 in __interceptor_recvmsg (/lib64/libasan.so.5+0x77d23) #2 0x561e7491936b in vubr_backend_recv_cb /home/elmarco/src/qemu/tests/vhost-user-bridge.c:333 #3 0x561e74917711 in dispatcher_wait /home/elmarco/src/qemu/tests/vhost-user-bridge.c:160 #4 0x561e7491c3b5 in vubr_run /home/elmarco/src/qemu/tests/vhost-user-bridge.c:725 #5 0x561e7491c85c in main /home/elmarco/src/qemu/tests/vhost-user-bridge.c:806 #6 0x7fe631a6c412 in __libc_start_main (/lib64/libc.so.6+0x24412) #7 0x561e7491667d in _start (/home/elmarco/src/qemu/build/tests/vhost-user-bridge+0x3967d) 0x6060000001e0 is located 0 bytes to the right of 64-byte region [0x6060000001a0,0x6060000001e0) allocated by thread T0 here: #0 0x7fe632f42848 in __interceptor_malloc (/lib64/libasan.so.5+0xef848) #1 0x561e7493acd8 in virtqueue_alloc_element /home/elmarco/src/qemu/contrib/libvhost-user/libvhost-user.c:1848 #2 0x561e7493c2a8 in vu_queue_pop /home/elmarco/src/qemu/contrib/libvhost-user/libvhost-user.c:1954 #3 0x561e749189bf in vubr_backend_recv_cb /home/elmarco/src/qemu/tests/vhost-user-bridge.c:297 #4 0x561e74917711 in dispatcher_wait /home/elmarco/src/qemu/tests/vhost-user-bridge.c:160 #5 0x561e7491c3b5 in vubr_run /home/elmarco/src/qemu/tests/vhost-user-bridge.c:725 #6 0x561e7491c85c in main /home/elmarco/src/qemu/tests/vhost-user-bridge.c:806 #7 0x7fe631a6c412 in __libc_start_main (/lib64/libc.so.6+0x24412) SUMMARY: AddressSanitizer: heap-buffer-overflow (/lib64/libasan.so.5+0x773ef) Shadow bytes around the buggy address: 0x0c0c7fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c0c7fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c0c7fff8000: fa fa fa fa 00 00 00 00 00 00 05 fa fa fa fa fa 0x0c0c7fff8010: 00 00 00 00 00 00 00 00 fa fa fa fa fd fd fd fd 0x0c0c7fff8020: fd fd fd fd fa fa fa fa fd fd fd fd fd fd fd fd =>0x0c0c7fff8030: fa fa fa fa 00 00 00 00 00 00 00 00[fa]fa fa fa 0x0c0c7fff8040: fd fd fd fd fd fd fd fd fa fa fa fa fd fd fd fd 0x0c0c7fff8050: fd fd fd fd fa fa fa fa fd fd fd fd fd fd fd fd 0x0c0c7fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0c7fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c0c7fff8080: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Signed-off-by: Marc-André Lureau Message-Id: <20181109173028.3372-1-marcandre.lureau@redhat.com> Signed-off-by: Paolo BOnzini --- tests/vhost-user-bridge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tests/vhost-user-bridge.c b/tests/vhost-user-bridge.c index 0884294141..0cf8d0baca 100644 --- a/tests/vhost-user-bridge.c +++ b/tests/vhost-user-bridge.c @@ -323,7 +323,7 @@ vubr_backend_recv_cb(int sock, void *ctx) .msg_name = (struct sockaddr *) &vubr->backend_udp_dest, .msg_namelen = sizeof(struct sockaddr_in), .msg_iov = sg, - .msg_iovlen = elem->in_num, + .msg_iovlen = num, .msg_flags = MSG_DONTWAIT, }; do { -- GitLab