From 3d019a541cac0b8cc1ba6891f8c9f99bfe37d79e Mon Sep 17 00:00:00 2001 From: Steven Luong Date: Sun, 28 Feb 2021 09:45:16 -0800 Subject: [PATCH] memif: Validate descriptors within process boudary We hit a crash when the client sends us a bogus deescriptor which causes us to access memory beyong the mapping. While the client clearly should not do that, it is rather cheap for VPP to validate the descriptor instead of crash and burn. Type: fix Signed-off-by: Steven Luong Change-Id: Id09035810939f5f98530f212f0b23e606132251d --- src/plugins/memif/node.c | 47 +++++++++++++++++++++++++++-------------------- 1 file changed, 27 insertions(+), 20 deletions(-) diff --git a/src/plugins/memif/node.c b/src/plugins/memif/node.c index 270fd59ca47..675acf3b49e 100644 --- a/src/plugins/memif/node.c +++ b/src/plugins/memif/node.c @@ -30,9 +30,10 @@ #include #include -#define foreach_memif_input_error \ - _(BUFFER_ALLOC_FAIL, "buffer allocation failed") \ - _(NOT_IP, "not ip packet") +#define foreach_memif_input_error \ + _ (BUFFER_ALLOC_FAIL, "buffer allocation failed") \ + _ (BAD_DESC, "bad descriptor") \ + _ (NOT_IP, "not ip packet") typedef enum { @@ -199,6 +200,7 @@ memif_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node, memif_packet_op_t *po; memif_region_index_t last_region = ~0; void *last_region_shm = 0; + void *last_region_max = 0; mq = vec_elt_at_index (mif->rx_queues, qid); ring = mq->ring; @@ -249,26 +251,31 @@ memif_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node, { last_region_shm = mif->regions[d0->region].shm; last_region = d0->region; + last_region_max = + last_region_shm + mif->regions[last_region].region_size; } mb0 = last_region_shm + d0->offset; - do - { - u32 dst_free = buffer_size - dst_off; - if (dst_free == 0) - { - dst_off = 0; - dst_free = buffer_size; - n_buffers++; - } - u32 bytes_to_copy = clib_min (dst_free, n_bytes_left); - memif_add_copy_op (ptd, mb0 + src_off, bytes_to_copy, dst_off, - n_buffers - 1); - n_bytes_left -= bytes_to_copy; - src_off += bytes_to_copy; - dst_off += bytes_to_copy; - } - while (PREDICT_FALSE (n_bytes_left)); + if (PREDICT_FALSE (mb0 + n_bytes_left > last_region_max)) + vlib_error_count (vm, node->node_index, MEMIF_INPUT_ERROR_BAD_DESC, 1); + else + do + { + u32 dst_free = buffer_size - dst_off; + if (dst_free == 0) + { + dst_off = 0; + dst_free = buffer_size; + n_buffers++; + } + u32 bytes_to_copy = clib_min (dst_free, n_bytes_left); + memif_add_copy_op (ptd, mb0 + src_off, bytes_to_copy, dst_off, + n_buffers - 1); + n_bytes_left -= bytes_to_copy; + src_off += bytes_to_copy; + dst_off += bytes_to_copy; + } + while (PREDICT_FALSE (n_bytes_left)); cur_slot++; n_slots--; -- 2.16.6