From 51e23ea7fd49cb04ba33db3bfbeba690a2f7c5b4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Dr=2E=20Lars=20V=C3=B6lker?= Date: Fri, 3 Feb 2023 19:42:03 +0100 Subject: [PATCH] ISO15765/ISO10681 memory corruption bugfix Fixes a situation in which the code wrote behind the frag_id_high array and corrupted memory. Closes #18839 --- epan/dissectors/packet-iso10681.c | 7 ++++++- epan/dissectors/packet-iso15765.c | 8 ++++++-- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/epan/dissectors/packet-iso10681.c b/epan/dissectors/packet-iso10681.c index 9e749eea8cf..6772e936e06 100644 --- a/epan/dissectors/packet-iso10681.c +++ b/epan/dissectors/packet-iso10681.c @@ -340,7 +340,12 @@ dissect_iso10681(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 fr } if (!(pinfo->fd->visited)) { - frag_id += ((iso10681_frame->frag_id_high[frag_id]++) * 16); + DISSECTOR_ASSERT(frag_id < 16); + guint16 tmp = iso10681_frame->frag_id_high[frag_id]++; + /* Make sure that we assert on using more than 4096 (16*255) segments.*/ + DISSECTOR_ASSERT(iso10681_frame->frag_id_high[frag_id] != 0); + frag_id += tmp * 16; + /* Save the frag_id for subsequent dissection */ iso10681_info->frag_id = frag_id; } diff --git a/epan/dissectors/packet-iso15765.c b/epan/dissectors/packet-iso15765.c index 3157397bf21..4c73927c807 100644 --- a/epan/dissectors/packet-iso15765.c +++ b/epan/dissectors/packet-iso15765.c @@ -573,14 +573,18 @@ dissect_iso15765(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 bu tvbuff_t *new_tvb = NULL; iso15765_frame_t *iso15765_frame; guint16 frag_id = frag_id_low; - /* Get frame information */ iso15765_frame = (iso15765_frame_t *)wmem_map_lookup(iso15765_frame_table, GUINT_TO_POINTER(iso15765_info->seq)); if (iso15765_frame != NULL) { if (!(pinfo->fd->visited)) { - frag_id += ((iso15765_frame->frag_id_high[frag_id]++) * 16); + DISSECTOR_ASSERT(frag_id < 16); + guint16 tmp = iso15765_frame->frag_id_high[frag_id]++; + /* Make sure that we assert on using more than 4096 (16*255) segments.*/ + DISSECTOR_ASSERT(iso15765_frame->frag_id_high[frag_id] != 0); + frag_id += tmp * 16; + /* Save the frag_id for subsequent dissection */ iso15765_info->frag_id = frag_id; -- GitLab