64 lines
2.7 KiB
Diff
64 lines
2.7 KiB
Diff
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From 3ff940652962c099b73ae3233322b8697b0d10ab Mon Sep 17 00:00:00 2001
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From: Gerald Combs <gerald@wireshark.org>
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Date: Fri, 2 Oct 2020 12:42:03 -0700
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Subject: [PATCH] FBZERO: Make sure our offset advances.
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Make sure our offset advances so that we don't infinitely loop.
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Fixes #16887.
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---
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epan/dissectors/packet-fbzero.c | 14 ++++++++++++--
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1 file changed, 12 insertions(+), 2 deletions(-)
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diff --git a/epan/dissectors/packet-fbzero.c b/epan/dissectors/packet-fbzero.c
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index 16ffb63cf1..132079cfaa 100644
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--- a/epan/dissectors/packet-fbzero.c
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+++ b/epan/dissectors/packet-fbzero.c
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@@ -66,6 +66,7 @@ static gint ett_fb_zero_tag_value = -1;
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static expert_field ei_fb_zero_tag_undecoded = EI_INIT;
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static expert_field ei_fb_zero_tag_length = EI_INIT;
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static expert_field ei_fb_zero_tag_unknown = EI_INIT;
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+static expert_field ei_fb_zero_length_invalid = EI_INIT;
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#define FBZERO_MIN_LENGTH 3
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@@ -261,18 +262,26 @@ dissect_fb_zero_tag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *fb_zero_tree,
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"Dissector for FB Zero Tag"
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" %s (%s) code not implemented, Contact"
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" Wireshark developers if you want this supported", tvb_get_string_enc(wmem_packet_scope(), tvb, offset-8, 4, ENC_ASCII|ENC_NA), val_to_str(tag, tag_vals, "Unknown"));
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- tag_offset += tag_len;
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+ goto end;
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break;
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}
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if(tag_offset != offset_end){
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/* Wrong Tag len... */
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proto_tree_add_expert(tag_tree, pinfo, &ei_fb_zero_tag_unknown, tvb, tag_offset_start + tag_offset, offset_end - tag_offset);
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- tag_offset = offset_end;
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+ // XXX Return instead?
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+ goto end;
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}
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tag_number--;
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}
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+
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+ end:
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+ if (offset + total_tag_len <= offset) {
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+ expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
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+ "Invalid total tag length: %u", total_tag_len);
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+ return offset + tvb_reported_length_remaining(tvb, offset);
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+ }
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return offset + total_tag_len;
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}
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@@ -562,6 +571,7 @@ proto_register_fb_zero(void)
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{ &ei_fb_zero_tag_undecoded, { "fb_zero.tag.undecoded", PI_UNDECODED, PI_NOTE, "Dissector for FB Zero Tag code not implemented, Contact Wireshark developers if you want this supported", EXPFILL }},
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{ &ei_fb_zero_tag_length, { "fb_zero.tag.length.truncated", PI_MALFORMED, PI_NOTE, "Truncated Tag Length...", EXPFILL }},
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{ &ei_fb_zero_tag_unknown, { "fb_zero.tag.unknown.data", PI_UNDECODED, PI_NOTE, "Unknown Data", EXPFILL }},
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+ { &ei_fb_zero_length_invalid, { "fb_zero.length.invalid", PI_PROTOCOL, PI_WARN, "Invalid length", EXPFILL }},
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};
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expert_module_t *expert_fb_zero;
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--
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GitLab
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