diff options
| author | John Thacker <johnthacker@gmail.com> | 2022-08-16 19:09:13 -0400 |
|---|---|---|
| committer | John Thacker <johnthacker@gmail.com> | 2022-08-17 07:52:39 +0000 |
| commit | b3c7c31124a71bf4d589597b7537d6862e34c33c (patch) | |
| tree | 9c9cce1df0e688b11dbbb85c6f32484cdedeb37b /epan | |
| parent | c725f356898abc41026c7c2ec6e4cb3bf22035a6 (diff) | |
tiff(file): Don't add a proto item when heuristics fail
Don't add the protocol to the tree if heuristics fail.
Make sure that we have enough bytes to perform the heuristics.
If the magic number is wrong, don't go on to retrieve the ifd offset.
Diffstat (limited to 'epan')
| -rw-r--r-- | epan/dissectors/file-tiff.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/epan/dissectors/file-tiff.c b/epan/dissectors/file-tiff.c index ae31ec1e97..46106e3639 100644 --- a/epan/dissectors/file-tiff.c +++ b/epan/dissectors/file-tiff.c @@ -802,8 +802,10 @@ static int dissect_tiff(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { int encoding; - proto_item *ti = proto_tree_add_item(tree, proto_tiff, tvb, 0, -1, ENC_NA); - proto_tree *tiff_tree = proto_item_add_subtree(ti, ett_tiff); + // Reject if we don't have enough room for the heuristics + if (tvb_captured_length(tvb) < 4) { + return 0; + } // Figure out if we're big-endian or little endian guint16 raw_encoding = tvb_get_ntohs(tvb, 0); @@ -819,17 +821,19 @@ dissect_tiff(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ } magic = tvb_get_guint16(tvb, 2, encoding); - ifd_offset = tvb_get_guint32(tvb, 4, encoding); // If the magic number isn't 42, abort with nothing decoded if (magic != 42) { return 0; } + proto_item *ti = proto_tree_add_item(tree, proto_tiff, tvb, 0, -1, ENC_NA); + proto_tree *tiff_tree = proto_item_add_subtree(ti, ett_tiff); + // Dissect the rest of the header proto_tree_add_item(tiff_tree, hf_tiff_header_endianness, tvb, 0, 2, encoding); proto_tree_add_item(tiff_tree, hf_tiff_header_magic, tvb, 2, 2, encoding); - proto_tree_add_item(tiff_tree, hf_tiff_header_lead_ifd, tvb, 4, 4, encoding); + proto_tree_add_item_ret_uint(tiff_tree, hf_tiff_header_lead_ifd, tvb, 4, 4, encoding, &ifd_offset); // Keep dissecting IFDs until the offset to the next one is zero while (ifd_offset != 0) { |