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author | Přemysl Eric Janouch <p@janouch.name> | 2023-05-22 20:48:59 +0200 |
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committer | Přemysl Eric Janouch <p@janouch.name> | 2023-05-22 20:56:28 +0200 |
commit | dba728e0c4ddcb2fda91b019ab420b6081757c2e (patch) | |
tree | c9fd6a8e250c4c618e6a490a8bfd8f3af9a2b35d /tools | |
parent | 544722f8e01a6408db00aecdcec4d842e481b7e2 (diff) | |
download | fiv-dba728e0c4ddcb2fda91b019ab420b6081757c2e.tar.gz fiv-dba728e0c4ddcb2fda91b019ab420b6081757c2e.tar.xz fiv-dba728e0c4ddcb2fda91b019ab420b6081757c2e.zip |
Improve TIFF handling within tools
Nikon NEFs violate TIFF Tech Note 1, and it is easy to detect.
Also guard against more pointer overflows, and fix a temporary array
being used outside of its scope (found by a compiler).
Diffstat (limited to 'tools')
-rw-r--r-- | tools/info.h | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/tools/info.h b/tools/info.h index 816c9cf..3853ae9 100644 --- a/tools/info.h +++ b/tools/info.h @@ -96,8 +96,9 @@ struct tiffer { static bool tiffer_u32(struct tiffer *self, uint32_t *u) { - if (self->p + 4 > self->end) + if (self->p < self->begin || self->p + 4 > self->end) return false; + *u = self->un->u32(self->p); self->p += 4; return true; @@ -106,8 +107,9 @@ tiffer_u32(struct tiffer *self, uint32_t *u) static bool tiffer_u16(struct tiffer *self, uint16_t *u) { - if (self->p + 2 > self->end) + if (self->p < self->begin || self->p + 2 > self->end) return false; + *u = self->un->u16(self->p); self->p += 2; return true; @@ -403,22 +405,35 @@ add_error(jv o, const char *message) static jv parse_exif_ifd(struct tiffer *T, const struct tiff_entry *info); +static bool +parse_exif_subifds_entry(struct tiffer *T, const struct tiffer_entry *entry, + struct tiffer *subT) +{ + int64_t offset = 0; + return tiffer_integer(T, entry, &offset) && + offset >= 0 && offset <= UINT32_MAX && tiffer_subifd(T, offset, subT); +} + static jv -parse_exif_subifds(struct tiffer *T, const struct tiffer_entry *entry, +parse_exif_subifds(struct tiffer *T, struct tiffer_entry *entry, struct tiff_entry *info) { - int64_t offset = 0; struct tiffer subT = {}; - if (!tiffer_integer(T, entry, &offset) || - offset < 0 || offset > UINT32_MAX || !tiffer_subifd(T, offset, &subT)) + if (!parse_exif_subifds_entry(T, entry, &subT)) return jv_null(); - // The chain should correspond to the values in the entry - // (TIFF Technical Note 1), we are not going to verify it. - // Note that Nikon NEFs do not follow this rule. jv a = jv_array(); do a = jv_array_append(a, parse_exif_ifd(&subT, info)); while (tiffer_next_ifd(&subT)); + + // The chain should correspond to the values in the entry (see TIFF + // Technical Note 1: "the NextIFD value of Child #1 must point to Child #2, + // and so on"), but at least some Nikon NEFs do not follow this rule. + if (jv_array_length(jv_copy(a)) == 1) { + while (tiffer_next_value(entry) && + parse_exif_subifds_entry(T, entry, &subT)) + a = jv_array_append(a, parse_exif_ifd(&subT, info)); + } return a; } @@ -475,8 +490,9 @@ static jv parse_exif_entry(jv o, struct tiffer *T, struct tiffer_entry *entry, const struct tiff_entry *info) { + static struct tiff_entry empty[] = {{}}; if (!info) - info = (struct tiff_entry[]) {{}}; + info = empty; for (; info->name; info++) if (info->tag == entry->tag) |