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From 3bf5eddb89afdf690eceaa52bc4d3546ba9a5f87 Mon Sep 17 00:00:00 2001
From: Eric Soroos <eric-github@soroos.net>
Date: Sun, 7 Mar 2021 12:32:12 +0100
Subject: [PATCH] Fix OOB Read in Jpeg2KDecode CVE-2021-25287,CVE-2021-25288
* For J2k images with multiple bands, it's legal in to have different
widths for each band, e.g. 1 byte for L, 4 bytes for A
* This dates to Pillow 2.4.0
--- pillow-8.1.2+dfsg.orig/src/libImaging/Jpeg2KDecode.c
+++ pillow-8.1.2+dfsg/src/libImaging/Jpeg2KDecode.c
@@ -589,7 +589,7 @@ j2k_decode_entry(Imaging im, ImagingCode
j2k_unpacker_t unpack = NULL;
size_t buffer_size = 0, tile_bytes = 0;
unsigned n, tile_height, tile_width;
- int components;
+ int total_component_width = 0;
stream = opj_stream_create(BUFFER_SIZE, OPJ_TRUE);
@@ -753,23 +753,40 @@ j2k_decode_entry(Imaging im, ImagingCode
goto quick_exit;
}
+ if (tile_info.nb_comps != image->numcomps) {
+ state->errcode = IMAGING_CODEC_BROKEN;
+ state->state = J2K_STATE_FAILED;
+ goto quick_exit;
+ }
+
/* Sometimes the tile_info.datasize we get back from openjpeg
- is less than numcomps*w*h, and we overflow in the
+ is less than sum(comp_bytes)*w*h, and we overflow in the
shuffle stage */
tile_width = tile_info.x1 - tile_info.x0;
tile_height = tile_info.y1 - tile_info.y0;
- components = tile_info.nb_comps == 3 ? 4 : tile_info.nb_comps;
- if (( tile_width > UINT_MAX / components ) ||
- ( tile_height > UINT_MAX / components ) ||
- ( tile_width > UINT_MAX / (tile_height * components )) ||
- ( tile_height > UINT_MAX / (tile_width * components ))) {
+
+ /* Total component width = sum (component_width) e.g, it's
+ legal for an la file to have a 1 byte width for l, and 4 for
+ a. and then a malicious file could have a smaller tile_bytes
+ */
+
+ for (n=0; n < tile_info.nb_comps; n++) {
+ // see csize /acsize calcs
+ int csize = (image->comps[n].prec + 7) >> 3;
+ csize = (csize == 3) ? 4 : csize;
+ total_component_width += csize;
+ }
+ if ((tile_width > UINT_MAX / total_component_width) ||
+ (tile_height > UINT_MAX / total_component_width) ||
+ (tile_width > UINT_MAX / (tile_height * total_component_width)) ||
+ (tile_height > UINT_MAX / (tile_width * total_component_width))) {
state->errcode = IMAGING_CODEC_BROKEN;
state->state = J2K_STATE_FAILED;
goto quick_exit;
}
-
- tile_bytes = tile_width * tile_height * components;
+
+ tile_bytes = tile_width * tile_height * total_component_width;
if (tile_bytes > tile_info.data_size) {
tile_info.data_size = tile_bytes;
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