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avformat/jpegxl_probe: check length instead of blindly reading 

Enable the checked bitreader to avoid overread.
Also add a few checks in loops and between blocks so we exit instead of continued
execution.
Alternatively we could add manual checks so that no overread can happen. This would be
slightly faster but a bit more work and a bit more fragile

Fixes: Out of array accesses
Fixes: 59640/clusterfuzz-testcase-minimized-ffmpeg_dem_JPEGXL_ANIM_fuzzer-6584117345779712

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2023-06-08 10:26:34 -04:00 committed by Leo Izen
parent 25c937c0e0
commit 1ec4553e35
No known key found for this signature in database
GPG Key ID: 5A71C331FD2FA19A
1 changed files with 13 additions and 1 deletions
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14
libavformat/jpegxl_probe.c
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@ -21,6 +21,7 @@
#include "jpegxl_probe.h"
#define UNCHECKED_BITSTREAM_READER 0
#define BITSTREAM_READER_LE
#include "libavcodec/get_bits.h"
@ -293,6 +294,8 @@ int ff_jpegxl_verify_codestream_header(const uint8_t *buf, int buflen, int valid
skip_bits_long(gb, 1);
}
}
if (get_bits_left(gb) < 1)
return AVERROR_INVALIDDATA;
if (!all_default) {
jpegxl_skip_bit_depth(gb);
@ -307,6 +310,8 @@ int ff_jpegxl_verify_codestream_header(const uint8_t *buf, int buflen, int valid
for (uint32_t i = 0; i < num_extra_channels; i++) {
if (jpegxl_read_extra_channel_info(gb, validate_level) < 0)
return -1;
if (get_bits_left(gb) < 1)
return AVERROR_INVALIDDATA;
}
xyb_encoded = get_bits1(gb);
@ -336,8 +341,11 @@ int ff_jpegxl_verify_codestream_header(const uint8_t *buf, int buflen, int valid
return -1;
if (primaries == FF_JPEGXL_PR_CUSTOM) {
/* ux/uy values for r,g,b */
for (int i = 0; i < 6; i++)
for (int i = 0; i < 6; i++) {
jxl_u32(gb, 0, 524288, 1048576, 2097152, 19, 19, 20, 21);
if (get_bits_left(gb) < 1)
return AVERROR_INVALIDDATA;
}
}
}
}
@ -363,10 +371,14 @@ int ff_jpegxl_verify_codestream_header(const uint8_t *buf, int buflen, int valid
skip_bits_long(gb, 16 + 16 + 1 + 16);
extensions = jpegxl_u64(gb);
if (get_bits_left(gb) < 1)
return AVERROR_INVALIDDATA;
if (extensions) {
for (int i = 0; i < 64; i++) {
if (extensions & (UINT64_C(1) << i))
jpegxl_u64(gb);
if (get_bits_left(gb) < 1)
return AVERROR_INVALIDDATA;
}
}
}