avcodec/cbs_h265: don't attempt to read 0 length elements in sei_3d_reference_displays_info

Fixes: 70458/clusterfuzz-testcase-minimized-ffmpeg_BSF_TRACE_HEADERS_fuzzer-5259339779080192
Fixes: Assertion width > 0 && width <= 32 failed at libavcodec/cbs.c:608

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2024-08-01 13:17:07 -03:00
parent de7f999481
commit 4a56b5f3d8

View File

@ -2307,7 +2307,10 @@ SEI_FUNC(sei_3d_reference_displays_info, (CodedBitstreamContext *ctx, RWContext
else
length = FFMAX(0, (int)current->exponent_ref_display_width[i] +
(int)current->prec_ref_display_width - 31);
ubs(length, mantissa_ref_display_width[i], 1, i);
if (length)
ubs(length, mantissa_ref_display_width[i], 1, i);
else
infer(mantissa_ref_display_width[i], 0);
if (current->ref_viewing_distance_flag) {
us(6, exponent_ref_viewing_distance[i], 0, 62, 1, i);
if (!current->exponent_ref_viewing_distance[i])
@ -2315,7 +2318,10 @@ SEI_FUNC(sei_3d_reference_displays_info, (CodedBitstreamContext *ctx, RWContext
else
length = FFMAX(0, (int)current->exponent_ref_viewing_distance[i] +
(int)current->prec_ref_viewing_dist - 31);
ubs(length, mantissa_ref_viewing_distance[i], 1, i);
if (length)
ubs(length, mantissa_ref_viewing_distance[i], 1, i);
else
infer(mantissa_ref_viewing_distance[i], 0);
}
flags(additional_shift_present_flag[i], 1, i);
if (current->additional_shift_present_flag[i])