Headline
CVE-2023-47470: avcodec/evc_ps: Check ref_pic_num and sps_max_dec_pic_buffering_minus1 · FFmpeg/FFmpeg@4565747
Buffer Overflow vulnerability in Ffmpeg before github commit 4565747056a11356210ed8edcecb920105e40b60 allows a remote attacker to achieve an out-of-array write, execute arbitrary code, and cause a denial of service (DoS) via the ref_pic_list_struct function in libavcodec/evc_ps.c
Expand Up
@@ -24,10 +24,14 @@
#define EXTENDED_SAR 255
// @see ISO_IEC_23094-1 (7.3.7 Reference picture list structure syntax)
static int ref_pic_list_struct(GetBitContext *gb, RefPicListStruct *rpl)
static int ref_pic_list_struct(EVCParserSPS *sps, GetBitContext *gb, RefPicListStruct *rpl)
{
uint32_t delta_poc_st, strp_entry_sign_flag = 0;
rpl->ref_pic_num = get_ue_golomb_long(gb);
if ((unsigned)rpl->ref_pic_num > sps->sps_max_dec_pic_buffering_minus1)
return AVERROR_INVALIDDATA;
if (rpl->ref_pic_num > 0) {
delta_poc_st = get_ue_golomb_long(gb);
Expand Down Expand Up
@@ -239,6 +243,8 @@ int ff_evc_parse_sps(GetBitContext *gb, EVCParamSets *ps)
sps->max_num_tid0_ref_pics = get_ue_golomb_31(gb);
else {
sps->sps_max_dec_pic_buffering_minus1 = get_ue_golomb_long(gb);
if ((unsigned)sps->sps_max_dec_pic_buffering_minus1 > 16 - 1)
return AVERROR_INVALIDDATA;
sps->long_term_ref_pic_flag = get_bits1(gb);
sps->rpl1_same_as_rpl0_flag = get_bits1(gb);
sps->num_ref_pic_list_in_sps[0] = get_ue_golomb(gb);
Expand All
@@ -248,17 +254,23 @@ int ff_evc_parse_sps(GetBitContext *gb, EVCParamSets *ps)
goto fail;
}
for (int i = 0; i < sps->num_ref_pic_list_in_sps[0]; ++i)
ref_pic_list_struct(gb, &sps->rpls[0][i]);
for (int i = 0; i < sps->num_ref_pic_list_in_sps[0]; ++i) {
ret = ref_pic_list_struct(sps, gb, &sps->rpls[0][i]);
if (ret < 0)
goto fail;
}
if (!sps->rpl1_same_as_rpl0_flag) {
sps->num_ref_pic_list_in_sps[1] = get_ue_golomb(gb);
if ((unsigned)sps->num_ref_pic_list_in_sps[1] >= EVC_MAX_NUM_RPLS) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
for (int i = 0; i < sps->num_ref_pic_list_in_sps[1]; ++i)
ref_pic_list_struct(gb, &sps->rpls[1][i]);
for (int i = 0; i < sps->num_ref_pic_list_in_sps[1]; ++i) {
ret = ref_pic_list_struct(sps, gb, &sps->rpls[1][i]);
if (ret < 0)
goto fail;
}
}
}
Expand Down