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Output value of avm_uleb_decode() is <= UINT32_MAX #5010

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Output value of avm_uleb_decode() is <= UINT32_MAX #5010

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4 changes: 2 additions & 2 deletions av2/decoder/obu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1320,11 +1320,11 @@ static size_t read_metadata_unit_header(AV2Decoder *pbi, const uint8_t *data,
AV2_COMMON *const cm = &pbi->common;
size_t type_length;
uint64_t type_value;
if (avm_uleb_decode(data, sz, &type_value, &type_length) < 0 ||
type_value > UINT32_MAX) {
if (avm_uleb_decode(data, sz, &type_value, &type_length) < 0) {
cm->error.error_code = AVM_CODEC_CORRUPT_FRAME;
return 0;
}
assert(type_value <= UINT32_MAX);
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@wantehchang wantehchang May 26, 2026

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The following code in avm_uleb_decode() ensures that type_value <= UINT32_MAX:

int avm_uleb_decode(const uint8_t *buffer, size_t available, uint64_t *value,
                    size_t *length) {
        ...

        // Fail on values larger than 32-bits to ensure consistent behavior on
        // 32 and 64 bit targets: value is typically used to determine buffer
        // allocation size.
        if (*value > UINT32_MAX) return -1;

        ...
}

metadata->type = (uint32_t)type_value;
size_t bytes_read = type_length;

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