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Merge pull request #10615 from akallabeth/asn1-int

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[winpr,asn1] fix sign extraction for ASN1 integer
This commit is contained in:
Martin Fleisz
2024-09-17 11:08:53 +02:00
committed by GitHub
parent 6c88d89566 ca260e13bb
commit cd70c73e39
1 changed files with 13 additions and 7 deletions
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20
winpr/libwinpr/utils/asn1/asn1.c
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@@ -1023,22 +1023,28 @@ static size_t WinPrAsn1DecReadIntegerLike(WinPrAsn1Decoder* dec, WinPrAsn1_tag e
if (len == 0 || Stream_GetRemainingLength(&dec->source) < len || (len > 4))
return 0;
WinPrAsn1_INTEGER val = 0;
UINT32 uval = 0;
UINT8 v = 0;
Stream_Read_UINT8(&dec->source, v);
if (v & 0x80)
val = 0xFFFFFFFF;
val |= v;
/* extract sign from first byte.
* the ASN integer might be smaller than 32bit so we need to set the initial
* value to FF for all unused bytes (e.g. all except the lowest one we just read)
*/
BOOL isNegative = (v & 0x80);
if (isNegative)
uval = 0xFFFFFF00;
uval |= v;
for (size_t x = 1; x < len; x++)
{
Stream_Read_UINT8(&dec->source, v);
val = (WinPrAsn1_INTEGER)(((UINT32)val) << 8);
val |= v;
uval <<= 8;
uval |= v;
}
*target = val;
*target = (WinPrAsn1_INTEGER)uval;
ret += len;
/* TODO: check ber/der rules */