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ASN template: compile option to allow leading zeros

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DER/BER encoding requires positive numbers to not have leading zeros.

Sometimes customer's have examples that break the rules.
In those cases define: WOLFSSL_ASN_INT_LEAD_0_ANY
Define used in original ASN.1 implementation.
This commit is contained in:
Sean Parkinson
2023-03-13 08:16:44 +10:00
parent e8828574ea
commit 1d0b04bfb3
1 changed files with 4 additions and 6 deletions
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10
wolfcrypt/src/asn.c
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@ -1027,27 +1027,25 @@ static int GetASN_Integer(const byte* input, word32 idx, int length,
(defined(HAVE_FIPS_VERSION) && (HAVE_FIPS_VERSION > 2))
/* Check contents consist of one or more octets. */
if (length == 0) {
#ifdef WOLFSSL_DEBUG_ASN_TEMPLATE
WOLFSSL_MSG("Zero length INTEGER not allowed");
#endif
return ASN_PARSE_E;
}
#endif
if (input[idx] == 0) {
/* Check leading zero byte required. */
if ((length > 1) && ((input[idx + 1] & 0x80) == 0)) {
#ifdef WOLFSSL_DEBUG_ASN_TEMPLATE
WOLFSSL_MSG("Zero not required on INTEGER");
#endif
#ifndef WOLFSSL_ASN_INT_LEAD_0_ANY
return ASN_PARSE_E;
#endif
}
}
/* Check whether a leading zero byte was required. */
else if (positive && (input[idx] & 0x80)) {
#ifdef WOLFSSL_DEBUG_ASN_TEMPLATE
WOLFSSL_MSG("INTEGER is negative");
#endif
#ifndef WOLFSSL_ASN_INT_LEAD_0_ANY
return ASN_EXPECT_0_E;
#endif /* WOLFSSL_ASN_INT_LEAD_0_ANY */
}
return 0;