From fb1188936ca29af61709afd8b866ea55d4a05a67 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 11 Dec 2025 15:02:28 +0000 Subject: [crypto] Generalise rsa_parse_integer() to asn1_enter_unsigned() ECDSA signature values and private keys are fixed-length unsigned integers modulo N (the group order of the elliptic curve) and are therefore most naturally represented in ASN.1 using ASN1_OCTET_STRING. Private key representations do use ASN1_OCTET_STRING, but signature values tend to use ASN1_INTEGER, which adds no value but does ensure that the encoding becomes variable-length and requires handling a pointless extra zero byte if the MSB of the unsigned value happens to be set. RSA also makes use of ASN1_INTEGER for modulus and exponent values. Generalise the existing rsa_parse_integer() to asn1_enter_unsigned() to allow this code to be reused for ECDSA. Signed-off-by: Michael Brown --- src/include/ipxe/asn1.h | 1 + 1 file changed, 1 insertion(+) (limited to 'src/include') diff --git a/src/include/ipxe/asn1.h b/src/include/ipxe/asn1.h index 641a1190d..914d42f57 100644 --- a/src/include/ipxe/asn1.h +++ b/src/include/ipxe/asn1.h @@ -488,6 +488,7 @@ extern int asn1_skip_any ( struct asn1_cursor *cursor ); extern int asn1_shrink_any ( struct asn1_cursor *cursor ); extern int asn1_enter_bits ( struct asn1_cursor *cursor, unsigned int *unused ); +extern int asn1_enter_unsigned ( struct asn1_cursor *cursor ); extern int asn1_boolean ( const struct asn1_cursor *cursor ); extern int asn1_integer ( const struct asn1_cursor *cursor, int *value ); extern int asn1_compare ( const struct asn1_cursor *cursor1, -- cgit v1.2.3-55-g7522