From 46ae05dd174403d406fcfee2328a2b3b6f4c0eff Mon Sep 17 00:00:00 2001 From: Martin Willi Date: Wed, 13 Feb 2013 12:06:09 +0100 Subject: [PATCH] Remove leading zeros in SCEP certificate serialNumbers --- src/scepclient/scep.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/src/scepclient/scep.c b/src/scepclient/scep.c index 974eb9862..3fdcd6c28 100644 --- a/src/scepclient/scep.c +++ b/src/scepclient/scep.c @@ -151,8 +151,7 @@ void scep_generate_transaction_id(public_key_t *key, chunk_t *transID, chunk_t digest = chunk_alloca(HASH_SIZE_MD5); chunk_t keyEncoding = chunk_empty, keyInfo; hasher_t *hasher; - bool msb_set; - u_char *pos; + int zeros = 0, msb_set = 0; key->get_encoding(key, PUBKEY_ASN1_DER, &keyEncoding); @@ -168,20 +167,27 @@ void scep_generate_transaction_id(public_key_t *key, chunk_t *transID, DESTROY_IF(hasher); free(keyInfo.ptr); - /* is the most significant bit of the digest set? */ - msb_set = (*digest.ptr & 0x80) == 0x80; - - /* allocate space for the serialNumber */ - serialNumber->len = msb_set + digest.len; - serialNumber->ptr = malloc(serialNumber->len); - - /* the serial number as the two's complement of the digest */ - pos = serialNumber->ptr; + /* the serialNumber should be valid ASN1 integer content: + * remove leading zeros, add one if MSB is set (two's complement) */ + while (zeros < digest.len) + { + if (digest.ptr[zeros]) + { + if (digest.ptr[zeros] & 0x80) + { + msb_set = 1; + } + break; + } + zeros++; + } + *serialNumber = chunk_alloc(digest.len - zeros + msb_set); if (msb_set) { - *pos++ = 0x00; + serialNumber->ptr[0] = 0x00; } - memcpy(pos, digest.ptr, digest.len); + memcpy(serialNumber->ptr + msb_set, digest.ptr + zeros, + digest.len - zeros); /* the transaction id is the serial number in hex format */ *transID = chunk_to_hex(digest, NULL, TRUE);