Commit 63e93190 authored by Manuel Pégourié-Gonnard's avatar Manuel Pégourié-Gonnard
Browse files

Make a helpful constant public

parent b8cfe3f0
......@@ -30,6 +30,25 @@
#include "md.h"
#endif
/*
* RFC 4492 page 20:
*
* Ecdsa-Sig-Value ::= SEQUENCE {
* r INTEGER,
* s INTEGER
* }
*
* Size is at most
* 1 (tag) + 1 (len) + 1 (initial 0) + ECP_MAX_BYTES for each of r and s,
* twice that + 1 (tag) + 2 (len) for the sequence
* (assuming ECP_MAX_BYTES is less than 126 for r and s,
* and less than 124 (total len <= 255) for the sequence)
*/
#if POLARSSL_ECP_MAX_BYTES > 124
#error "POLARSSL_ECP_MAX_BYTES bigger than expected, please fix POLARSSL_ECDSA_MAX_LEN"
#endif
#define POLARSSL_ECDSA_MAX_LEN ( 3 + 2 * ( 3 + POLARSSL_ECP_MAX_BYTES ) )
/**
* \brief ECDSA context structure
*
......@@ -124,7 +143,7 @@ int ecdsa_verify( ecp_group *grp,
*
* \note The "sig" buffer must be at least as large as twice the
* size of the curve used, plus 7 (eg. 71 bytes if a 256-bit
* curve is used).
* curve is used). POLARSSL_ECDSA_MAX_LEN is always safe.
*
* \return 0 if successful,
* or a POLARSSL_ERR_ECP, POLARSSL_ERR_MPI or
......
......@@ -281,25 +281,6 @@ cleanup:
return( ret );
}
/*
* RFC 4492 page 20:
*
* Ecdsa-Sig-Value ::= SEQUENCE {
* r INTEGER,
* s INTEGER
* }
*
* Size is at most
* 1 (tag) + 1 (len) + 1 (initial 0) + ECP_MAX_BYTES for each of r and s,
* twice that + 1 (tag) + 2 (len) for the sequence
* (assuming ECP_MAX_BYTES is less than 126 for r and s,
* and less than 124 (total len <= 255) for the sequence)
*/
#if POLARSSL_ECP_MAX_BYTES > 124
#error "POLARSSL_ECP_MAX_BYTES bigger than expected, please fix MAX_SIG_LEN"
#endif
#define MAX_SIG_LEN ( 3 + 2 * ( 3 + POLARSSL_ECP_MAX_BYTES ) )
/*
* Convert a signature (given by context) to ASN.1
*/
......@@ -307,7 +288,7 @@ static int ecdsa_signature_to_asn1( ecdsa_context *ctx,
unsigned char *sig, size_t *slen )
{
int ret;
unsigned char buf[MAX_SIG_LEN];
unsigned char buf[POLARSSL_ECDSA_MAX_LEN];
unsigned char *p = buf + sizeof( buf );
size_t len = 0;
......
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