Change size of preallocated buffer for pk_sign() calls
diff --git a/library/x509write_csr.c b/library/x509write_csr.c
index d59354d..a73a1a0 100644
--- a/library/x509write_csr.c
+++ b/library/x509write_csr.c
@@ -43,11 +43,22 @@
#include "mbedtls/pem.h"
#endif
+
/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
+/*
+ * For the currently used signature algorithms the buffer to store any signature
+ * must be at least of size MAX(MBEDTLS_ECDSA_MAX_LEN, MBEDTLS_MPI_MAX_SIZE)
+ */
+#if MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_MPI_MAX_SIZE
+#define SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN
+#else
+#define SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE
+#endif
+
void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )
{
memset( ctx, 0, sizeof( mbedtls_x509write_csr ) );
@@ -163,7 +174,7 @@
size_t sig_oid_len = 0;
unsigned char *c, *c2;
unsigned char hash[64];
- unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
+ unsigned char sig[SIGNATURE_MAX_SIZE];
unsigned char tmp_buf[2048];
size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
size_t len = 0;