/*--------------------------------------------------------------------
* Check that a signature is good, leave state ready for append
*/
int
smp_chk_sign(struct smp_signctx *ctx)
{
struct SHA256Context cx;
unsigned char sign[SHA256_LEN];
int r = 0;
if (strncmp(ctx->id, ctx->ss->ident, sizeof ctx->ss->ident))
r = 1;
else if (ctx->unique != ctx->ss->unique)
r = 2;
else if ((uintptr_t)ctx->ss != ctx->ss->mapped)
r = 3;
else {
SHA256_Init(&ctx->ctx);
SHA256_Update(&ctx->ctx, ctx->ss,
offsetof(struct smp_sign, length));
SHA256_Update(&ctx->ctx, SIGN_DATA(ctx), ctx->ss->length);
cx = ctx->ctx;
SHA256_Update(&cx, &ctx->ss->length, sizeof(ctx->ss->length));
SHA256_Final(sign, &cx);
if (memcmp(sign, SIGN_END(ctx), sizeof sign))
r = 4;
}
if (r) {
fprintf(stderr, "CHK(%p %s %p %s) = %d\n",
ctx, ctx->id, ctx->ss,
r > 1 ? ctx->ss->ident : "<invalid>", r);
}
return (r);
}
/*--------------------------------------------------------------------
* Append data to a signature
*/
static void
smp_append_sign(struct smp_signctx *ctx, const void *ptr, uint32_t len)
{
struct VSHA256Context cx;
unsigned char sign[VSHA256_LEN];
if (len != 0) {
VSHA256_Update(&ctx->ctx, ptr, len);
ctx->ss->length += len;
}
cx = ctx->ctx;
VSHA256_Update(&cx, &ctx->ss->length, sizeof(ctx->ss->length));
VSHA256_Final(sign, &cx);
memcpy(SIGN_END(ctx), sign, sizeof sign);
}
