sha256.h: fix a buglet tiggered by empty augmented message.

Reported by Guido Vranken.
supranational · Mar 7, 2021 · 02d63da · 02d63da
1 parent 5ca026c
commit 02d63da
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/sha256.h b/src/sha256.h
@@ -64,7 +64,7 @@ static void sha256_update(SHA256_CTX *ctx, const void *_inp, size_t len)
 
     ctx->N += len;
 
-    if ((n = ctx->off) != 0) {
+    if ((len != 0) & ((n = ctx->off) != 0)) {
         size_t rem = sizeof(ctx->buf) - n;
 
         if (rem > len) {