crypto: ecrdsa - Fix incorrect use of vli_cmp

Correctly compare values that shall be greater-or-equal and not just greater. Fixes: 0d7a786 ("crypto: ecrdsa - add EC-RDSA (GOST 34.10) algorithm") Cc: <[email protected]> Signed-off-by: Vitaly Chikunov <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
wafgo · Apr 29, 2022 · 7cc7ab7 · 7cc7ab7
1 parent 4ee4cda
commit 7cc7ab7
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/crypto/ecrdsa.c b/crypto/ecrdsa.c
@@ -113,15 +113,15 @@ static int ecrdsa_verify(struct akcipher_request *req)
 
 	/* Step 1: verify that 0 < r < q, 0 < s < q */
 	if (vli_is_zero(r, ndigits) ||
-	    vli_cmp(r, ctx->curve->n, ndigits) == 1 ||
+	    vli_cmp(r, ctx->curve->n, ndigits) >= 0 ||
 	    vli_is_zero(s, ndigits) ||
-	    vli_cmp(s, ctx->curve->n, ndigits) == 1)
+	    vli_cmp(s, ctx->curve->n, ndigits) >= 0)
 		return -EKEYREJECTED;
 
 	/* Step 2: calculate hash (h) of the message (passed as input) */
 	/* Step 3: calculate e = h \mod q */
 	vli_from_le64(e, digest, ndigits);
-	if (vli_cmp(e, ctx->curve->n, ndigits) == 1)
+	if (vli_cmp(e, ctx->curve->n, ndigits) >= 0)
 		vli_sub(e, e, ctx->curve->n, ndigits);
 	if (vli_is_zero(e, ndigits))
 		e[0] = 1;
@@ -137,7 +137,7 @@ static int ecrdsa_verify(struct akcipher_request *req)
 	/* Step 6: calculate point C = z_1P + z_2Q, and R = x_c \mod q */
 	ecc_point_mult_shamir(&cc, z1, &ctx->curve->g, z2, &ctx->pub_key,
 			      ctx->curve);
-	if (vli_cmp(cc.x, ctx->curve->n, ndigits) == 1)
+	if (vli_cmp(cc.x, ctx->curve->n, ndigits) >= 0)
 		vli_sub(cc.x, cc.x, ctx->curve->n, ndigits);
 
 	/* Step 7: if R == r signature is valid */