From 7cc7ab73f83ee6d50dc9536bc3355495d8600fad Mon Sep 17 00:00:00 2001
From: Vitaly Chikunov <vt@altlinux.org>
Date: Thu, 21 Apr 2022 20:25:10 +0300
Subject: [PATCH] crypto: ecrdsa - Fix incorrect use of vli_cmp
Git-commit: 7cc7ab73f83ee6d50dc9536bc3355495d8600fad
Patch-mainline: v5.19-rc1
References: git-fixes

Correctly compare values that shall be greater-or-equal and not just
greater.

Fixes: 0d7a78643f69 ("crypto: ecrdsa - add EC-RDSA (GOST 34.10) algorithm")
Cc: <stable@vger.kernel.org>
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 crypto/ecrdsa.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/crypto/ecrdsa.c b/crypto/ecrdsa.c
index b32ffcaad9ad..f3c6b5e15e75 100644
--- 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 */
-- 
2.35.3