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FAILED: patch "[PATCH] KEYS: asymmetric: Copy sig and digest in" failed to apply to 4.19-stable tree

PATCH [email protected] 1 participant 1 message Jun 7, 2023

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Stable branch Crypto API Asymmetric keys
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The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x c3d03e8e35e005e1a614e51bb59053eeb5857f76
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023060747-echo-regain-c966@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c3d03e8e35e005e1a614e51bb59053eeb5857f76 Mon Sep 17 00:00:00 2001
From: Roberto Sassu <[email protected]>
Date: Thu, 8 Dec 2022 10:56:46 +0100
Subject: [PATCH] KEYS: asymmetric: Copy sig and digest in
public_key_verify_signature()

Commit ac4e97abce9b8 ("scatterlist: sg_set_buf() argument must be in linear mapping") checks that both the signature and the digest reside in the linear mapping area.

However, more recently commit ba14a194a434c ("fork: Add generic vmalloced stack support") made it possible to move the stack in the vmalloc area, which is not contiguous, and thus not suitable for sg_set_buf() which needs adjacent pages.

Always make a copy of the signature and digest in the same buffer used to store the key and its parameters, and pass them to sg_init_one(). Prefer it to conditionally doing the copy if necessary, to keep the code simple. The buffer allocated with kmalloc() is in the linear mapping area.

Cc [email protected] # 4.9.x
Fixes ba14a194a434 ("fork: Add generic vmalloced stack support")
Link https://lore.kernel.org/linux-integrity/[email protected]/ open here
Suggested-by Eric Biggers <[email protected]>
Signed-off-by Roberto Sassu <[email protected]>
Reviewed-by Eric Biggers <[email protected]>
Tested-by Stefan Berger <[email protected]>
crypto/asymmetric_keys/public_key.c +21 -17
index eca5671ad3f2..50c933f86b21 100644
@@ -380,9 +380,10 @@ int public_key_verify_signature(const struct public_key *pkey,
 	struct crypto_wait cwait;
 	struct crypto_akcipher *tfm;
 	struct akcipher_request *req;
-	struct scatterlist src_sg[2];
+	struct scatterlist src_sg;
 	char alg_name[CRYPTO_MAX_ALG_NAME];
-	char *key, *ptr;
+	char *buf, *ptr;
+	size_t buf_len;
 	int ret;
 
 	pr_devel("==>%s()\n", __func__);

@@ -420,34 +421,37 @@ int public_key_verify_signature(const struct public_key *pkey,
 	if (!req)
 		goto error_free_tfm;
 
-	key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
-		      GFP_KERNEL);
-	if (!key)
+	buf_len = max_t(size_t, pkey->keylen + sizeof(u32) * 2 + pkey->paramlen,
+			sig->s_size + sig->digest_size);
+
+	buf = kmalloc(buf_len, GFP_KERNEL);
+	if (!buf)
 		goto error_free_req;
 
-	memcpy(key, pkey->key, pkey->keylen);
-	ptr = key + pkey->keylen;
+	memcpy(buf, pkey->key, pkey->keylen);
+	ptr = buf + pkey->keylen;
 	ptr = pkey_pack_u32(ptr, pkey->algo);
 	ptr = pkey_pack_u32(ptr, pkey->paramlen);
 	memcpy(ptr, pkey->params, pkey->paramlen);
 
 	if (pkey->key_is_private)
-		ret = crypto_akcipher_set_priv_key(tfm, key, pkey->keylen);
+		ret = crypto_akcipher_set_priv_key(tfm, buf, pkey->keylen);
 	else
-		ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
+		ret = crypto_akcipher_set_pub_key(tfm, buf, pkey->keylen);
 	if (ret)
-		goto error_free_key;
+		goto error_free_buf;
 
 	if (strcmp(pkey->pkey_algo, "sm2") == 0 && sig->data_size) {
 		ret = cert_sig_digest_update(sig, tfm);
 		if (ret)
-			goto error_free_key;
+			goto error_free_buf;
 	}
 
-	sg_init_table(src_sg, 2);
-	sg_set_buf(&src_sg[0], sig->s, sig->s_size);
-	sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
-	akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size,
+	memcpy(buf, sig->s, sig->s_size);
+	memcpy(buf + sig->s_size, sig->digest, sig->digest_size);
+
+	sg_init_one(&src_sg, buf, sig->s_size + sig->digest_size);
+	akcipher_request_set_crypt(req, &src_sg, NULL, sig->s_size,
 				   sig->digest_size);
 	crypto_init_wait(&cwait);
 	akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |

@@ -455,8 +459,8 @@ int public_key_verify_signature(const struct public_key *pkey,
 				      crypto_req_done, &cwait);
 	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);
 
-error_free_key:
-	kfree(key);
+error_free_buf:
+	kfree(buf);
 error_free_req:
 	akcipher_request_free(req);
 error_free_tfm: