This is a note to let you know that I've just added the patch titled
KEYS: asymmetric: Copy sig and digest in public_key_verify_signature()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
keys-asymmetric-copy-sig-and-digest-in-public_key_ve.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5d8d6be6e6dbefd21b8bf9bf5b8aca9fad904491
Author: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Date: Thu Dec 8 10:56:46 2022 +0100
KEYS: asymmetric: Copy sig and digest in public_key_verify_signature()
[ Upstream commit c3d03e8e35e005e1a614e51bb59053eeb5857f76 ]
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: stable@xxxxxxxxxxxxxxx # 4.9.x
Fixes: ba14a194a434 ("fork: Add generic vmalloced stack support")
Link: https://lore.kernel.org/linux-integrity/Y4pIpxbjBdajymBJ@sol.localdomain/
Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Tested-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index e5fae4e838c06..2d57b0b3f9a4a 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -255,9 +255,10 @@ 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__);
@@ -281,28 +282,31 @@ 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;
- 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 |
@@ -310,8 +314,8 @@ 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:
