| Message ID | 20221227094632.2797203-2-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4,1/2] lib/mpi: Fix buffer overrun when SG is too long | expand |
On 12/27/2022 10:46 AM, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > 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_set_buf(). 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@vger.kernel.org # 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@kernel.org> > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > --- > crypto/asymmetric_keys/public_key.c | 39 ++++++++++++++++------------- > 1 file changed, 22 insertions(+), 17 deletions(-) > > diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c > index 2f8352e88860..a479e32cb280 100644 > --- a/crypto/asymmetric_keys/public_key.c > +++ b/crypto/asymmetric_keys/public_key.c > @@ -360,9 +360,10 @@ 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__); > @@ -400,34 +401,38 @@ 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_table(&src_sg, 1); > + sg_set_buf(&src_sg, buf, sig->s_size + sig->digest_size); Ops, didn't commit the changes. Will send a new version soon. Roberto > + 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 | > @@ -435,8 +440,8 @@ 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:
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index 2f8352e88860..a479e32cb280 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -360,9 +360,10 @@ 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__); @@ -400,34 +401,38 @@ 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_table(&src_sg, 1); + sg_set_buf(&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 | @@ -435,8 +440,8 @@ 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: