Commit e8d9fab3 authored by David Gstir's avatar David Gstir Committed by Jarkko Sakkinen
Browse files

KEYS: trusted: dcp: fix improper sg use with CONFIG_VMAP_STACK=y 



With vmalloc stack addresses enabled (CONFIG_VMAP_STACK=y) DCP trusted
keys can crash during en- and decryption of the blob encryption key via
the DCP crypto driver. This is caused by improperly using sg_init_one()
with vmalloc'd stack buffers (plain_key_blob).

Fix this by always using kmalloc() for buffers we give to the DCP crypto
driver.

Cc: stable@vger.kernel.org # v6.10+
Fixes: 0e28bf61 ("KEYS: trusted: dcp: fix leak of blob encryption key")
Signed-off-by: default avatarDavid Gstir <david@sigma-star.at>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent 5f56d41a

security/keys/trusted-keys/trusted_dcp.c

+18 −4
Original line number Diff line number Diff line
@@ -201,12 +201,16 @@ static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob) 
{

	struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob;

	int blen, ret;

	u8 plain_blob_key[AES_KEYSIZE_128];

	u8 *plain_blob_key;



	blen = calc_blob_len(p->key_len);

	if (blen > MAX_BLOB_SIZE)

		return -E2BIG;



	plain_blob_key = kmalloc(AES_KEYSIZE_128, GFP_KERNEL);

	if (!plain_blob_key)

		return -ENOMEM;



	b->fmt_version = DCP_BLOB_VERSION;

	get_random_bytes(b->nonce, AES_KEYSIZE_128);

	get_random_bytes(plain_blob_key, AES_KEYSIZE_128);
@@ -229,7 +233,8 @@ static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob) 
	ret = 0;



out:

	memzero_explicit(plain_blob_key, sizeof(plain_blob_key));

	memzero_explicit(plain_blob_key, AES_KEYSIZE_128);

	kfree(plain_blob_key);



	return ret;

}
@@ -238,7 +243,7 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) 
{

	struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob;

	int blen, ret;

	u8 plain_blob_key[AES_KEYSIZE_128];

	u8 *plain_blob_key = NULL;



	if (b->fmt_version != DCP_BLOB_VERSION) {

		pr_err("DCP blob has bad version: %i, expected %i\n",
@@ -256,6 +261,12 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) 
		goto out;

	}



	plain_blob_key = kmalloc(AES_KEYSIZE_128, GFP_KERNEL);

	if (!plain_blob_key) {

		ret = -ENOMEM;

		goto out;

	}



	ret = decrypt_blob_key(b->blob_key, plain_blob_key);

	if (ret) {

		pr_err("Unable to decrypt blob key: %i\n", ret);
@@ -271,7 +282,10 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) 


	ret = 0;

out:

	memzero_explicit(plain_blob_key, sizeof(plain_blob_key));

	if (plain_blob_key) {

		memzero_explicit(plain_blob_key, AES_KEYSIZE_128);

		kfree(plain_blob_key);

	}



	return ret;

}