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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: 0e28bf61a5 ("KEYS: trusted: dcp: fix leak of blob encryption key")
Signed-off-by: David Gstir <david@sigma-star.at>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
pull/1131/head
David Gstir 2024-11-13 22:27:54 +01:00 committed by Jarkko Sakkinen
parent 5f56d41a21
commit e8d9fab39d
1 changed files with 18 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
security/keys/trusted-keys/trusted_dcp.c
View File

@ -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;
}