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fs-verity: don't pass whole descriptor to fsverity_verify_signature()

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Now that fsverity_get_descriptor() validates the sig_size field,
fsverity_verify_signature() doesn't need to do it.

Just change the prototype of fsverity_verify_signature() to take the
signature directly rather than take a fsverity_descriptor.

Link: https://lore.kernel.org/r/20210115181819.34732-3-ebiggers@kernel.org
Reviewed-by: Victor Hsieh <victorhsieh@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Amy Parker <enbyamy@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2021-01-15 10:18:15 -08:00 committed by Jaegeuk Kim
parent 28d8da556d
commit 3208a76b54
3 changed files with 10 additions and 19 deletions
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6
fs/verity/fsverity_private.h
View File

@ -140,15 +140,13 @@ void __init fsverity_exit_info_cache(void);
#ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES
int fsverity_verify_signature(const struct fsverity_info *vi,
const struct fsverity_descriptor *desc,
size_t desc_size);
const u8 *signature, size_t sig_size);
int __init fsverity_init_signature(void);
#else /* !CONFIG_FS_VERITY_BUILTIN_SIGNATURES */
static inline int
fsverity_verify_signature(const struct fsverity_info *vi,
const struct fsverity_descriptor *desc,
size_t desc_size)
const u8 *signature, size_t sig_size)
{
return 0;
}

3
fs/verity/open.c
View File

@ -181,7 +181,8 @@ struct fsverity_info *fsverity_create_info(const struct inode *inode,
vi->tree_params.hash_alg->name,
vi->tree_params.digest_size, vi->file_digest);
err = fsverity_verify_signature(vi, desc, desc_size);
err = fsverity_verify_signature(vi, desc->signature,
le32_to_cpu(desc->sig_size));
out:
if (err) {
fsverity_free_info(vi);

20
fs/verity/signature.c
View File

@ -29,21 +29,19 @@ static struct key *fsverity_keyring;
/**
* fsverity_verify_signature() - check a verity file's signature
* @vi: the file's fsverity_info
* @desc: the file's fsverity_descriptor
* @desc_size: size of @desc
* @signature: the file's built-in signature
* @sig_size: size of signature in bytes, or 0 if no signature
*
* If the file's fs-verity descriptor includes a signature of the file digest,
* verify it against the certificates in the fs-verity keyring.
* If the file includes a signature of its fs-verity file digest, verify it
* against the certificates in the fs-verity keyring.
*
* Return: 0 on success (signature valid or not required); -errno on failure
*/
int fsverity_verify_signature(const struct fsverity_info *vi,
const struct fsverity_descriptor *desc,
size_t desc_size)
const u8 *signature, size_t sig_size)
{
const struct inode *inode = vi->inode;
const struct fsverity_hash_alg *hash_alg = vi->tree_params.hash_alg;
const u32 sig_size = le32_to_cpu(desc->sig_size);
struct fsverity_formatted_digest *d;
int err;
@ -56,11 +54,6 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
return 0;
}
if (sig_size > desc_size - sizeof(*desc)) {
fsverity_err(inode, "Signature overflows verity descriptor");
return -EBADMSG;
}
d = kzalloc(sizeof(*d) + hash_alg->digest_size, GFP_KERNEL);
if (!d)
return -ENOMEM;
@ -70,8 +63,7 @@ int fsverity_verify_signature(const struct fsverity_info *vi,
memcpy(d->digest, vi->file_digest, hash_alg->digest_size);
err = verify_pkcs7_signature(d, sizeof(*d) + hash_alg->digest_size,
desc->signature, sig_size,
fsverity_keyring,
signature, sig_size, fsverity_keyring,
VERIFYING_UNSPECIFIED_SIGNATURE,
NULL, NULL);
kfree(d);