[PATCH v5 14/18] integrity: Introduce integrity_keyring_from_id

Thiago Jung Bauermann
2017-10-18T00:57:00Z

IMA will need to obtain the keyring used to verify file signatures so that
it can verify the module-style signature appended to files.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
---
security/integrity/digsig.c | 28 +++++++++++++++++++---------
security/integrity/integrity.h | 1 +
2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 6f9e4ce568cd..935f1b3258e7 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -48,11 +48,10 @@ static bool init_keyring __initdata;
#define restrict_link_to_ima restrict_link_by_builtin_trusted
#endif

-int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
- const char *digest, int digestlen)
+struct key *integrity_keyring_from_id(const unsigned int id)
{
- if (id >= INTEGRITY_KEYRING_MAX || siglen < 2)
- return -EINVAL;
+ if (id >= INTEGRITY_KEYRING_MAX)
+ return ERR_PTR(-EINVAL);

if (!keyring[id]) {
keyring[id] =
@@ -61,18 +60,29 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
int err = PTR_ERR(keyring[id]);
pr_err("no %s keyring: %d\n", keyring_name[id], err);
keyring[id] = NULL;
- return err;
+ return ERR_PTR(err);
}
}

+ return keyring[id];
+}
+
+int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
+ const char *digest, int digestlen)
+{
+ struct key *keyring = integrity_keyring_from_id(id);
+
+ if (IS_ERR(keyring) || siglen < 2)
+ return PTR_ERR(keyring);
+
switch (sig[1]) {
case 1:
/* v1 API expect signature without xattr type */
- return digsig_verify(keyring[id], sig + 1, siglen - 1,
- digest, digestlen);
+ return digsig_verify(keyring, sig + 1, siglen - 1, digest,
+ digestlen);
case 2:
- return asymmetric_verify(keyring[id], sig, siglen,
- digest, digestlen);
+ return asymmetric_verify(keyring, sig, siglen, digest,
+ digestlen);
}

return -EOPNOTSUPP;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index dd7ac4bfc89a..657ce4558984 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -132,6 +132,7 @@ int integrity_kernel_read(struct file *file, loff_t offset,

#ifdef CONFIG_INTEGRITY_SIGNATURE

+struct key *integrity_keyring_from_id(const unsigned int id);
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen);