[PATCH v9 05/14] integrity: Introduce integrity_keyring_from_id()

From: Thiago Jung Bauermann
Date: Wed Dec 12 2018 - 21:11:28 EST


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@xxxxxxxxxxxxx>
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
---
security/integrity/digsig.c | 28 +++++++++++++++++++++-------
security/integrity/integrity.h | 6 ++++++
2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 71c3200521d6..bbfa3085d1b5 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -44,11 +44,10 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
#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] =
@@ -57,17 +56,32 @@ 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;
+
+ if (siglen < 2)
+ return -EINVAL;
+
+ keyring = integrity_keyring_from_id(id);
+ if (IS_ERR(keyring))
+ 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,
+ return digsig_verify(keyring, sig + 1, siglen - 1,
digest, digestlen);
case 2:
- return asymmetric_verify(keyring[id], sig, siglen,
+ return asymmetric_verify(keyring, sig, siglen,
digest, digestlen);
}

diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 2bf0fc51752b..6f657260a964 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -155,6 +155,7 @@ extern struct dentry *integrity_dir;

#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);

@@ -164,6 +165,11 @@ int __init integrity_load_cert(const unsigned int id, const char *source,
const void *data, size_t len, key_perm_t perm);
#else

+static inline struct key *integrity_keyring_from_id(const unsigned int id)
+{
+ return ERR_PTR(-EINVAL);
+}
+
static inline int integrity_digsig_verify(const unsigned int id,
const char *sig, int siglen,
const char *digest, int digestlen)