ima: Implement support for module-style appended signatures

Implement the appraise_type=imasig|modsig option, allowing IMA to read and
verify modsig signatures.

In case a file has both an xattr signature and an appended modsig, IMA will
only use the appended signature if the key used by the xattr signature
isn't present in the IMA or platform keyring.

Because modsig verification needs to convert from an integrity keyring id
to the keyring itself, add an integrity_keyring_from_id() function in
digsig.c so that integrity_modsig_verify() can use it.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Thiago Jung Bauermann
2019-06-27 23:19:30 -03:00
committed by Mimi Zohar
parent a5fbeb615c
commit 39b0709636
8 changed files with 209 additions and 23 deletions

View File

@@ -148,10 +148,13 @@ int integrity_kernel_read(struct file *file, loff_t offset,
extern struct dentry *integrity_dir;
struct modsig;
#ifdef CONFIG_INTEGRITY_SIGNATURE
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen);
int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
int __init integrity_init_keyring(const unsigned int id);
int __init integrity_load_x509(const unsigned int id, const char *path);
@@ -166,6 +169,12 @@ static inline int integrity_digsig_verify(const unsigned int id,
return -EOPNOTSUPP;
}
static inline int integrity_modsig_verify(unsigned int id,
const struct modsig *modsig)
{
return -EOPNOTSUPP;
}
static inline int integrity_init_keyring(const unsigned int id)
{
return 0;
@@ -191,6 +200,16 @@ static inline int asymmetric_verify(struct key *keyring, const char *sig,
}
#endif
#ifdef CONFIG_IMA_APPRAISE_MODSIG
int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
#else
static inline int ima_modsig_verify(struct key *keyring,
const struct modsig *modsig)
{
return -EOPNOTSUPP;
}
#endif
#ifdef CONFIG_IMA_LOAD_X509
void __init ima_load_x509(void);
#else