| Message ID | 20180316203837.10174-7-bauerman@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
On Fri, 2018-03-16 at 17:38 -0300, Thiago Jung Bauermann wrote: > IMA will only look for a modsig if the xattr sig references a key which is > not in the expected kernel keyring. To that end, introduce > asymmetric_sig_has_known_key(). > > The logic of extracting the key used in the xattr sig is factored out from > asymmetric_verify() so that it can be used by the new function. > > Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> > --- > security/integrity/digsig_asymmetric.c | 44 +++++++++++++++++++++++++--------- > security/integrity/integrity.h | 8 +++++++ > 2 files changed, 41 insertions(+), 11 deletions(-) > > diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c > index ab6a029062a1..241647970c19 100644 > --- a/security/integrity/digsig_asymmetric.c > +++ b/security/integrity/digsig_asymmetric.c > @@ -79,26 +79,48 @@ static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid) > return key; > } > > -int asymmetric_verify(struct key *keyring, const char *sig, > - int siglen, const char *data, int datalen) > +static struct key *asymmetric_key_from_sig(struct key *keyring, const char *sig, > + int siglen) > { > - struct public_key_signature pks; > - struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; > - struct key *key; > - int ret = -ENOMEM; > + const struct signature_v2_hdr *hdr = (struct signature_v2_hdr *) sig; > > if (siglen <= sizeof(*hdr)) > - return -EBADMSG; > + return ERR_PTR(-EBADMSG); > > siglen -= sizeof(*hdr); > > if (siglen != be16_to_cpu(hdr->sig_size)) > - return -EBADMSG; > + return ERR_PTR(-EBADMSG); > > if (hdr->hash_algo >= HASH_ALGO__LAST) > - return -ENOPKG; > + return ERR_PTR(-ENOPKG); > + > + return request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); > +} > + > +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, > + int siglen) > +{ > + struct key *key; > + > + key = asymmetric_key_from_sig(keyring, sig, siglen); > + if (IS_ERR_OR_NULL(key)) > + return false; > + > + key_put(key); > + > + return true; > +} > + > +int asymmetric_verify(struct key *keyring, const char *sig, > + int siglen, const char *data, int datalen) > +{ > + struct public_key_signature pks; > + struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; > + struct key *key; > + int ret = -ENOMEM; > > - key = request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); > + key = asymmetric_key_from_sig(keyring, sig, siglen); > if (IS_ERR(key)) > return PTR_ERR(key); > > @@ -109,7 +131,7 @@ int asymmetric_verify(struct key *keyring, const char *sig, > pks.digest = (u8 *)data; > pks.digest_size = datalen; > pks.s = hdr->sig; > - pks.s_size = siglen; > + pks.s_size = siglen - sizeof(*hdr); > ret = verify_signature(key, &pks); > key_put(key); > pr_debug("%s() = %d\n", __func__, ret); > diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h > index 2d245f44ca26..4c381b992e11 100644 > --- a/security/integrity/integrity.h > +++ b/security/integrity/integrity.h > @@ -179,12 +179,20 @@ static inline int integrity_init_keyring(const unsigned int id) > #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS > int asymmetric_verify(struct key *keyring, const char *sig, > int siglen, const char *data, int datalen); > +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, > + int siglen); > #else > static inline int asymmetric_verify(struct key *keyring, const char *sig, > int siglen, const char *data, int datalen) > { > return -EOPNOTSUPP; > } > + > +static inline bool asymmetric_sig_has_known_key(struct key *keyring, > + const char *sig, int siglen) > +{ > + return false; > +} > #endif > > #ifdef CONFIG_IMA_LOAD_X509 >
diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c index ab6a029062a1..241647970c19 100644 --- a/security/integrity/digsig_asymmetric.c +++ b/security/integrity/digsig_asymmetric.c @@ -79,26 +79,48 @@ static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid) return key; } -int asymmetric_verify(struct key *keyring, const char *sig, - int siglen, const char *data, int datalen) +static struct key *asymmetric_key_from_sig(struct key *keyring, const char *sig, + int siglen) { - struct public_key_signature pks; - struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; - struct key *key; - int ret = -ENOMEM; + const struct signature_v2_hdr *hdr = (struct signature_v2_hdr *) sig; if (siglen <= sizeof(*hdr)) - return -EBADMSG; + return ERR_PTR(-EBADMSG); siglen -= sizeof(*hdr); if (siglen != be16_to_cpu(hdr->sig_size)) - return -EBADMSG; + return ERR_PTR(-EBADMSG); if (hdr->hash_algo >= HASH_ALGO__LAST) - return -ENOPKG; + return ERR_PTR(-ENOPKG); + + return request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); +} + +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, + int siglen) +{ + struct key *key; + + key = asymmetric_key_from_sig(keyring, sig, siglen); + if (IS_ERR_OR_NULL(key)) + return false; + + key_put(key); + + return true; +} + +int asymmetric_verify(struct key *keyring, const char *sig, + int siglen, const char *data, int datalen) +{ + struct public_key_signature pks; + struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; + struct key *key; + int ret = -ENOMEM; - key = request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); + key = asymmetric_key_from_sig(keyring, sig, siglen); if (IS_ERR(key)) return PTR_ERR(key); @@ -109,7 +131,7 @@ int asymmetric_verify(struct key *keyring, const char *sig, pks.digest = (u8 *)data; pks.digest_size = datalen; pks.s = hdr->sig; - pks.s_size = siglen; + pks.s_size = siglen - sizeof(*hdr); ret = verify_signature(key, &pks); key_put(key); pr_debug("%s() = %d\n", __func__, ret); diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 2d245f44ca26..4c381b992e11 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -179,12 +179,20 @@ static inline int integrity_init_keyring(const unsigned int id) #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS int asymmetric_verify(struct key *keyring, const char *sig, int siglen, const char *data, int datalen); +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, + int siglen); #else static inline int asymmetric_verify(struct key *keyring, const char *sig, int siglen, const char *data, int datalen) { return -EOPNOTSUPP; } + +static inline bool asymmetric_sig_has_known_key(struct key *keyring, + const char *sig, int siglen) +{ + return false; +} #endif #ifdef CONFIG_IMA_LOAD_X509
IMA will only look for a modsig if the xattr sig references a key which is not in the expected kernel keyring. To that end, introduce asymmetric_sig_has_known_key(). The logic of extracting the key used in the xattr sig is factored out from asymmetric_verify() so that it can be used by the new function. Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> --- security/integrity/digsig_asymmetric.c | 44 +++++++++++++++++++++++++--------- security/integrity/integrity.h | 8 +++++++ 2 files changed, 41 insertions(+), 11 deletions(-)