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author | David Howells <dhowells@redhat.com> | 2015-07-20 22:16:31 +0200 |
---|---|---|
committer | David Howells <dhowells@redhat.com> | 2015-08-12 18:01:00 +0200 |
commit | 2c7fd3675ef1867d0d0c39e9f0bb5ddb67bfc7a7 (patch) | |
tree | f76418aad41317e825944e4ca96657f489b13cb2 | |
parent | modsign: Add explicit CONFIG_SYSTEM_TRUSTED_KEYS option (diff) | |
download | linux-2c7fd3675ef1867d0d0c39e9f0bb5ddb67bfc7a7.tar.xz linux-2c7fd3675ef1867d0d0c39e9f0bb5ddb67bfc7a7.zip |
PKCS#7: Check content type and versions
We only support PKCS#7 signed-data [RFC2315 sec 9] content at the top level,
so reject anything else. Further, check that the version numbers in
SignedData and SignerInfo are 1 in both cases.
Note that we don't restrict the inner content type. In the PKCS#7 code we
don't parse the data attached there, but merely verify the signature over
it.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-By: David Woodhouse <David.Woodhouse@intel.com>
-rw-r--r-- | crypto/asymmetric_keys/pkcs7.asn1 | 6 | ||||
-rw-r--r-- | crypto/asymmetric_keys/pkcs7_parser.c | 75 |
2 files changed, 77 insertions, 4 deletions
diff --git a/crypto/asymmetric_keys/pkcs7.asn1 b/crypto/asymmetric_keys/pkcs7.asn1 index a5a14ef28c86..05504431e1c1 100644 --- a/crypto/asymmetric_keys/pkcs7.asn1 +++ b/crypto/asymmetric_keys/pkcs7.asn1 @@ -1,12 +1,12 @@ PKCS7ContentInfo ::= SEQUENCE { - contentType ContentType, + contentType ContentType ({ pkcs7_check_content_type }), content [0] EXPLICIT SignedData OPTIONAL } ContentType ::= OBJECT IDENTIFIER ({ pkcs7_note_OID }) SignedData ::= SEQUENCE { - version INTEGER, + version INTEGER ({ pkcs7_note_signeddata_version }), digestAlgorithms DigestAlgorithmIdentifiers, contentInfo ContentInfo, certificates CHOICE { @@ -68,7 +68,7 @@ SignerInfos ::= CHOICE { } SignerInfo ::= SEQUENCE { - version INTEGER, + version INTEGER ({ pkcs7_note_signerinfo_version }), issuerAndSerialNumber IssuerAndSerialNumber, digestAlgorithm DigestAlgorithmIdentifier ({ pkcs7_sig_note_digest_algo }), authenticatedAttributes CHOICE { diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c index 3bd5a1e4c493..ab427f04b299 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.c +++ b/crypto/asymmetric_keys/pkcs7_parser.c @@ -226,6 +226,79 @@ int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen, } /* + * We only support signed data [RFC2315 sec 9]. + */ +int pkcs7_check_content_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + if (ctx->last_oid != OID_signed_data) { + pr_warn("Only support pkcs7_signedData type\n"); + return -EINVAL; + } + + return 0; +} + +/* + * Note the SignedData version + */ +int pkcs7_note_signeddata_version(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + unsigned version; + + if (vlen != 1) + goto unsupported; + + version = *(const u8 *)value; + switch (version) { + case 1: + /* PKCS#7 SignedData [RFC2315 sec 9.1] */ + break; + default: + goto unsupported; + } + + return 0; + +unsupported: + pr_warn("Unsupported SignedData version\n"); + return -EINVAL; +} + +/* + * Note the SignerInfo version + */ +int pkcs7_note_signerinfo_version(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + unsigned version; + + if (vlen != 1) + goto unsupported; + + version = *(const u8 *)value; + switch (version) { + case 1: + /* PKCS#7 SignerInfo [RFC2315 sec 9.2] */ + break; + default: + goto unsupported; + } + + return 0; + +unsupported: + pr_warn("Unsupported SignerInfo version\n"); + return -EINVAL; +} + +/* * Extract a certificate and store it in the context. */ int pkcs7_extract_cert(void *context, size_t hdrlen, @@ -326,7 +399,7 @@ int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, } /* - * Note the set of auth attributes for digestion purposes [RFC2315 9.3] + * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3] */ int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, unsigned char tag, |