[PATCH v12 06/10] x509: Detect sm2 keys by their parameters OID
From: Stefan Berger <stefanb@linux.ibm.com>
Date: 2021-03-16 21:08:56
Also in:
keyrings, linux-crypto, linux-integrity, lkml
Subsystem:
asymmetric keys, crypto api, library code, the rest · Maintainers:
David Howells, Lukas Wunner, Ignat Korchagin, Herbert Xu, "David S. Miller", Andrew Morton, Linus Torvalds
Detect whether a key is an sm2 type of key by its OID in the parameters array rather than assuming that everything under OID_id_ecPublicKey is sm2, which is not the case. Cc: David Howells <dhowells@redhat.com> Cc: keyrings@vger.kernel.org Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Tianjia Zhang <redacted> Tested-by: Tianjia Zhang <redacted> --- crypto/asymmetric_keys/x509_cert_parser.c | 12 +++++++++++- include/linux/oid_registry.h | 1 + lib/oid_registry.c | 24 +++++++++++++++++++++++ 3 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 52c9b455fc7d..1621ceaf5c95 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c@@ -459,6 +459,7 @@ int x509_extract_key_data(void *context, size_t hdrlen, const void *value, size_t vlen) { struct x509_parse_context *ctx = context; + enum OID oid; ctx->key_algo = ctx->last_oid; switch (ctx->last_oid) {
@@ -470,7 +471,16 @@ int x509_extract_key_data(void *context, size_t hdrlen, ctx->cert->pub->pkey_algo = "ecrdsa"; break; case OID_id_ecPublicKey: - ctx->cert->pub->pkey_algo = "sm2"; + if (parse_OID(ctx->params, ctx->params_size, &oid) != 0) + return -EBADMSG; + + switch (oid) { + case OID_sm2: + ctx->cert->pub->pkey_algo = "sm2"; + break; + default: + return -ENOPKG; + } break; default: return -ENOPKG;
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index b504e2f36b25..f32d91895e4d 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h@@ -121,6 +121,7 @@ enum OID { }; extern enum OID look_up_OID(const void *data, size_t datasize); +extern int parse_OID(const void *data, size_t datasize, enum OID *oid); extern int sprint_oid(const void *, size_t, char *, size_t); extern int sprint_OID(enum OID, char *, size_t);
diff --git a/lib/oid_registry.c b/lib/oid_registry.c
index f7ad43f28579..3dfaa836e7c5 100644
--- a/lib/oid_registry.c
+++ b/lib/oid_registry.c@@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/errno.h> #include <linux/bug.h> +#include <linux/asn1.h> #include "oid_registry_data.c" MODULE_DESCRIPTION("OID Registry");
@@ -92,6 +93,29 @@ enum OID look_up_OID(const void *data, size_t datasize) } EXPORT_SYMBOL_GPL(look_up_OID); +/** + * parse_OID - Parse an OID from a bytestream + * @data: Binary representation of the header + OID + * @datasize: Size of the binary representation + * @oid: Pointer to oid to return result + * + * Parse an OID from a bytestream that holds the OID in the format + * ASN1_OID | length | oid. The length indicator must equal to datasize - 2. + * -EBADMSG is returned if the bytestream is too short. + */ +int parse_OID(const void *data, size_t datasize, enum OID *oid) +{ + const unsigned char *v = data; + + /* we need 2 bytes of header and at least 1 byte for oid */ + if (datasize < 3 || v[0] != ASN1_OID || v[1] != datasize - 2) + return -EBADMSG; + + *oid = look_up_OID(data + 2, datasize - 2); + return 0; +} +EXPORT_SYMBOL_GPL(parse_OID); + /* * sprint_OID - Print an Object Identifier into a buffer * @data: The encoded OID to print
--
2.29.2