[ima-evm-utils PATCH 03/12] Update library function definitions to include a "public_keys" parameter

[Mimi Zohar <zohar@linux.ibm.com>]

Instead of relying on a global static "public_keys" variable, which is
not concurrency-safe, update static library function definitions to
include it as a parameter, define new library functions with it as
a parameter, and deprecate existing functions.

Define init_public_keys2(), verify_hash2(), and ima_verify_signature2()
functions. Update static function defintions to include "public_keys".

To avoid library incompatablity, make the existing functions -
init_public_keys(), verify_hash(), ima_verify_signature() - wrappers
for the new function versions.

Deprecate init_public_keys(), verify_hash(), ima_verify_signature()
functions.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 src/imaevm.h    |  2 ++
 src/libimaevm.c | 94 +++++++++++++++++++++++++++++++++++++------------
 2 files changed, 74 insertions(+), 22 deletions(-)

diff --git a/src/imaevm.h b/src/imaevm.h
index 828976e52881..146123ba5c42 100644
--- a/src/imaevm.h
+++ b/src/imaevm.h
@@ -249,8 +249,10 @@ uint32_t imaevm_read_keyid(const char *certfile);
 int sign_hash(const char *algo, const unsigned char *hash, int size, const char *keyfile, const char *keypass, unsigned char *sig);
 int verify_hash(const char *file, const unsigned char *hash, int size, unsigned char *sig, int siglen);
 int ima_verify_signature(const char *file, unsigned char *sig, int siglen, unsigned char *digest, int digestlen);
+int ima_verify_signature2(void *public_keys, const char *file, unsigned char *sig, int siglen, unsigned char *digest, int digestlen);
 void free_public_keys(void *public_keys);
 void init_public_keys(const char *keyfiles);
+int init_public_keys2(const char *keyfiles, void **public_keys);
 int imaevm_hash_algo_from_sig(unsigned char *sig);
 const char *imaevm_hash_algo_by_id(int algo);
 int calc_hash_sigv3(enum evm_ima_xattr_type type, const char *algo, const unsigned char *in_hash, unsigned char *out_hash);
diff --git a/src/libimaevm.c b/src/libimaevm.c
index 74e9d09b1f05..bf8c99770ddc 100644
--- a/src/libimaevm.c
+++ b/src/libimaevm.c
@@ -372,12 +372,12 @@ struct public_key_entry {
 };
 static struct public_key_entry *g_public_keys = NULL;
 
-static EVP_PKEY *find_keyid(uint32_t keyid)
+static EVP_PKEY *find_keyid(void *public_keys, uint32_t keyid)
 {
-	struct public_key_entry *entry, *tail = g_public_keys;
+	struct public_key_entry *entry, *tail = public_keys;
 	int i = 1;
 
-	for (entry = g_public_keys; entry != NULL; entry = entry->next) {
+	for (entry = public_keys; entry != NULL; entry = entry->next) {
 		if (entry->keyid == keyid)
 			return entry->key;
 		i++;
@@ -394,7 +394,7 @@ static EVP_PKEY *find_keyid(uint32_t keyid)
 	if (tail)
 		tail->next = entry;
 	else
-		g_public_keys = entry;
+		public_keys = (void *) entry;
 	log_err("key %d: %x (unknown keyid)\n", i, __be32_to_cpup(&keyid));
 	return 0;
 }
@@ -412,7 +412,7 @@ void free_public_keys(void *public_keys)
 	}
 }
 
-void init_public_keys(const char *keyfiles)
+int init_public_keys2(const char *keyfiles, void **public_keys)
 {
 	struct public_key_entry *entry;
 	char *tmp_keyfiles, *keyfiles_free;
@@ -420,6 +420,11 @@ void init_public_keys(const char *keyfiles)
 	int err = 0;
 	int i = 1;
 
+	if (!public_keys)
+		return -EINVAL;
+
+	*public_keys = NULL;
+
 	tmp_keyfiles = strdup(keyfiles);
 	keyfiles_free = tmp_keyfiles;
 
@@ -444,12 +449,24 @@ void init_public_keys(const char *keyfiles)
 		calc_keyid_v2(&entry->keyid, entry->name, entry->key);
 		sprintf(entry->name, "%x", __be32_to_cpup(&entry->keyid));
 		log_info("key %d: %s %s\n", i++, entry->name, keyfile);
-		entry->next = g_public_keys;
-		g_public_keys = entry;
+		entry->next = (struct public_key_entry *) *public_keys;
+		*public_keys = (void *)entry;
 	}
+
 	free(keyfiles_free);
 	if (err < 0)
-		free_public_keys(g_public_keys);
+		free_public_keys(public_keys);
+	return err;
+}
+
+/*
+ * Global static variables are not concurrency-safe.
+ *
+ * Deprecate init_public_keys() usage.
+ */
+void init_public_keys(const char *keyfiles)
+{
+	init_public_keys2(keyfiles, (void **)&g_public_keys);
 }
 
 /*
@@ -466,7 +483,8 @@ void init_public_keys(const char *keyfiles)
  *
  * (Note: signature_v2_hdr struct does not contain the 'type'.)
  */
-static int verify_hash_common(const char *file, const unsigned char *hash,
+static int verify_hash_common(void *public_keys, const char *file,
+			      const unsigned char *hash,
 			      int size, unsigned char *sig, int siglen)
 {
 	int ret = -1;
@@ -481,7 +499,7 @@ static int verify_hash_common(const char *file, const unsigned char *hash,
 		log_dump(hash, size);
 	}
 
-	pkey = find_keyid(hdr->keyid);
+	pkey = find_keyid(public_keys, hdr->keyid);
 	if (!pkey) {
 		uint32_t keyid = hdr->keyid;
 
@@ -543,11 +561,13 @@ err:
  *
  * Return: 0 verification good, 1 verification bad, -1 error.
  */
-static int verify_hash_v2(const char *file, const unsigned char *hash,
+static int verify_hash_v2(void *public_keys, const char *file,
+			  const unsigned char *hash,
 			  int size, unsigned char *sig, int siglen)
 {
 	/* note: signature_v2_hdr does not contain 'type', use sig + 1 */
-	return verify_hash_common(file, hash, size, sig + 1, siglen - 1);
+	return verify_hash_common(public_keys, file, hash, size,
+				  sig + 1, siglen - 1);
 }
 
 /*
@@ -556,7 +576,8 @@ static int verify_hash_v2(const char *file, const unsigned char *hash,
  *
  * Return: 0 verification good, 1 verification bad, -1 error.
  */
-static int verify_hash_v3(const char *file, const unsigned char *hash,
+static int verify_hash_v3(void *public_keys, const char *file,
+			  const unsigned char *hash,
 			  int size, unsigned char *sig, int siglen)
 {
 	unsigned char sigv3_hash[MAX_DIGEST_SIZE];
@@ -567,7 +588,8 @@ static int verify_hash_v3(const char *file, const unsigned char *hash,
 		return ret;
 
 	/* note: signature_v2_hdr does not contain 'type', use sig + 1 */
-	return verify_hash_common(file, sigv3_hash, size, sig + 1, siglen - 1);
+	return verify_hash_common(public_keys, file, sigv3_hash, size,
+				  sig + 1, siglen - 1);
 }
 
 #define HASH_MAX_DIGESTSIZE 64	/* kernel HASH_MAX_DIGESTSIZE is 64 bytes */
@@ -710,8 +732,9 @@ int imaevm_hash_algo_from_sig(unsigned char *sig)
 		return -1;
 }
 
-int verify_hash(const char *file, const unsigned char *hash, int size,
-		unsigned char *sig, int siglen)
+int verify_hash2(void *public_keys, const char *file,
+		 const unsigned char *hash, int size,
+		 unsigned char *sig, int siglen)
 {
 	/* Get signature type from sig header */
 	if (sig[1] == DIGSIG_VERSION_1) {
@@ -730,15 +753,29 @@ int verify_hash(const char *file, const unsigned char *hash, int size,
 		return -1;
 #endif
 	} else if (sig[1] == DIGSIG_VERSION_2) {
-		return verify_hash_v2(file, hash, size, sig, siglen);
+		return verify_hash_v2(public_keys, file, hash, size,
+				      sig, siglen);
 	} else if (sig[1] == DIGSIG_VERSION_3) {
-		return verify_hash_v3(file, hash, size, sig, siglen);
+		return verify_hash_v3(public_keys, file, hash, size,
+				      sig, siglen);
 	} else
 		return -1;
 }
 
-int ima_verify_signature(const char *file, unsigned char *sig, int siglen,
-			 unsigned char *digest, int digestlen)
+/*
+ * Global static variables are not concurrency-safe.
+ *
+ * Deprecate verify_hash() usage.
+ */
+int verify_hash(const char *file, const unsigned char *hash, int size,
+		unsigned char *sig, int siglen)
+{
+	return verify_hash2(g_public_keys, file, hash, size, sig, siglen);
+}
+
+int ima_verify_signature2(void *public_keys, const char *file,
+			  unsigned char *sig, int siglen,
+			  unsigned char *digest, int digestlen)
 {
 	unsigned char hash[MAX_DIGEST_SIZE];
 	int hashlen, sig_hash_algo;
@@ -766,14 +803,27 @@ int ima_verify_signature(const char *file, unsigned char *sig, int siglen,
 	 * measurement list, not by calculating the local file digest.
 	 */
 	if (digest && digestlen > 0)
-		return verify_hash(file, digest, digestlen, sig, siglen);
+		return verify_hash2(public_keys, file, digest, digestlen,
+				   sig, siglen);
 
 	hashlen = ima_calc_hash(file, hash);
 	if (hashlen <= 1)
 		return hashlen;
 	assert(hashlen <= sizeof(hash));
 
-	return verify_hash(file, hash, hashlen, sig, siglen);
+	return verify_hash2(public_keys, file, hash, hashlen, sig, siglen);
+}
+
+/*
+ * Global static variables are not concurrency-safe.
+ *
+ * Deprecate ima_verify_signature() usage.
+ */
+int ima_verify_signature(const char *file, unsigned char *sig, int siglen,
+			 unsigned char *digest, int digestlen)
+{
+	return ima_verify_signature2(g_public_keys, file, sig, siglen,
+				     digest, digestlen);
 }
 
 #if CONFIG_SIGV1
-- 
2.39.3