Added a fuzzer for SMIME

Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20332)

1 files changed, 49 insertions, 0 deletions

diff --git a/fuzz/smime.c b/fuzz/smime.c
new file mode 100644
index 0000000000..8a4deff2f6
--- /dev/null
+++ b/fuzz/smime.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * https://www.openssl.org/source/license.html
+ * or in the file LICENSE in the source distribution.
+ */
+
+#include "fuzzer.h"
+#include <openssl/err.h>
+#include <openssl/pkcs7.h>
+#include <openssl/x509.h>
+#include <stdio.h>
+
+int FuzzerInitialize(int *argc, char ***argv)
+{
+    return 1;
+}
+
+int FuzzerTestOneInput(const uint8_t *buf, size_t len)
+{
+    BIO *b = BIO_new_mem_buf(buf, len);
+    PKCS7 *p7 = SMIME_read_PKCS7(b, NULL);
+
+    if (p7 != NULL) {
+        STACK_OF(PKCS7_SIGNER_INFO) *p7si = PKCS7_get_signer_info(p7);
+        int i;
+
+        for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(p7si); i++) {
+            STACK_OF(X509_ALGOR) *algs;
+
+            PKCS7_cert_from_signer_info(p7,
+                                        sk_PKCS7_SIGNER_INFO_value(p7si, i));
+            algs = PKCS7_get_smimecap(sk_PKCS7_SIGNER_INFO_value(p7si, i));
+            sk_X509_ALGOR_pop_free(algs, X509_ALGOR_free);
+        }
+        PKCS7_free(p7);
+    }
+
+    BIO_free(b);
+    ERR_clear_error();
+    return 0;
+}
+
+void FuzzerCleanup(void)
+{
+}