pkcs7: provide fuzz harness

This allows for pkcs7 fuzz testing with OSS-Fuzz.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
diff --git a/programs/fuzz/fuzz_pkcs7.options b/programs/fuzz/fuzz_pkcs7.options
new file mode 100644
index 0000000..0824b19
--- /dev/null
+++ b/programs/fuzz/fuzz_pkcs7.options
@@ -0,0 +1,2 @@
+[libfuzzer]
+max_len = 65535