pkcs7: provide fuzz harness

This allows for pkcs7 fuzz testing with OSS-Fuzz.

Signed-off-by: Daniel Axtens <[email protected]>

programs/fuzz/CMakeLists.txt

@@ -28,6 +28,9 @@ if(NOT FUZZINGENGINE_LIB)
     add_executable(fuzz_pubkey fuzz_pubkey.c onefile.c)
     target_link_libraries(fuzz_pubkey ${libs})
 
+    add_executable(fuzz_pkcs7 fuzz_pkcs7.c onefile.c)
+    target_link_libraries(fuzz_pkcs7 ${libs})
+
     add_executable(fuzz_client fuzz_client.c common.c onefile.c)
     target_link_libraries(fuzz_client ${libs})
 
@@ -62,6 +65,10 @@ else()
     target_link_libraries(fuzz_pubkey ${libs} FuzzingEngine)
     SET_TARGET_PROPERTIES(fuzz_pubkey PROPERTIES LINKER_LANGUAGE CXX)
 
+    add_executable(fuzz_pkcs7 fuzz_pkcs7.c)
+    target_link_libraries(fuzz_pkcs7 ${libs} FuzzingEngine)
+    SET_TARGET_PROPERTIES(fuzz_pkcs7 PROPERTIES LINKER_LANGUAGE CXX)
+
     add_executable(fuzz_client fuzz_client.c common.c)
     target_link_libraries(fuzz_client ${libs} FuzzingEngine)
     SET_TARGET_PROPERTIES(fuzz_client PROPERTIES LINKER_LANGUAGE CXX)

programs/fuzz/fuzz_pkcs7.c

@@ -0,0 +1,19 @@
+#include <stdint.h>
+#include "mbedtls/pkcs7.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+#ifdef MBEDTLS_PKCS7_USE_C
+    mbedtls_pkcs7 pkcs7;
+
+    mbedtls_pkcs7_init( &pkcs7 );
+
+    mbedtls_pkcs7_parse_der( Data, Size, &pkcs7 );
+
+    mbedtls_pkcs7_free( &pkcs7 );
+#else
+    (void) Data;
+    (void) Size;
+#endif
+
+    return 0;
+}

programs/fuzz/fuzz_pkcs7.options

@@ -0,0 +1,2 @@
+[libfuzzer]
+max_len = 65535