add fuzz_alpm_extract_keyid

meson.build

@@ -423,7 +423,16 @@ executable(
     c_args : ['-fsanitize=fuzzer,address', '-ggdb', '-O0', '-fno-omit-frame-pointer', '-DFUZZING_PACMAN'],
     link_args : ['-fsanitize=fuzzer,address', '-ggdb', '-O0', '-fno-omit-frame-pointer'],
 )
-
+# Note: this target must be built with clang!
+executable(
+    'fuzz_alpm_extract_keyid',
+    [fuzz_alpm_extract_keyid_sources, pacman_sources],
+    include_directories : includes,
+    link_with : [libalpm_a, libcommon],
+    dependencies : [],
+    c_args : ['-fsanitize=fuzzer,address', '-ggdb', '-O0', '-fno-omit-frame-pointer', '-DFUZZING_PACMAN'],
+    link_args : ['-fsanitize=fuzzer,address', '-ggdb', '-O0', '-fno-omit-frame-pointer'],
+)
 
 foreach wrapper : script_wrappers
   cdata = configuration_data()

src/fuzzing/fuzz_alpm_extract_keyid.c

@@ -0,0 +1,26 @@
+#define _XOPEN_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <wchar.h>
+
+/* libalpm */
+#include "alpm.h"
+#include "alpm_list.h"
+#include "handle.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+    if (Size == 0)
+        return 0;
+
+    alpm_handle_t handle;               // TODO/FIXME?
+    const char* filename = "/dev/null"; // TODO/FIXME?
+
+    alpm_list_t *keys = NULL;
+    alpm_extract_keyid(&handle, filename, /* sig */ Data, /* len */ Size, &keys);
+
+    return 0;
+}

src/fuzzing/meson.build

@@ -5,3 +5,7 @@ fuzz_wordsplit_sources = files('''
 fuzz_string_length_sources = files('''
   fuzz_string_length.c
 '''.split())
+
+fuzz_alpm_extract_keyid_sources = files('''
+  fuzz_alpm_extract_keyid.c
+'''.split())