tools/fuzz: add AFL stub program for x86 insn emulator fuzzer

This is a basic program to call into the unified fuzzing function.

Hook it up into build system so that we can always build test it.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

.gitignore

@@ -147,6 +147,7 @@ tools/flask/utils/flask-setenforce
 tools/flask/utils/flask-set-bool
 tools/flask/utils/flask-label-pci
 tools/fuzz/x86_instruction_emulator/x86_emulate*
+tools/fuzz/x86_instruction_emulator/afl-x86-insn-emulator-fuzzer
 tools/helpers/_paths.h
 tools/helpers/init-xenstore-domain
 tools/helpers/xen-init-dom0

tools/fuzz/x86_instruction_emulator/Makefile

@@ -3,7 +3,7 @@ include $(XEN_ROOT)/tools/Rules.mk
 
 .PHONY: x86-instruction-emulator-fuzzer-all
 ifeq ($(CONFIG_X86_64),y)
-x86-instruction-emulator-fuzzer-all: x86-insn-emulator.a x86-insn-emulator-fuzzer.o
+x86-instruction-emulator-fuzzer-all: x86-insn-emulator.a x86-insn-emulator-fuzzer.o afl
 else
 x86-instruction-emulator-fuzzer-all:
 endif
@@ -23,6 +23,8 @@ x86-insn-emulator-fuzzer.o: x86_emulate.h x86_emulate/x86_emulate.h
 x86-insn-emulator.a: x86_emulate.o
 	$(AR) rc $@ $^
 
+afl-x86-insn-emulator-fuzzer: afl-x86-insn-emulator-fuzzer.o x86-insn-emulator-fuzzer.o x86_emulate.o
+
 # Common targets
 .PHONY: all
 all: x86-instruction-emulator-fuzzer-all
@@ -33,7 +35,10 @@ distclean: clean
 
 .PHONY: clean
 clean:
-	rm -f *.a *.o
+	rm -f *.a *.o *-x86-insn-emulator-fuzzer
 
 .PHONY: install
 install: all
+
+.PHONY: afl
+afl: afl-x86-insn-emulator-fuzzer

tools/fuzz/x86_instruction_emulator/afl-x86-insn-emulator-fuzzer.c

@@ -0,0 +1,57 @@
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int LLVMFuzzerTestOneInput(const uint8_t *data_p, size_t size);
+
+#define INPUT_SIZE  4096
+static uint8_t input[INPUT_SIZE];
+
+int main(int argc, char **argv)
+{
+    size_t size;
+    FILE *fp;
+
+    if ( argc != 2 )
+    {
+        printf("Expecting only one argument\n");
+        exit(-1);
+    }
+
+    fp = fopen(argv[1], "rb");
+    if ( fp == NULL )
+    {
+        perror("fopen");
+        exit(-1);
+    }
+
+    size = fread(input, 1, INPUT_SIZE, fp);
+
+    if ( ferror(fp) )
+    {
+        perror("fread");
+        exit(-1);
+    }
+
+    if ( !feof(fp) )
+    {
+        printf("Input too large\n");
+        exit(-1);
+    }
+
+    fclose(fp);
+
+    LLVMFuzzerTestOneInput(input, size);
+
+    return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */