fail to compiling libqasan with NDK

[andreafioraldi]

fail to compiling libqasan with NDK

[andreafioraldi]

The errors seems quite clear. You have to hook __bionic_bzero instead of bzero (just change the function name) and replace void with const void in malloc_usable_size.
I didn't build libqasan with android in mind, but if this solves your usecase I can push a simple patch.

[andreafioraldi]

Pull again and test if now works.

[wuk0n9]

thanks for the patch, and there are some error in my test:

/home/zero/Documents/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android29-clang  -fPIC -shared -I ../include libqasan.c hooks.c malloc.c string.c uninstrument.c patch.c -o libqasan.so -ldl -pthread
hooks.c:177:22: error: invalid application of 'sizeof' to an incomplete type 'FILE' (aka 'struct __sFILE')
  QASAN_LOAD(stream, sizeof(FILE));
                     ^     ~~~~~~
../include/qasan.h:243:45: note: expanded from macro 'QASAN_LOAD'
  QASAN_CALL2(QASAN_ACTION_CHECK_LOAD, ptr, len)
                                            ^~~
../include/qasan.h:236:43: note: expanded from macro 'QASAN_CALL2'
  syscall(QASAN_FAKESYS_NR, action, arg1, arg2, NULL)
                                          ^~~~
/home/zero/Documents/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/stdio.h:58:8: note: forward declaration of 'struct __sFILE'
struct __sFILE;
       ^
hooks.c:300:6: error: redefinition of '__bionic_bzero'
void __bionic_bzero(void *s, size_t n) {
     ^
/home/zero/Documents/android-ndk-r21b/toolchains/llvm/prebuilt/linux-x86_64/bin/../sysroot/usr/include/strings.h:62:40: note: previous definition is here
static __inline__ __always_inline void __bionic_bzero(void* b, size_t len) {
                                       ^
2 errors generated.

it seem that __bionic_bzero is inline func in NDK, I don't know if it still work by hook __bionic_bzero .

[wuk0n9]

checked that symbol "bzero" is not in NDK's lib, I think maybe there is no need to hook bzero func in NDK .
I removed bzero part on hook.c ， the code pass compile and seem stable at fuzzing by now.

And I removed 'sizeof(FILE)' line in fgets func to pass compile .

char *fgets(char *s, int size, FILE *stream) {

  void *rtv = __builtin_return_address(0);

  QASAN_DEBUG("%14p: fgets(%p, %d, %p)\n", rtv, s, size, stream);
  QASAN_STORE(s, size);
  //QASAN_LOAD(stream, sizeof(FILE));
  char *r = __lq_libc_fgets(s, size, stream);
  QASAN_DEBUG("\t\t = %p\n", r);
  return r;
}

qasan will lost memory read record about the FILE struct when deal with fgets func,and I wonder if we can replace sizeof(FILE) with some const int when using NDK?

[andreafioraldi]

Problably you should find the header that defines FILE and include it when __BIONIC is defined. If you get it working, please do a PR.