[Bug sanitizer/62089] New: Sanitizer may fail to instrument struct accesses

[y.gribov at samsung dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62089

            Bug ID: 62089
           Summary: Sanitizer may fail to instrument struct accesses
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: y.gribov at samsung dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org

Asan does not emit memory checks in copy_fs_struct function and thus fails to
detect invalid access (the code based upon fs_struct.c from Linux kernel):

#include <sanitizer/asan_interface.h>

struct vfsmount {};
struct dentry {};

struct path {
  struct vfsmount *mnt;
  struct dentry *dentry;
};

struct fs_struct {
  int users;
  int lock;
  int seq;
  int umask;
  int in_exec;
  struct path root, pwd;
};

void __attribute__((noinline, noclone))
copy_fs_struct(struct fs_struct *a, struct fs_struct *b) {
  a->root = b->root;
}

struct fs_struct a, b;

int
main () {
  __asan_poison_memory_region (&a.root, sizeof (a.root));
  copy_fs_struct (&a, &b);
  return 0;
}