Correct the setitimer interceptor on NetBSD

[krytarowski]

Summary

itimerval can contain padding that may be legitimately uninitialized.

On NetBSD there are four integers of type "long, int, long, int", the
int argument stands for __sanitizer_suseconds_t. Compiler adds extra
padding in this layout.

Check every field of struct itimerval separately.

Define sanitizer_suseconds_t as long on FreeBSD, Linux and SmartOS,
and int on NetBSD. Define sanitizer_timeval and __sanitizer_itimerval.

Sponsored by <The NetBSD Foundation>

[krytarowski]

ping

lib/sanitizer_common/sanitizer_common_interceptors.inc

INTERCEPTOR(int, getitimer, int which, void *curr_value) {
   if (!res && curr_value) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, curr_value, struct_itimerval_sz);
   }
   return res;
 }
 INTERCEPTOR(int, setitimer, int which, const void *new_value, void *old_value) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, setitimer, which, new_value, old_value);
-  if (new_value)
-    COMMON_INTERCEPTOR_READ_RANGE(ctx, new_value, struct_itimerval_sz);
+  if (new_value) {
+    // itimerval can contain padding that may be legitimately uninitialized
+    const struct __sanitizer_itimerval *nv =
+        (const struct __sanitizer_itimerval *)new_value;
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, &nv->it_interval.tv_sec,
+                                  sizeof(__sanitizer_time_t));
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, &nv->it_interval.tv_usec,
+                                  sizeof(__sanitizer_suseconds_t));
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, &nv->it_value.tv_sec,
+                                  sizeof(__sanitizer_time_t));
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, &nv->it_value.tv_usec,
+                                  sizeof(__sanitizer_suseconds_t));
+  }
   // FIXME: under ASan the call below may write to freed memory and corrupt
   // its metadata. See
   // https://github.com/google/sanitizers/issues/321.
   int res = REAL(setitimer)(which, new_value, old_value);
   if (!res && old_value) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, old_value, struct_itimerval_sz);
   }
   return res;

lib/sanitizer_common/sanitizer_platform_limits_netbsd.h

struct __sanitizer_ifaddrs {
   void *ifa_dstaddr;  // (struct sockaddr *)
   void *ifa_data;
   unsigned int ifa_addrflags;
 };
 
 typedef unsigned __sanitizer_pthread_key_t;
 
 typedef long long __sanitizer_time_t;
+typedef int __sanitizer_suseconds_t;
+
+struct __sanitizer_timeval {
+  __sanitizer_time_t tv_sec;
+  __sanitizer_suseconds_t tv_usec;
+};
+
+struct __sanitizer_itimerval {
+  struct __sanitizer_timeval it_interval;
+  struct __sanitizer_timeval it_value;
+};
 
 struct __sanitizer_passwd {
   char *pw_name;
   char *pw_passwd;
   int pw_uid;
   int pw_gid;
   __sanitizer_time_t pw_change;
   char *pw_class;

lib/sanitizer_common/sanitizer_platform_limits_posix.h

#endif
   };
 
 #if defined(__x86_64__) && !defined(_LP64)
   typedef long long __sanitizer_time_t;
 #else
   typedef long __sanitizer_time_t;
 #endif
 
+  typedef long __sanitizer_suseconds_t;
+
+  struct __sanitizer_timeval {
+    __sanitizer_time_t tv_sec;
+    __sanitizer_suseconds_t tv_usec;
+  };
+
+  struct __sanitizer_itimerval {
+    struct __sanitizer_timeval it_interval;
+    struct __sanitizer_timeval it_value;
+  };
+
   struct __sanitizer_timeb {
     __sanitizer_time_t time;
     unsigned short millitm;
     short timezone;
     short dstflag;
   };
 
   struct __sanitizer_ether_addr {

lib/sanitizer_common/sanitizer_platform_limits_solaris.h

struct __sanitizer_group {
   char *gr_name;
   char *gr_passwd;
   int gr_gid;
   char **gr_mem;
 };
 
 typedef long __sanitizer_time_t;
 
+typedef long __sanitizer_suseconds_t;
+
+struct __sanitizer_timeval {
+  __sanitizer_time_t tv_sec;
+  __sanitizer_suseconds_t tv_usec;
+};
+
+struct __sanitizer_itimerval {
+  struct __sanitizer_timeval it_interval;
+  struct __sanitizer_timeval it_value;
+};
+
 struct __sanitizer_timeb {
   __sanitizer_time_t time;
   unsigned short millitm;
   short timezone;
   short dstflag;
 };
 
 struct __sanitizer_ether_addr {