[msan] Intercept getutent and friends

[vitalybuka]

LGTM

[kubamracek]

Darwin doesn't have utmp.h (it does have utmpx.h though). I'll #ifdef it out, okay?

[kubamracek]

Done in r289881.

[eugenis]

thank you!

lib/sanitizer_common/sanitizer_common_interceptors.inc

 }
 #define INIT___LXSTAT64 COMMON_INTERCEPT_FUNCTION(__lxstat64)
 #else
 #define INIT___LXSTAT64
 #endif
 
 // FIXME: add other *stat interceptor
 
+#if SANITIZER_INTERCEPT_UTMP
+INTERCEPTOR(void *, getutent, int dummy) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutent, dummy);
+  void *res = REAL(getutent)(dummy);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmp_sz);
+  return res;
+}
+INTERCEPTOR(void *, getutid, void *ut) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutid, ut);
+  void *res = REAL(getutid)(ut);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmp_sz);
+  return res;
+}
+INTERCEPTOR(void *, getutline, void *ut) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutline, ut);
+  void *res = REAL(getutline)(ut);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmp_sz);
+  return res;
+}
+#define INIT_UTMP                      \
+  COMMON_INTERCEPT_FUNCTION(getutent); \
+  COMMON_INTERCEPT_FUNCTION(getutid);  \
+  COMMON_INTERCEPT_FUNCTION(getutline);
+#else
+#define INIT_UTMP
+#endif
+
+#if SANITIZER_INTERCEPT_UTMPX
+INTERCEPTOR(void *, getutxent, int dummy) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutxent, dummy);
+  void *res = REAL(getutxent)(dummy);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmpx_sz);
+  return res;
+}
+INTERCEPTOR(void *, getutxid, void *ut) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutxid, ut);
+  void *res = REAL(getutxid)(ut);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmpx_sz);
+  return res;
+}
+INTERCEPTOR(void *, getutxline, void *ut) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, getutxline, ut);
+  void *res = REAL(getutxline)(ut);
+  if (res)
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, __sanitizer::struct_utmpx_sz);
+  return res;
+}
+#define INIT_UTMPX                      \
+  COMMON_INTERCEPT_FUNCTION(getutxent); \
+  COMMON_INTERCEPT_FUNCTION(getutxid);  \
+  COMMON_INTERCEPT_FUNCTION(getutxline);
+#else
+#define INIT_UTMPX
+#endif
+
 static void InitializeCommonInterceptors() {
   static u64 metadata_mem[sizeof(MetadataHashMap) / sizeof(u64) + 1];
   interceptor_metadata_map = new((void *)&metadata_mem) MetadataHashMap();
 
   INIT_TEXTDOMAIN;
   INIT_STRLEN;
   INIT_STRNLEN;
   INIT_STRCMP;
static void InitializeCommonInterceptors() {
   INIT_SEND_SENDTO;
   INIT_STAT;
   INIT_EVENTFD_READ_WRITE;
   INIT___XSTAT;
   INIT___XSTAT64;
   INIT___LXSTAT;
   INIT___LXSTAT64;
   // FIXME: add other *stat interceptors.
+  INIT_UTMP;
+  INIT_UTMPX;
 }

lib/sanitizer_common/sanitizer_platform_interceptors.h

 #define SANITIZER_INTERCEPT_SEND_SENDTO SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_EVENTFD_READ_WRITE SI_LINUX
 
 #define SANITIZER_INTERCEPT_STAT (SI_FREEBSD || SI_MAC || SI_ANDROID)
 #define SANITIZER_INTERCEPT___XSTAT !SANITIZER_INTERCEPT_STAT && SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT___XSTAT64 SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT___LXSTAT SANITIZER_INTERCEPT___XSTAT
 #define SANITIZER_INTERCEPT___LXSTAT64 SI_LINUX_NOT_ANDROID
+
+#define SANITIZER_INTERCEPT_UTMP SI_NOT_WINDOWS
+#define SANITIZER_INTERCEPT_UTMPX SI_LINUX_NOT_ANDROID || SI_MAC || SI_FREEBSD
+
 #endif  // #ifndef SANITIZER_PLATFORM_INTERCEPTORS_H

lib/sanitizer_common/sanitizer_platform_limits_posix.h

#if (SANITIZER_LINUX || SANITIZER_FREEBSD) && !SANITIZER_ANDROID
   extern unsigned struct_shminfo_sz;
   extern unsigned struct_shm_info_sz;
   extern int shmctl_ipc_stat;
   extern int shmctl_ipc_info;
   extern int shmctl_shm_info;
   extern int shmctl_shm_stat;
 #endif
 
+  extern unsigned struct_utmp_sz;
+#if !SANITIZER_ANDROID
+  extern unsigned struct_utmpx_sz;
+#endif
+
   extern int map_fixed;
 
   // ioctl arguments
   struct __sanitizer_ifconf {
     int ifc_len;
     union {
       void *ifcu_req;
     } ifc_ifcu;

lib/sanitizer_common/sanitizer_platform_limits_posix.cc

 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/times.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
 #include <termios.h>
 #include <time.h>
 #include <wchar.h>
+#include <utmp.h>
 
 #if !SANITIZER_IOS
 #include <net/route.h>
 #endif
 
 #if !SANITIZER_ANDROID
 #include <sys/mount.h>
 #include <sys/timeb.h>
+#include <utmpx.h>
 #endif
 
 #if SANITIZER_LINUX
 #include <malloc.h>
 #include <mntent.h>
 #include <netinet/ether.h>
 #include <sys/sysinfo.h>
 #include <sys/vt.h>
#if (SANITIZER_LINUX || SANITIZER_FREEBSD) && !SANITIZER_ANDROID
   unsigned struct_shminfo_sz = sizeof(struct shminfo);
   unsigned struct_shm_info_sz = sizeof(struct shm_info);
   int shmctl_ipc_stat = (int)IPC_STAT;
   int shmctl_ipc_info = (int)IPC_INFO;
   int shmctl_shm_info = (int)SHM_INFO;
   int shmctl_shm_stat = (int)SHM_STAT;
 #endif
 
+  unsigned struct_utmp_sz = sizeof(struct utmp);
+#if !SANITIZER_ANDROID
+  unsigned struct_utmpx_sz = sizeof(struct utmpx);
+#endif
+
   int map_fixed = MAP_FIXED;
 
   int af_inet = (int)AF_INET;
   int af_inet6 = (int)AF_INET6;
 
   uptr __sanitizer_in_addr_sz(int af) {
     if (af == AF_INET)
       return sizeof(struct in_addr);

test/msan/getutent.cc

+// RUN: %clangxx_msan -O0 -g %s -o %t && %run %t
+
+#include <utmp.h>
+#include <utmpx.h>
+#include <sanitizer/msan_interface.h>
+
+int main(void) {
+  setutent();
+  while (struct utmp *ut = getutent())
+    __msan_check_mem_is_initialized(ut, sizeof(*ut));
+  endutent();
+
+  setutxent();
+  while (struct utmpx *utx = getutxent())
+    __msan_check_mem_is_initialized(utx, sizeof(*utx));
+  endutxent();
+}