From d7bead833631486e337e541e692d9b4a1ca14edd Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Fri, 28 Apr 2023 09:59:17 -0700
Subject: [PATCH] [sanitizer] Remove crypt and crypt_r interceptors

From Florian Weimer's D144073

> On GNU/Linux (glibc), the crypt and crypt_r functions are not part of the main shared object (libc.so.6), but libcrypt (with multiple possible sonames). The sanitizer libraries do not depend on libcrypt, so it can happen that during sanitizer library initialization, no real implementation will be found because the crypt, crypt_r functions are not present in the process image (yet). If its interceptors are called nevertheless, this results in a call through a null pointer when the sanitizer library attempts to forward the call to the real implementation.
>
> Many distributions have already switched to libxcrypt, a library that is separate from glibc and that can be build with sanitizers directly (avoiding the need for interceptors). This patch disables building the interceptor for glibc targets.

Let's remove crypt and crypt_r interceptors (D68431) to fix issues with
newer glibc.

For older glibc, msan will not know that an uninstrumented crypt_r call
initializes `data`, so there is a risk for false positives. However, with some
codebase survey, I think crypt_r uses are very few and the call sites typically
have a `memset(&data, 0, sizeof(data));` anyway.

Fix https://github.com/google/sanitizers/issues/1365
Related: https://bugzilla.redhat.com/show_bug.cgi?id=2169432

Reviewed By: #sanitizers, fweimer, thesamesam, vitalybuka

Differential Revision: https://reviews.llvm.org/D149403
---
 .../sanitizer_common_interceptors.inc         | 37 -------------------
 .../sanitizer_platform_interceptors.h         |  2 -
 .../sanitizer_platform_limits_posix.cpp       |  8 ----
 .../sanitizer_platform_limits_posix.h         |  1 -
 .../TestCases/Linux/crypt_r.cpp               | 36 ------------------
 .../TestCases/Posix/crypt.cpp                 | 32 ----------------
 6 files changed, 116 deletions(-)
 delete mode 100644 compiler-rt/test/sanitizer_common/TestCases/Linux/crypt_r.cpp
 delete mode 100644 compiler-rt/test/sanitizer_common/TestCases/Posix/crypt.cpp

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index b30c91f06cfeb0..490a8b12d8b17d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -10086,41 +10086,6 @@ INTERCEPTOR(SSIZE_T, getrandom, void *buf, SIZE_T buflen, unsigned int flags) {
 #define INIT_GETRANDOM
 #endif
 
-#if SANITIZER_INTERCEPT_CRYPT
-INTERCEPTOR(char *, crypt, char *key, char *salt) {
-  void *ctx;
-  COMMON_INTERCEPTOR_ENTER(ctx, crypt, key, salt);
-  COMMON_INTERCEPTOR_READ_RANGE(ctx, key, internal_strlen(key) + 1);
-  COMMON_INTERCEPTOR_READ_RANGE(ctx, salt, internal_strlen(salt) + 1);
-  char *res = REAL(crypt)(key, salt);
-  if (res != nullptr)
-    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, internal_strlen(res) + 1);
-  return res;
-}
-#define INIT_CRYPT COMMON_INTERCEPT_FUNCTION(crypt);
-#else
-#define INIT_CRYPT
-#endif
-
-#if SANITIZER_INTERCEPT_CRYPT_R
-INTERCEPTOR(char *, crypt_r, char *key, char *salt, void *data) {
-  void *ctx;
-  COMMON_INTERCEPTOR_ENTER(ctx, crypt_r, key, salt, data);
-  COMMON_INTERCEPTOR_READ_RANGE(ctx, key, internal_strlen(key) + 1);
-  COMMON_INTERCEPTOR_READ_RANGE(ctx, salt, internal_strlen(salt) + 1);
-  char *res = REAL(crypt_r)(key, salt, data);
-  if (res != nullptr) {
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, data,
-                                   __sanitizer::struct_crypt_data_sz);
-    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, internal_strlen(res) + 1);
-  }
-  return res;
-}
-#define INIT_CRYPT_R COMMON_INTERCEPT_FUNCTION(crypt_r);
-#else
-#define INIT_CRYPT_R
-#endif
-
 #if SANITIZER_INTERCEPT_GETENTROPY
 INTERCEPTOR(int, getentropy, void *buf, SIZE_T buflen) {
   void *ctx;
@@ -10698,8 +10663,6 @@ static void InitializeCommonInterceptors() {
   INIT_GETUSERSHELL;
   INIT_SL_INIT;
   INIT_GETRANDOM;
-  INIT_CRYPT;
-  INIT_CRYPT_R;
   INIT_GETENTROPY;
   INIT_QSORT;
   INIT_QSORT_R;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
index eb39fabfd59839..c82ab5c2105621 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -569,8 +569,6 @@
 #define SANITIZER_INTERCEPT_FDEVNAME SI_FREEBSD
 #define SANITIZER_INTERCEPT_GETUSERSHELL (SI_POSIX && !SI_ANDROID)
 #define SANITIZER_INTERCEPT_SL_INIT (SI_FREEBSD || SI_NETBSD)
-#define SANITIZER_INTERCEPT_CRYPT (SI_POSIX && !SI_ANDROID)
-#define SANITIZER_INTERCEPT_CRYPT_R (SI_LINUX && !SI_ANDROID)
 
 #define SANITIZER_INTERCEPT_GETRANDOM \
   ((SI_LINUX && __GLIBC_PREREQ(2, 25)) || SI_FREEBSD)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
index a04eed7aa5a6e..6d61d276d77e3 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp
@@ -142,5 +142,4 @@
 #include <linux/serial.h>
 #include <sys/msg.h>
 #include <sys/ipc.h>
-#include <crypt.h>
 #endif  // SANITIZER_ANDROID
@@ -243,7 +244,6 @@
   unsigned struct_ustat_sz = SIZEOF_STRUCT_USTAT;
   unsigned struct_rlimit64_sz = sizeof(struct rlimit64);
   unsigned struct_statvfs64_sz = sizeof(struct statvfs64);
-  unsigned struct_crypt_data_sz = sizeof(struct crypt_data);
 #endif // SANITIZER_LINUX && !SANITIZER_ANDROID
 
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
index e6f298c26e1fb6..58244c9944a03a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -309,7 +309,6 @@ extern unsigned struct_msqid_ds_sz;
 extern unsigned struct_mq_attr_sz;
 extern unsigned struct_timex_sz;
 extern unsigned struct_statvfs_sz;
-extern unsigned struct_crypt_data_sz;
 #endif  // SANITIZER_LINUX && !SANITIZER_ANDROID
 
 struct __sanitizer_iovec {
diff --git a/compiler-rt/test/sanitizer_common/TestCases/Linux/crypt_r.cpp b/compiler-rt/test/sanitizer_common/TestCases/Linux/crypt_r.cpp
deleted file mode 100644
index 69bfb46aa5f171..00000000000000
--- a/compiler-rt/test/sanitizer_common/TestCases/Linux/crypt_r.cpp
+++ /dev/null
@@ -1,36 +0,0 @@
-// RUN: %clangxx -O0 -g %s -lcrypt -o %t && %run %t
-
-// crypt.h is missing from Android.
-// UNSUPPORTED: android
-
-#include <assert.h>
-#include <unistd.h>
-#include <cstring>
-#include <crypt.h>
-
-int main(int argc, char **argv) {
-  {
-    crypt_data cd;
-    cd.initialized = 0;
-    char *p = crypt_r("abcdef", "xz", &cd);
-    volatile size_t z = strlen(p);
-  }
-  {
-    crypt_data cd;
-    cd.initialized = 0;
-    char *p = crypt_r("abcdef", "$1$", &cd);
-    volatile size_t z = strlen(p);
-  }
-  {
-    crypt_data cd;
-    cd.initialized = 0;
-    char *p = crypt_r("abcdef", "$5$", &cd);
-    volatile size_t z = strlen(p);
-  }
-  {
-    crypt_data cd;
-    cd.initialized = 0;
-    char *p = crypt_r("abcdef", "$6$", &cd);
-    volatile size_t z = strlen(p);
-  }
-}
diff --git a/compiler-rt/test/sanitizer_common/TestCases/Posix/crypt.cpp b/compiler-rt/test/sanitizer_common/TestCases/Posix/crypt.cpp
deleted file mode 100644
index 3a8faaa1ae7682..00000000000000
--- a/compiler-rt/test/sanitizer_common/TestCases/Posix/crypt.cpp
+++ /dev/null
@@ -1,32 +0,0 @@
-// RUN: %clangxx -O0 -g %s -o %t -lcrypt && %run %t
-
-// crypt() is missing from Android and -lcrypt from darwin.
-// UNSUPPORTED: android, darwin
-
-#include <assert.h>
-#include <unistd.h>
-#include <cstring>
-#if __has_include(<crypt.h>)
-#include <crypt.h>
-#endif
-
-int
-main (int argc, char** argv)
-{
-  {
-    char *p = crypt("abcdef", "xz");
-    volatile size_t z = strlen(p);
-  }
-  {
-    char *p = crypt("abcdef", "$1$");
-    volatile size_t z = strlen(p);
-  }
-  {
-    char *p = crypt("abcdef", "$5$");
-    volatile size_t z = strlen(p);
-  }
-  {
-    char *p = crypt("abcdef", "$6$");
-    volatile size_t z = strlen(p);
-  }
-}
