From bf61483b6a5e32cb397f97a1cd4af2a41d46ade3 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Fri, 28 Apr 2023 09:59:17 -0700 Subject: [PATCH] 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 | 2 - .../sanitizer_platform_limits_posix.h | 1 - 4 files changed, 42 deletions(-) diff --git a/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc b/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc index abb38ccfa15d..61250226aa56 100644 --- a/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc +++ b/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc @@ -9977,41 +9977,6 @@ 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; @@ -10521,8 +10486,6 @@ 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/libsanitizer/sanitizer_common/sanitizer_platform_interceptors.h b/libsanitizer/sanitizer_common/sanitizer_platform_interceptors.h index 14610f2df78d..787db66ae2b7 100644 --- a/libsanitizer/sanitizer_common/sanitizer_platform_interceptors.h +++ b/libsanitizer/sanitizer_common/sanitizer_platform_interceptors.h @@ -568,8 +568,6 @@ #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/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cpp b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cpp index c335f33dda58..bfdccd5df078 100644 --- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cpp +++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cpp @@ -154,7 +154,6 @@ typedef struct user_fpregs elf_fpregset_t; #include #include #include -#include #endif // SANITIZER_ANDROID #include @@ -254,7 +253,6 @@ namespace __sanitizer { 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/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h index da53b5abef27..2605bb849a78 100644 --- a/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h +++ b/libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.h @@ -298,7 +298,6 @@ 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 { -- 2.43.0