diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake index fa561d1a..001dfd68 100644 --- a/ConfigureChecks.cmake +++ b/ConfigureChecks.cmake @@ -181,6 +181,18 @@ int main(void) { return 0; }" HAVE_MSC_THREAD_LOCAL_STORAGE) +check_c_source_compiles(" +#include + +int main(void) +{ + char buf[] = \"This is some content\"; + + memset(buf, '\\\\0', sizeof(buf)); __asm__ volatile(\"\" : : \"r\"(&buf) : \"memory\"); + + return 0; +}" HAVE_GCC_VOLATILE_MEMORY_PROTECTION) + if (WITH_DEBUG_CRYPTO) set(DEBUG_CRYPTO 1) endif (WITH_DEBUG_CRYPTO) diff --git a/config.h.cmake b/config.h.cmake index 16c60529..18d82e4b 100644 --- a/config.h.cmake +++ b/config.h.cmake @@ -126,6 +126,8 @@ #cmakedefine HAVE_GCC_THREAD_LOCAL_STORAGE 1 #cmakedefine HAVE_MSC_THREAD_LOCAL_STORAGE 1 +#cmakedefine HAVE_GCC_VOLATILE_MEMORY_PROTECTION 1 + /* Define to 1 if you want to enable GSSAPI */ #cmakedefine WITH_GSSAPI 1 diff --git a/include/libssh/priv.h b/include/libssh/priv.h index abf307ad..44806ab6 100644 --- a/include/libssh/priv.h +++ b/include/libssh/priv.h @@ -137,6 +137,17 @@ int gettimeofday(struct timeval *__p, void *__t); # define LIBSSH_THREAD #endif +/* + * This makes sure that the compiler doesn't optimize out the code + * + * Use it in a macro where the provided variable is 'x'. + */ +#if defined(HAVE_GCC_VOLATILE_MEMORY_PROTECTION) +# define LIBSSH_MEM_PROTECTION __asm__ volatile("" : : "r"(&(x)) : "memory") +#else +# define LIBSSH_MEM_PROTECTION +#endif + #ifdef HAVE_SYS_TIME_H #include #endif @@ -226,11 +237,33 @@ int match_hostname(const char *host, const char *pattern, unsigned int len); /** Get the size of an array */ #define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0])) +/* + * See http://llvm.org/bugs/show_bug.cgi?id=15495 + */ +#if defined(HAVE_GCC_VOLATILE_MEMORY_PROTECTION) /** Overwrite a string with '\0' */ -#define BURN_STRING(x) do { if ((x) != NULL) memset((x), '\0', strlen((x))); __asm__ volatile ("" : : : "memory"); } while(0) +# define BURN_STRING(x) do { \ + if ((x) != NULL) \ + memset((x), '\0', strlen((x))); __asm__ volatile("" : : "r"(&(x)) : "memory"); \ + } while(0) /** Overwrite the buffer with '\0' */ -#define BURN_BUFFER(x, size) do { if ((x) != NULL) memset((x), '\0', (size))); __asm__ volatile ("") : : : "memory"; } while(0) +# define BURN_BUFFER(x, size) do { \ + if ((x) != NULL) \ + memset((x), '\0', (size))); __asm__ volatile("" : : "r"(&(x)) : "memory"); \ + } while(0) +#else /* HAVE_GCC_VOLATILE_MEMORY_PROTECTION */ +/** Overwrite a string with '\0' */ +# define BURN_STRING(x) do { \ + if ((x) != NULL) memset((x), '\0', strlen((x))); \ + } while(0) + +/** Overwrite the buffer with '\0' */ +# define BURN_BUFFER(x, size) do { \ + if ((x) != NULL) \ + memset((x), '\0', (size))); __asm__ volatile("" : : "r"(&(x)) : "memory"); \ + } while(0) +#endif /* HAVE_GCC_VOLATILE_MEMORY_PROTECTION */ /** * This is a hack to fix warnings. The idea is to use this everywhere that we