diff options
Diffstat (limited to 'freebsd/contrib/wpa/src/utils/common.c')
| -rw-r--r-- | freebsd/contrib/wpa/src/utils/common.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/freebsd/contrib/wpa/src/utils/common.c b/freebsd/contrib/wpa/src/utils/common.c index a1fdfae7..0eb8bc66 100644 --- a/freebsd/contrib/wpa/src/utils/common.c +++ b/freebsd/contrib/wpa/src/utils/common.c @@ -232,6 +232,16 @@ void inc_byte_array(u8 *counter, size_t len) } +void buf_shift_right(u8 *buf, size_t len, size_t bits) +{ + size_t i; + + for (i = len - 1; i > 0; i--) + buf[i] = (buf[i - 1] << (8 - bits)) | (buf[i] >> bits); + buf[0] >>= bits; +} + + void wpa_get_ntp_timestamp(u8 *buf) { struct os_time now; @@ -962,7 +972,7 @@ void str_clear_free(char *str) { if (str) { size_t len = os_strlen(str); - os_memset(str, 0, len); + forced_memzero(str, len); os_free(str); } } @@ -971,7 +981,7 @@ void str_clear_free(char *str) void bin_clear_free(void *bin, size_t len) { if (bin) { - os_memset(bin, 0, len); + forced_memzero(bin, len); os_free(bin); } } @@ -1251,3 +1261,22 @@ char * get_param(const char *cmd, const char *param) val[len] = '\0'; return val; } + + +/* Try to prevent most compilers from optimizing out clearing of memory that + * becomes unaccessible after this function is called. This is mostly the case + * for clearing local stack variables at the end of a function. This is not + * exactly perfect, i.e., someone could come up with a compiler that figures out + * the pointer is pointing to memset and then end up optimizing the call out, so + * try go a bit further by storing the first octet (now zero) to make this even + * a bit more difficult to optimize out. Once memset_s() is available, that + * could be used here instead. */ +static void * (* const volatile memset_func)(void *, int, size_t) = memset; +static u8 forced_memzero_val; + +void forced_memzero(void *ptr, size_t len) +{ + memset_func(ptr, 0, len); + if (len) + forced_memzero_val = ((u8 *) ptr)[0]; +} |