From 246bd926488b15fcf9867c2a9372a8c173567ffe Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C5=99emysl=20Janouch?= Date: Tue, 14 Jul 2015 23:39:40 +0200 Subject: [PATCH] Allow str_map siphash key randomization --- liberty.c | 117 +++++++++++++++++++++++++++++++++++------------------- 1 file changed, 76 insertions(+), 41 deletions(-) diff --git a/liberty.c b/liberty.c index ad1efba..41e4c6e 100644 --- a/liberty.c +++ b/liberty.c @@ -659,6 +659,80 @@ error_propagate (struct error **destination, struct error *source) *destination = source; } +// --- File descriptor utilities ----------------------------------------------- + +static void +set_cloexec (int fd) +{ + soft_assert (fcntl (fd, F_SETFD, fcntl (fd, F_GETFD) | FD_CLOEXEC) != -1); +} + +static bool +set_blocking (int fd, bool blocking) +{ + int flags = fcntl (fd, F_GETFL); + hard_assert (flags != -1); + + bool prev = !(flags & O_NONBLOCK); + if (blocking) + flags &= ~O_NONBLOCK; + else + flags |= O_NONBLOCK; + + hard_assert (fcntl (fd, F_SETFL, flags) != -1); + return prev; +} + +static void +xclose (int fd) +{ + while (close (fd) == -1) + if (!soft_assert (errno == EINTR)) + break; +} + +// --- Randomness -------------------------------------------------------------- + +static bool +random_bytes (void *output, size_t len, struct error **e) +{ + bool result = false; + int fd = open ("/dev/urandom", O_RDONLY); + ssize_t got = 0; + + if (fd < 0) + { + error_set (e, "%s: %s", "open", strerror (errno)); + return false; + } + else if ((got = read (fd, output, len)) < 0) + error_set (e, "%s: %s", "read", strerror (errno)); + else if (got != (ssize_t) len) + error_set (e, "can't get enough bytes from the device"); + else + result = true; + + xclose (fd); + return result; +} + +// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + +static unsigned char g_siphash_key[16] = "SipHash 2-4 key!"; + +static inline void +siphash_wrapper_randomize (void) +{ + // I guess there's no real need to be this paranoic, so we ignore failures + soft_assert (random_bytes (g_siphash_key, sizeof g_siphash_key, NULL)); +} + +static inline uint64_t +siphash_wrapper (const void *m, size_t len) +{ + return siphash (g_siphash_key, m, len); +} + // --- String hash map --------------------------------------------------------- // The most basic map (or associative array). @@ -728,24 +802,17 @@ str_map_free (struct str_map *self) self->map = NULL; } -static uint64_t -str_map_hash (const char *s, size_t len) -{ - static unsigned char key[16] = "SipHash 2-4 key!"; - return siphash (key, (const void *) s, len); -} - static uint64_t str_map_pos (struct str_map *self, const char *s) { size_t mask = self->alloc - 1; - return str_map_hash (s, strlen (s)) & mask; + return siphash_wrapper (s, strlen (s)) & mask; } static uint64_t str_map_link_hash (struct str_map_link *self) { - return str_map_hash (self->key, self->key_length); + return siphash_wrapper (self->key, self->key_length); } static void @@ -959,38 +1026,6 @@ str_map_unset_iter_free (struct str_map_unset_iter *self) str_map_shrink (self->iter.map); } -// --- File descriptor utilities ----------------------------------------------- - -static void -set_cloexec (int fd) -{ - soft_assert (fcntl (fd, F_SETFD, fcntl (fd, F_GETFD) | FD_CLOEXEC) != -1); -} - -static bool -set_blocking (int fd, bool blocking) -{ - int flags = fcntl (fd, F_GETFL); - hard_assert (flags != -1); - - bool prev = !(flags & O_NONBLOCK); - if (blocking) - flags &= ~O_NONBLOCK; - else - flags |= O_NONBLOCK; - - hard_assert (fcntl (fd, F_SETFL, flags) != -1); - return prev; -} - -static void -xclose (int fd) -{ - while (close (fd) == -1) - if (!soft_assert (errno == EINTR)) - break; -} - // --- Event loop -------------------------------------------------------------- #ifdef LIBERTY_WANT_POLLER