diff options
Diffstat (limited to 'compat/arc4random.c')
| -rw-r--r-- | compat/arc4random.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/compat/arc4random.c b/compat/arc4random.c index 2bb4dbf..1ec8e1e 100644 --- a/compat/arc4random.c +++ b/compat/arc4random.c @@ -1,4 +1,4 @@ -/* $OpenBSD: arc4random.c,v 1.55 2019/03/24 17:56:54 deraadt Exp $ */ +/* $OpenBSD: arc4random.c,v 1.58 2022/07/31 13:41:45 tb Exp $ */ /* * Copyright (c) 1996, David Mazieres <dm@uun.org> @@ -49,6 +49,8 @@ #define BLOCKSZ 64 #define RSBUFSZ (16*BLOCKSZ) +#define REKEY_BASE (1024*1024) /* NB. should be a power of 2 */ + /* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */ static struct _rs { size_t rs_have; /* valid bytes at end of rs_buf */ @@ -78,7 +80,7 @@ _rs_init(u_char *buf, size_t n) _exit(1); } - chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8, 0); + chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8); chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ); } @@ -86,6 +88,7 @@ static void _rs_stir(void) { u_char rnd[KEYSZ + IVSZ]; + uint32_t rekey_fuzz = 0; if (getentropy(rnd, sizeof rnd) == -1) _getentropy_fail(); @@ -100,7 +103,10 @@ _rs_stir(void) rs->rs_have = 0; memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf)); - rs->rs_count = 1600000; + /* rekey interval should not be predictable */ + chacha_encrypt_bytes(&rsx->rs_chacha, (uint8_t *)&rekey_fuzz, + (uint8_t *)&rekey_fuzz, sizeof(rekey_fuzz)); + rs->rs_count = REKEY_BASE + (rekey_fuzz % REKEY_BASE); } static inline void |