diff options
| author | Theo de Raadt <deraadt@cvs.openbsd.org> | 2017-07-30 21:40:15 +0000 |
|---|---|---|
| committer | Theo de Raadt <deraadt@cvs.openbsd.org> | 2017-07-30 21:40:15 +0000 |
| commit | d914126a37c567ba9e58a531100f88688e202d68 (patch) | |
| tree | 97cb10238bd1bdb325b53f4a4a4566c08c71e9fe /sys/dev | |
| parent | d4bd8662437bf8562416b788731906c1b700a1dd (diff) | |
clang (and newer gcc at high -O) are unaware that objects placed in strange
sections, such as __attribute__((section(".openbsd.randomdata"))), may be
non-zero. In combination with "const" or "static" the compiler becomes even
more sure nothing can influence the object and assumes the value will be 0.
A few optimizations later, a security requirement has been removed.
Until a better annotation arrives in compilers, be warned: Do not mix
const or static with these random objects, you won't get what you want.
Spotted in a regression test by bluhm, long discussion with kettenis.
Diffstat (limited to 'sys/dev')
| -rw-r--r-- | sys/dev/rnd.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/sys/dev/rnd.c b/sys/dev/rnd.c index 0fe29bdea1c..cec2e1a2292 100644 --- a/sys/dev/rnd.c +++ b/sys/dev/rnd.c @@ -1,4 +1,4 @@ -/* $OpenBSD: rnd.c,v 1.192 2017/03/15 15:24:24 deraadt Exp $ */ +/* $OpenBSD: rnd.c,v 1.193 2017/07/30 21:40:14 deraadt Exp $ */ /* * Copyright (c) 2011 Theo de Raadt. @@ -225,7 +225,7 @@ u_int rnd_event_idx; struct timeout rnd_timeout; static u_int32_t entropy_pool[POOLWORDS]; -static const u_int32_t entropy_pool0[POOLWORDS] __attribute__((section(".openbsd.randomdata"))); +u_int32_t entropy_pool0[POOLWORDS] __attribute__((section(".openbsd.randomdata"))); u_int entropy_add_ptr; u_char entropy_input_rotate; @@ -442,7 +442,7 @@ struct task arc4_task = TASK_INITIALIZER(arc4_init, NULL); static chacha_ctx rs; /* chacha context for random keystream */ /* keystream blocks (also chacha seed from boot) */ static u_char rs_buf[RSBUFSZ]; -static const u_char rs_buf0[RSBUFSZ] __attribute__((section(".openbsd.randomdata"))); +u_char rs_buf0[RSBUFSZ] __attribute__((section(".openbsd.randomdata"))); static size_t rs_have; /* valid bytes at end of rs_buf */ static size_t rs_count; /* bytes till reseed */ |