From 4e496f3dc65a965f763b1d650e9bcbb039df32bc Mon Sep 17 00:00:00 2001 From: mortimer Date: Fri, 9 Feb 2018 22:13:04 +0000 Subject: [PATCH] Use a static chacha instance to fill randomdata sections. Avoids looping over a syscall for randomdata sections larger than 256B. ok djm@ deraadt@ kettenis@ --- libexec/ld.so/chacha_private.h | 222 +++++++++++++++++++++++++++++++++ libexec/ld.so/util.c | 58 ++++----- 2 files changed, 247 insertions(+), 33 deletions(-) create mode 100644 libexec/ld.so/chacha_private.h diff --git a/libexec/ld.so/chacha_private.h b/libexec/ld.so/chacha_private.h new file mode 100644 index 00000000000..222efdff67a --- /dev/null +++ b/libexec/ld.so/chacha_private.h @@ -0,0 +1,222 @@ +/* +chacha-merged.c version 20080118 +D. J. Bernstein +Public domain. +*/ + +/* $OpenBSD: chacha_private.h,v 1.1 2018/02/09 22:13:04 mortimer Exp $ */ + +typedef unsigned char u8; +typedef unsigned int u32; + +typedef struct +{ + u32 input[16]; /* could be compressed */ +} chacha_ctx; + +#define U8C(v) (v##U) +#define U32C(v) (v##U) + +#define U8V(v) ((u8)(v) & U8C(0xFF)) +#define U32V(v) ((u32)(v) & U32C(0xFFFFFFFF)) + +#define ROTL32(v, n) \ + (U32V((v) << (n)) | ((v) >> (32 - (n)))) + +#define U8TO32_LITTLE(p) \ + (((u32)((p)[0]) ) | \ + ((u32)((p)[1]) << 8) | \ + ((u32)((p)[2]) << 16) | \ + ((u32)((p)[3]) << 24)) + +#define U32TO8_LITTLE(p, v) \ + do { \ + (p)[0] = U8V((v) ); \ + (p)[1] = U8V((v) >> 8); \ + (p)[2] = U8V((v) >> 16); \ + (p)[3] = U8V((v) >> 24); \ + } while (0) + +#define ROTATE(v,c) (ROTL32(v,c)) +#define XOR(v,w) ((v) ^ (w)) +#define PLUS(v,w) (U32V((v) + (w))) +#define PLUSONE(v) (PLUS((v),1)) + +#define QUARTERROUND(a,b,c,d) \ + a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \ + a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c), 7); + +static const char sigma[16] = "expand 32-byte k"; +static const char tau[16] = "expand 16-byte k"; + +static void +chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits) +{ + const char *constants; + + x->input[4] = U8TO32_LITTLE(k + 0); + x->input[5] = U8TO32_LITTLE(k + 4); + x->input[6] = U8TO32_LITTLE(k + 8); + x->input[7] = U8TO32_LITTLE(k + 12); + if (kbits == 256) { /* recommended */ + k += 16; + constants = sigma; + } else { /* kbits == 128 */ + constants = tau; + } + x->input[8] = U8TO32_LITTLE(k + 0); + x->input[9] = U8TO32_LITTLE(k + 4); + x->input[10] = U8TO32_LITTLE(k + 8); + x->input[11] = U8TO32_LITTLE(k + 12); + x->input[0] = U8TO32_LITTLE(constants + 0); + x->input[1] = U8TO32_LITTLE(constants + 4); + x->input[2] = U8TO32_LITTLE(constants + 8); + x->input[3] = U8TO32_LITTLE(constants + 12); +} + +static void +chacha_ivsetup(chacha_ctx *x,const u8 *iv) +{ + x->input[12] = 0; + x->input[13] = 0; + x->input[14] = U8TO32_LITTLE(iv + 0); + x->input[15] = U8TO32_LITTLE(iv + 4); +} + +static void +chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes) +{ + u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; + u32 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; + u8 *ctarget = NULL; + u8 tmp[64]; + u_int i; + + if (!bytes) return; + + j0 = x->input[0]; + j1 = x->input[1]; + j2 = x->input[2]; + j3 = x->input[3]; + j4 = x->input[4]; + j5 = x->input[5]; + j6 = x->input[6]; + j7 = x->input[7]; + j8 = x->input[8]; + j9 = x->input[9]; + j10 = x->input[10]; + j11 = x->input[11]; + j12 = x->input[12]; + j13 = x->input[13]; + j14 = x->input[14]; + j15 = x->input[15]; + + for (;;) { + if (bytes < 64) { + for (i = 0;i < bytes;++i) tmp[i] = m[i]; + m = tmp; + ctarget = c; + c = tmp; + } + x0 = j0; + x1 = j1; + x2 = j2; + x3 = j3; + x4 = j4; + x5 = j5; + x6 = j6; + x7 = j7; + x8 = j8; + x9 = j9; + x10 = j10; + x11 = j11; + x12 = j12; + x13 = j13; + x14 = j14; + x15 = j15; + for (i = 20;i > 0;i -= 2) { + QUARTERROUND( x0, x4, x8,x12) + QUARTERROUND( x1, x5, x9,x13) + QUARTERROUND( x2, x6,x10,x14) + QUARTERROUND( x3, x7,x11,x15) + QUARTERROUND( x0, x5,x10,x15) + QUARTERROUND( x1, x6,x11,x12) + QUARTERROUND( x2, x7, x8,x13) + QUARTERROUND( x3, x4, x9,x14) + } + x0 = PLUS(x0,j0); + x1 = PLUS(x1,j1); + x2 = PLUS(x2,j2); + x3 = PLUS(x3,j3); + x4 = PLUS(x4,j4); + x5 = PLUS(x5,j5); + x6 = PLUS(x6,j6); + x7 = PLUS(x7,j7); + x8 = PLUS(x8,j8); + x9 = PLUS(x9,j9); + x10 = PLUS(x10,j10); + x11 = PLUS(x11,j11); + x12 = PLUS(x12,j12); + x13 = PLUS(x13,j13); + x14 = PLUS(x14,j14); + x15 = PLUS(x15,j15); + +#ifndef KEYSTREAM_ONLY + x0 = XOR(x0,U8TO32_LITTLE(m + 0)); + x1 = XOR(x1,U8TO32_LITTLE(m + 4)); + x2 = XOR(x2,U8TO32_LITTLE(m + 8)); + x3 = XOR(x3,U8TO32_LITTLE(m + 12)); + x4 = XOR(x4,U8TO32_LITTLE(m + 16)); + x5 = XOR(x5,U8TO32_LITTLE(m + 20)); + x6 = XOR(x6,U8TO32_LITTLE(m + 24)); + x7 = XOR(x7,U8TO32_LITTLE(m + 28)); + x8 = XOR(x8,U8TO32_LITTLE(m + 32)); + x9 = XOR(x9,U8TO32_LITTLE(m + 36)); + x10 = XOR(x10,U8TO32_LITTLE(m + 40)); + x11 = XOR(x11,U8TO32_LITTLE(m + 44)); + x12 = XOR(x12,U8TO32_LITTLE(m + 48)); + x13 = XOR(x13,U8TO32_LITTLE(m + 52)); + x14 = XOR(x14,U8TO32_LITTLE(m + 56)); + x15 = XOR(x15,U8TO32_LITTLE(m + 60)); +#endif + + j12 = PLUSONE(j12); + if (!j12) { + j13 = PLUSONE(j13); + /* stopping at 2^70 bytes per nonce is user's responsibility */ + } + + U32TO8_LITTLE(c + 0,x0); + U32TO8_LITTLE(c + 4,x1); + U32TO8_LITTLE(c + 8,x2); + U32TO8_LITTLE(c + 12,x3); + U32TO8_LITTLE(c + 16,x4); + U32TO8_LITTLE(c + 20,x5); + U32TO8_LITTLE(c + 24,x6); + U32TO8_LITTLE(c + 28,x7); + U32TO8_LITTLE(c + 32,x8); + U32TO8_LITTLE(c + 36,x9); + U32TO8_LITTLE(c + 40,x10); + U32TO8_LITTLE(c + 44,x11); + U32TO8_LITTLE(c + 48,x12); + U32TO8_LITTLE(c + 52,x13); + U32TO8_LITTLE(c + 56,x14); + U32TO8_LITTLE(c + 60,x15); + + if (bytes <= 64) { + if (bytes < 64) { + for (i = 0;i < bytes;++i) ctarget[i] = c[i]; + } + x->input[12] = j12; + x->input[13] = j13; + return; + } + bytes -= 64; + c += 64; +#ifndef KEYSTREAM_ONLY + m += 64; +#endif + } +} diff --git a/libexec/ld.so/util.c b/libexec/ld.so/util.c index 7910b09248f..d6d762df48b 100644 --- a/libexec/ld.so/util.c +++ b/libexec/ld.so/util.c @@ -1,4 +1,4 @@ -/* $OpenBSD: util.c,v 1.44 2017/01/24 07:48:37 guenther Exp $ */ +/* $OpenBSD: util.c,v 1.45 2018/02/09 22:13:04 mortimer Exp $ */ /* * Copyright (c) 1998 Per Fogelstrom, Opsycon AB @@ -30,6 +30,8 @@ #include #include "archdep.h" #include "resolve.h" +#define KEYSTREAM_ONLY +#include "chacha_private.h" /* * Stack protector dummies. @@ -40,6 +42,12 @@ long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata"))); void __stack_smash_handler(char [], int); +#define KEYSZ 32 +#define IVSZ 8 +#define REKEY_AFTER_BYTES (1 << 31) +static chacha_ctx chacha; +static size_t chacha_bytes; + void __stack_smash_handler(char func[], int damaged) { @@ -72,41 +80,25 @@ _dl_strdup(const char *orig) } void -_dl_arc4randombuf(void *v, size_t buflen) +_dl_arc4randombuf(void *buf, size_t buflen) { - static char bytes[256]; - static u_int reserve; - char *buf = v; - size_t chunk; + if (chacha_bytes == 0) { + char bytes[KEYSZ + IVSZ]; - while (buflen != 0) { - if (reserve == 0) { - if (_dl_getentropy(bytes, sizeof(bytes)) != 0) - _dl_die("no entropy"); - reserve = sizeof(bytes); - } - if (buflen > reserve) - chunk = reserve; - else - chunk = buflen; -#if 0 - memcpy(buf, bytes + reserve - chunk, chunk); - memset(bytes + reserve - chunk, 0, chunk); -#else - { - char *d = buf; - char *s = bytes + reserve - chunk; - u_int l; - for (l = chunk; l > 0; l--, s++, d++) { - *d = *s; - *s = 0; - } - } -#endif - reserve -= chunk; - buflen -= chunk; - buf += chunk; + if (_dl_getentropy(bytes, KEYSZ + IVSZ) != 0) + _dl_die("no entropy"); + chacha_keysetup(&chacha, bytes, KEYSZ * 8); + chacha_ivsetup(&chacha, bytes + KEYSZ); + if (_dl_getentropy(bytes, KEYSZ + IVSZ) != 0) + _dl_die("could not clobber rng key"); } + + chacha_encrypt_bytes(&chacha, buf, buf, buflen); + + if (REKEY_AFTER_BYTES - chacha_bytes < buflen) + chacha_bytes = 0; + else + chacha_bytes += buflen; } u_int32_t -- 2.20.1