From patchwork Tue Dec 10 03:49:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sam James X-Patchwork-Id: 2020441 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Y6lC90S8Gz1yR6 for ; Tue, 10 Dec 2024 14:51:16 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 23137385843F for ; Tue, 10 Dec 2024 03:51:15 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 23137385843F X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) by sourceware.org (Postfix) with ESMTP id C935D3858D33 for ; Tue, 10 Dec 2024 03:50:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org C935D3858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gentoo.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gentoo.org ARC-Filter: OpenARC Filter v1.0.0 sourceware.org C935D3858D33 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=140.211.166.183 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1733802645; cv=none; b=YQ574dT/tRNxZI6y7sdRlXHMX432U7IyL0f55SaoDDQ/JClNkciLtKetdYbIz4Xl5/tW7f2/hJayp1bbJapGF/+Du58nTNCqxnxcRaZEi6T2nxrJxUaVwBZLAIV7Bvts6LNYBSK7Ekta4+mucNYz+6nREw9QepvTGXqhhjgWF78= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1733802645; c=relaxed/simple; bh=leAE/UfRFhn8EtW/mg8HbQI413a1308ITXnGcwtx/5w=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=MbBaUH81uYhqcjGbCEEzlMyJ6bmohZlm2dZSsIuf19pJSQIzlCKzHAeVRT9TEhLUUuyQkJ+Oaxi5vaiz5mZyua16zPPeLczYXKoUDMp+dxnUeEbP+6s2qcKj27UfcVUIV+uCspSxCKsZRcWJm5CgQnyFoo5C8palTNsVW8Bi+KE= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C935D3858D33 From: Sam James To: libc-alpha@sourceware.org Cc: Sam James , Adhemerval Zanella Subject: [PATCH] stdlib: random_r: fix unaligned access in initstate and initstate_r [BZ #30584] Date: Tue, 10 Dec 2024 03:49:52 +0000 Message-ID: <6180a8251d3f8d714ff13d27ccce48e44845661b.1733802592.git.sam@gentoo.org> X-Mailer: git-send-email 2.47.1 MIME-Version: 1.0 X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org The initstate{,_r} interfaces are documented in BSD as needing an aligned array of 32-bit values, but neither POSIX nor glibc's own documentation require it to be aligned. glibc's documentation says it "should" be a power of 2, but not must. Use memcpy to read and write to `state` to handle such an unaligned argument. Co-authored-by: Adhemerval Zanella --- Tested on x86_64-pc-linux-gnu and sparc64-unknown-linux-gnu. stdlib/Makefile | 1 + stdlib/random_r.c | 39 ++++++++++++++++++++++++++----------- stdlib/tst-random-bz30584.c | 39 +++++++++++++++++++++++++++++++++++++ 3 files changed, 68 insertions(+), 11 deletions(-) create mode 100644 stdlib/tst-random-bz30584.c diff --git a/stdlib/Makefile b/stdlib/Makefile index 370cfa57aa..715446970f 100644 --- a/stdlib/Makefile +++ b/stdlib/Makefile @@ -299,6 +299,7 @@ tests := \ tst-rand48-2 \ tst-random \ tst-random2 \ + tst-random-bz30584 \ tst-realpath \ tst-realpath-toolong \ tst-secure-getenv \ diff --git a/stdlib/random_r.c b/stdlib/random_r.c index b6297fe099..dee3bc9535 100644 --- a/stdlib/random_r.c +++ b/stdlib/random_r.c @@ -55,6 +55,7 @@ #include #include #include +#include /* An improved random number generation package. In addition to the standard @@ -146,7 +147,19 @@ static const struct random_poly_info random_poly_info = { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 } }; +static inline int32_t +read_state (int32_t *b, size_t idx) +{ + int32_t r; + memcpy (&r, &b[idx], sizeof (int32_t)); + return r; +} +static inline void +write_state (int32_t *b, size_t idx, int32_t v) +{ + memcpy (&b[idx], &v, sizeof (int32_t)); +} /* Initialize the random number generator based on the given seed. If the @@ -177,7 +190,7 @@ __srandom_r (unsigned int seed, struct random_data *buf) /* We must make sure the seed is not 0. Take arbitrarily 1 in this case. */ if (seed == 0) seed = 1; - state[0] = seed; + write_state (state, 0, seed); if (type == TYPE_0) goto done; @@ -194,7 +207,7 @@ __srandom_r (unsigned int seed, struct random_data *buf) word = 16807 * lo - 2836 * hi; if (word < 0) word += 2147483647; - *++dst = word; + write_state (++dst, 0, word); } buf->fptr = &state[buf->rand_sep]; @@ -238,9 +251,10 @@ __initstate_r (unsigned int seed, char *arg_state, size_t n, { int old_type = buf->rand_type; if (old_type == TYPE_0) - old_state[-1] = TYPE_0; + write_state (old_state, -1, TYPE_0); else - old_state[-1] = (MAX_TYPES * (buf->rptr - old_state)) + old_type; + write_state (old_state, -1, (MAX_TYPES * (buf->rptr - old_state)) + + old_type); } int type; @@ -270,9 +284,9 @@ __initstate_r (unsigned int seed, char *arg_state, size_t n, __srandom_r (seed, buf); - state[-1] = TYPE_0; + write_state (state, -1, TYPE_0); if (type != TYPE_0) - state[-1] = (buf->rptr - state) * MAX_TYPES + type; + write_state (state, -1, (buf->rptr - state) * MAX_TYPES + type); return 0; @@ -307,9 +321,10 @@ __setstate_r (char *arg_state, struct random_data *buf) old_type = buf->rand_type; old_state = buf->state; if (old_type == TYPE_0) - old_state[-1] = TYPE_0; + write_state (old_state, -1, TYPE_0); else - old_state[-1] = (MAX_TYPES * (buf->rptr - old_state)) + old_type; + write_state (old_state, -1, (MAX_TYPES * (buf->rptr - old_state)) + + old_type); type = new_state[-1] % MAX_TYPES; if (type < TYPE_0 || type > TYPE_4) @@ -361,8 +376,8 @@ __random_r (struct random_data *buf, int32_t *result) if (buf->rand_type == TYPE_0) { - int32_t val = ((state[0] * 1103515245U) + 12345U) & 0x7fffffff; - state[0] = val; + int32_t val = ((read_state(state, 0) * 1103515245U) + 12345U) & 0x7fffffff; + write_state (state, 0, val); *result = val; } else @@ -372,7 +387,9 @@ __random_r (struct random_data *buf, int32_t *result) int32_t *end_ptr = buf->end_ptr; uint32_t val; - val = *fptr += (uint32_t) *rptr; + val = read_state (rptr, 0); + int32_t t = read_state (fptr, 0); + write_state (fptr, 0, t + val); /* Chucking least random bit. */ *result = val >> 1; ++fptr; diff --git a/stdlib/tst-random-bz30584.c b/stdlib/tst-random-bz30584.c new file mode 100644 index 0000000000..2e82dabaf3 --- /dev/null +++ b/stdlib/tst-random-bz30584.c @@ -0,0 +1,39 @@ +/* Test program for initstate(), initstate_r() for BZ #30584. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, see . */ + +#include +#include + +static int +do_test (void) +{ + struct random_data rand_state; + char buf[128 + sizeof (int32_t)]; + rand_state.state = NULL; + + /* Test initstate_r with an unaligned `state` array. */ + initstate_r (time (NULL), buf + 1, sizeof buf - 1, &rand_state); + + /* Ditto initstate. */ + initstate (time (NULL), buf + 1, sizeof buf - 1); + + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c"