From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- lib/crypto/memneq.c | 174 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100644 lib/crypto/memneq.c (limited to 'lib/crypto/memneq.c') diff --git a/lib/crypto/memneq.c b/lib/crypto/memneq.c new file mode 100644 index 000000000..08924acd4 --- /dev/null +++ b/lib/crypto/memneq.c @@ -0,0 +1,174 @@ +/* + * Constant-time equality testing of memory regions. + * + * Authors: + * + * James Yonan + * Daniel Borkmann + * + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * GPL LICENSE SUMMARY + * + * Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * The full GNU General Public License is included in this distribution + * in the file called LICENSE.GPL. + * + * BSD LICENSE + * + * Copyright(c) 2013 OpenVPN Technologies, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of OpenVPN Technologies nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include + +/* Generic path for arbitrary size */ +static inline unsigned long +__crypto_memneq_generic(const void *a, const void *b, size_t size) +{ + unsigned long neq = 0; + +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) + while (size >= sizeof(unsigned long)) { + neq |= get_unaligned((unsigned long *)a) ^ + get_unaligned((unsigned long *)b); + OPTIMIZER_HIDE_VAR(neq); + a += sizeof(unsigned long); + b += sizeof(unsigned long); + size -= sizeof(unsigned long); + } +#endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */ + while (size > 0) { + neq |= *(unsigned char *)a ^ *(unsigned char *)b; + OPTIMIZER_HIDE_VAR(neq); + a += 1; + b += 1; + size -= 1; + } + return neq; +} + +/* Loop-free fast-path for frequently used 16-byte size */ +static inline unsigned long __crypto_memneq_16(const void *a, const void *b) +{ + unsigned long neq = 0; + +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + if (sizeof(unsigned long) == 8) { + neq |= get_unaligned((unsigned long *)a) ^ + get_unaligned((unsigned long *)b); + OPTIMIZER_HIDE_VAR(neq); + neq |= get_unaligned((unsigned long *)(a + 8)) ^ + get_unaligned((unsigned long *)(b + 8)); + OPTIMIZER_HIDE_VAR(neq); + } else if (sizeof(unsigned int) == 4) { + neq |= get_unaligned((unsigned int *)a) ^ + get_unaligned((unsigned int *)b); + OPTIMIZER_HIDE_VAR(neq); + neq |= get_unaligned((unsigned int *)(a + 4)) ^ + get_unaligned((unsigned int *)(b + 4)); + OPTIMIZER_HIDE_VAR(neq); + neq |= get_unaligned((unsigned int *)(a + 8)) ^ + get_unaligned((unsigned int *)(b + 8)); + OPTIMIZER_HIDE_VAR(neq); + neq |= get_unaligned((unsigned int *)(a + 12)) ^ + get_unaligned((unsigned int *)(b + 12)); + OPTIMIZER_HIDE_VAR(neq); + } else +#endif /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */ + { + neq |= *(unsigned char *)(a) ^ *(unsigned char *)(b); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+1) ^ *(unsigned char *)(b+1); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+2) ^ *(unsigned char *)(b+2); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+3) ^ *(unsigned char *)(b+3); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+4) ^ *(unsigned char *)(b+4); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+5) ^ *(unsigned char *)(b+5); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+6) ^ *(unsigned char *)(b+6); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+7) ^ *(unsigned char *)(b+7); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+8) ^ *(unsigned char *)(b+8); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+9) ^ *(unsigned char *)(b+9); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+10) ^ *(unsigned char *)(b+10); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+11) ^ *(unsigned char *)(b+11); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+12) ^ *(unsigned char *)(b+12); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+13) ^ *(unsigned char *)(b+13); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+14) ^ *(unsigned char *)(b+14); + OPTIMIZER_HIDE_VAR(neq); + neq |= *(unsigned char *)(a+15) ^ *(unsigned char *)(b+15); + OPTIMIZER_HIDE_VAR(neq); + } + + return neq; +} + +/* Compare two areas of memory without leaking timing information, + * and with special optimizations for common sizes. Users should + * not call this function directly, but should instead use + * crypto_memneq defined in crypto/utils.h. + */ +noinline unsigned long __crypto_memneq(const void *a, const void *b, + size_t size) +{ + switch (size) { + case 16: + return __crypto_memneq_16(a, b); + default: + return __crypto_memneq_generic(a, b, size); + } +} +EXPORT_SYMBOL(__crypto_memneq); -- cgit v1.3.1