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Revision e96d71359e9bbea846a2111e4469a03a055dfa6f authored by Mathieu Desnoyers on 09 July 2018, 19:51:50 UTC, committed by Thomas Gleixner on 10 July 2018, 20:18:51 UTC 
rseq: Use __u64 for rseq_cs fields, validate user inputs
 
Change the rseq ABI so rseq_cs start_ip, post_commit_offset and abort_ip
fields are seen as 64-bit fields by both 32-bit and 64-bit kernels rather
that ignoring the 32 upper bits on 32-bit kernels. This ensures we have a
consistent behavior for a 32-bit binary executed on 32-bit kernels and in
compat mode on 64-bit kernels.

Validating the value of abort_ip field to be below TASK_SIZE ensures the
kernel don't return to an invalid address when returning to userspace
after an abort. I don't fully trust each architecture code to consistently
deal with invalid return addresses.

Validating the value of the start_ip and post_commit_offset fields
prevents overflow on arithmetic performed on those values, used to
check whether abort_ip is within the rseq critical section.

If validation fails, the process is killed with a segmentation fault.

When the signature encountered before abort_ip does not match the expected
signature, return -EINVAL rather than -EPERM to be consistent with other
input validation return codes from rseq_get_rseq_cs().

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-api@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Paul Turner <pjt@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Chris Lameter <cl@linux.com>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180709195155.7654-2-mathieu.desnoyers@efficios.com
1 parent 1e4b044
Raw File
proc.c 
/*
 * Scatterlist Cryptographic API.
 *
 * Procfs information.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option) 
 * any later version.
 *
 */

#include <linux/atomic.h>
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/module.h>	/* for module_name() */
#include <linux/rwsem.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include "internal.h"

static void *c_start(struct seq_file *m, loff_t *pos)
{
	down_read(&crypto_alg_sem);
	return seq_list_start(&crypto_alg_list, *pos);
}

static void *c_next(struct seq_file *m, void *p, loff_t *pos)
{
	return seq_list_next(p, &crypto_alg_list, pos);
}

static void c_stop(struct seq_file *m, void *p)
{
	up_read(&crypto_alg_sem);
}

static int c_show(struct seq_file *m, void *p)
{
	struct crypto_alg *alg = list_entry(p, struct crypto_alg, cra_list);
	
	seq_printf(m, "name         : %s\n", alg->cra_name);
	seq_printf(m, "driver       : %s\n", alg->cra_driver_name);
	seq_printf(m, "module       : %s\n", module_name(alg->cra_module));
	seq_printf(m, "priority     : %d\n", alg->cra_priority);
	seq_printf(m, "refcnt       : %u\n", refcount_read(&alg->cra_refcnt));
	seq_printf(m, "selftest     : %s\n",
		   (alg->cra_flags & CRYPTO_ALG_TESTED) ?
		   "passed" : "unknown");
	seq_printf(m, "internal     : %s\n",
		   (alg->cra_flags & CRYPTO_ALG_INTERNAL) ?
		   "yes" : "no");

	if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
		seq_printf(m, "type         : larval\n");
		seq_printf(m, "flags        : 0x%x\n", alg->cra_flags);
		goto out;
	}

	if (alg->cra_type && alg->cra_type->show) {
		alg->cra_type->show(m, alg);
		goto out;
	}
	
	switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		seq_printf(m, "type         : cipher\n");
		seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
		seq_printf(m, "min keysize  : %u\n",
					alg->cra_cipher.cia_min_keysize);
		seq_printf(m, "max keysize  : %u\n",
					alg->cra_cipher.cia_max_keysize);
		break;
	case CRYPTO_ALG_TYPE_COMPRESS:
		seq_printf(m, "type         : compression\n");
		break;
	default:
		seq_printf(m, "type         : unknown\n");
		break;
	}

out:
	seq_putc(m, '\n');
	return 0;
}

static const struct seq_operations crypto_seq_ops = {
	.start		= c_start,
	.next		= c_next,
	.stop		= c_stop,
	.show		= c_show
};

void __init crypto_init_proc(void)
{
	proc_create_seq("crypto", 0, NULL, &crypto_seq_ops);
}

void __exit crypto_exit_proc(void)
{
	remove_proc_entry("crypto", NULL);
}
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