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Revision 7ff57e98fb78ad94edafbdc7435f2d745e9e6bb5 authored by Fabio M. De Francesco on 23 February 2022, 10:02:52 UTC, committed by Jakub Kicinski on 24 February 2022, 17:09:33 UTC 
net/smc: Use a mutex for locking "struct smc_pnettable"
 
smc_pnetid_by_table_ib() uses read_lock() and then it calls smc_pnet_apply_ib()
which, in turn, calls mutex_lock(&smc_ib_devices.mutex).

read_lock() disables preemption. Therefore, the code acquires a mutex while in
atomic context and it leads to a SAC bug.

Fix this bug by replacing the rwlock with a mutex.

Reported-and-tested-by: syzbot+4f322a6d84e991c38775@syzkaller.appspotmail.com
Fixes: 64e28b52c7a6 ("net/smc: add pnet table namespace support")
Confirmed-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Link: https://lore.kernel.org/r/20220223100252.22562-1-fmdefrancesco@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Raw File
audit.c 
// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/types.h>
#include <linux/audit.h>
#include <asm/unistd.h>

static unsigned dir_class[] = {
#include <asm-generic/audit_dir_write.h>
~0U
};

static unsigned read_class[] = {
#include <asm-generic/audit_read.h>
~0U
};

static unsigned write_class[] = {
#include <asm-generic/audit_write.h>
~0U
};

static unsigned chattr_class[] = {
#include <asm-generic/audit_change_attr.h>
~0U
};

static unsigned signal_class[] = {
#include <asm-generic/audit_signal.h>
~0U
};

int audit_classify_arch(int arch)
{
	if (audit_is_compat(arch))
		return 1;
	else
		return 0;
}

int audit_classify_syscall(int abi, unsigned syscall)
{
	if (audit_is_compat(abi))
		return audit_classify_compat_syscall(abi, syscall);

	switch(syscall) {
#ifdef __NR_open
	case __NR_open:
		return AUDITSC_OPEN;
#endif
#ifdef __NR_openat
	case __NR_openat:
		return AUDITSC_OPENAT;
#endif
#ifdef __NR_socketcall
	case __NR_socketcall:
		return AUDITSC_SOCKETCALL;
#endif
#ifdef __NR_execveat
	case __NR_execveat:
#endif
	case __NR_execve:
		return AUDITSC_EXECVE;
#ifdef __NR_openat2
	case __NR_openat2:
		return AUDITSC_OPENAT2;
#endif
	default:
		return AUDITSC_NATIVE;
	}
}

static int __init audit_classes_init(void)
{
#ifdef CONFIG_AUDIT_COMPAT_GENERIC
	audit_register_class(AUDIT_CLASS_WRITE_32, compat_write_class);
	audit_register_class(AUDIT_CLASS_READ_32, compat_read_class);
	audit_register_class(AUDIT_CLASS_DIR_WRITE_32, compat_dir_class);
	audit_register_class(AUDIT_CLASS_CHATTR_32, compat_chattr_class);
	audit_register_class(AUDIT_CLASS_SIGNAL_32, compat_signal_class);
#endif
	audit_register_class(AUDIT_CLASS_WRITE, write_class);
	audit_register_class(AUDIT_CLASS_READ, read_class);
	audit_register_class(AUDIT_CLASS_DIR_WRITE, dir_class);
	audit_register_class(AUDIT_CLASS_CHATTR, chattr_class);
	audit_register_class(AUDIT_CLASS_SIGNAL, signal_class);
	return 0;
}

__initcall(audit_classes_init);
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