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Revision 9c55ad1c214d9f8c4594ac2c3fa392c1c32431a7 authored by Ilya Dryomov on 24 April 2018, 17:10:55 UTC, committed by Ilya Dryomov on 26 April 2018, 15:39:08 UTC 
libceph: validate con->state at the top of try_write()
 
ceph_con_workfn() validates con->state before calling try_read() and
then try_write().  However, try_read() temporarily releases con->mutex,
notably in process_message() and ceph_con_in_msg_alloc(), opening the
window for ceph_con_close() to sneak in, close the connection and
release con->sock.  When try_write() is called on the assumption that
con->state is still valid (i.e. not STANDBY or CLOSED), a NULL sock
gets passed to the networking stack:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
  IP: selinux_socket_sendmsg+0x5/0x20

Make sure con->state is valid at the top of try_write() and add an
explicit BUG_ON for this, similar to try_read().

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/23706
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
1 parent 7b4c443
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 2;
#endif
#ifdef __NR_openat
	case __NR_openat:
		return 3;
#endif
#ifdef __NR_socketcall
	case __NR_socketcall:
		return 4;
#endif
#ifdef __NR_execveat
	case __NR_execveat:
#endif
	case __NR_execve:
		return 5;
	default:
		return 0;
	}
}

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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