Commit bb54ca93 authored by YueHaibing's avatar YueHaibing
Browse files

tcp: restrict net.ipv4.tcp_app_win 

mainline inclusion
from mainline-v6.3-rc7
commit dc5110c2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6WB6P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dc5110c2d959c1707e12df5f792f41d90614adaa



--------------------------------

UBSAN: shift-out-of-bounds in net/ipv4/tcp_input.c:555:23
shift exponent 255 is too large for 32-bit type 'int'
CPU: 1 PID: 7907 Comm: ssh Not tainted 6.3.0-rc4-00161-g62bad54b26db-dirty #206
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x136/0x150
 __ubsan_handle_shift_out_of_bounds+0x21f/0x5a0
 tcp_init_transfer.cold+0x3a/0xb9
 tcp_finish_connect+0x1d0/0x620
 tcp_rcv_state_process+0xd78/0x4d60
 tcp_v4_do_rcv+0x33d/0x9d0
 __release_sock+0x133/0x3b0
 release_sock+0x58/0x1b0

'maxwin' is int, shifting int for 32 or more bits is undefined behaviour.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarYueHaibing <yuehaibing@huawei.com>
parent 5d1a3d3e

Documentation/networking/ip-sysctl.rst

+2 −0
Original line number Diff line number Diff line
@@ -272,6 +272,8 @@ tcp_app_win - INTEGER 
	Reserve max(window/2^tcp_app_win, mss) of window for application

	buffer. Value 0 is special, it means that nothing is reserved.



	Possible values are [0, 31], inclusive.



	Default: 31



tcp_autocorking - BOOLEAN

net/ipv4/sysctl_net_ipv4.c

+4 −1
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ static int ip_local_port_range_min[] = { 1, 1 }; 
static int ip_local_port_range_max[] = { 65535, 65535 };

static int tcp_adv_win_scale_min = -31;

static int tcp_adv_win_scale_max = 31;

static int tcp_app_win_max = 31;

static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;

static int tcp_min_snd_mss_max = 65535;

static int ip_privileged_port_min;
@@ -1164,7 +1165,9 @@ static struct ctl_table ipv4_net_table[] = { 
		.data		= &init_net.ipv4.sysctl_tcp_app_win,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= SYSCTL_ZERO,

		.extra2		= &tcp_app_win_max,

	},

	{

		.procname	= "tcp_adv_win_scale",