Commit dc5110c2 authored by YueHaibing's avatar YueHaibing Committed by David S. Miller

tcp: restrict net.ipv4.tcp_app_win

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-g62bad54b-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>
parent 8ce07be7
......@@ -340,6 +340,8 @@ 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
......
......@@ -25,6 +25,7 @@ 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;
......@@ -1198,6 +1199,8 @@ static struct ctl_table ipv4_net_table[] = {
.maxlen = sizeof(u8),
.mode = 0644,
.proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &tcp_app_win_max,
},
{
.procname = "tcp_adv_win_scale",
......
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