* Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
2020-07-21 14:38 [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx() Yang Yingliang
@ 2020-07-21 10:48 ` Greg KH
2020-07-21 11:54 ` Yang Yingliang
2020-07-22 1:56 ` liwei (GF)
1 sibling, 1 reply; 6+ messages in thread
From: Greg KH @ 2020-07-21 10:48 UTC (permalink / raw)
To: Yang Yingliang; +Cc: linux-serial, linux-kernel, jslaby
On Tue, Jul 21, 2020 at 02:38:52PM +0000, Yang Yingliang wrote:
> I got null-ptr-deref in serial8250_start_tx():
>
> [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> [ 78.123778] Mem abort info:
> [ 78.126560] ESR = 0x86000007
> [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits
> [ 78.134891] SET = 0, FnV = 0
> [ 78.137933] EA = 0, S1PTW = 0
> [ 78.141064] user pgtable: 64k pages, 48-bit VAs, pgdp=00000027d41a8600
> [ 78.147562] [0000000000000000] pgd=00000027893f0003, p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003, pte=0000000000000000
> [ 78.160029] Internal error: Oops: 86000007 [#1] SMP
> [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci hisi_sas_main libsas hns3 scsi_transport_sas hclge libata megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd
> [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted 5.8.0-rc6+ #48
> [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B210.01 03/12/2020
> [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
> [ 78.228435] pc : 0x0
> [ 78.230618] lr : serial8250_start_tx+0x160/0x260
> [ 78.235215] sp : ffff800062eefb80
> [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff
> [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000
> [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000
> [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002
> [ 78.259679] x21: 0000000000000001 x20: 0000000000000000
> [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000
> [ 78.270259] x17: 0000000000000000 x16: 0000000000000000
> [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6
> [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539
> [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0
> [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88
> [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000
> [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8
> [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002
> [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8
> [ 78.317873] Call trace:
> [ 78.320312] 0x0
> [ 78.322147] __uart_start.isra.9+0x64/0x78
> [ 78.326229] uart_start+0xb8/0x1c8
> [ 78.329620] uart_flush_chars+0x24/0x30
> [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30
> [ 78.338128] n_tty_receive_buf+0x44/0x2c8
> [ 78.342122] tty_ioctl+0x348/0x11f8
> [ 78.345599] ksys_ioctl+0xd8/0xf8
> [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8
> [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0
> [ 78.357583] do_el0_svc+0x44/0xd0
> [ 78.360887] el0_sync_handler+0x14c/0x1d0
> [ 78.364880] el0_sync+0x140/0x180
> [ 78.368185] Code: bad PC value
>
> SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
> serial8250_set_defaults() won't be called in serial8250_isa_init_ports(),
> so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref.
> Fix this problem by calling serial8250_set_defaults() after init uart port.
>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> drivers/tty/serial/8250/8250_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Does this fix a specific commit, or has this issue always been present?
What has caused it to happen now that no one else has seen this?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
2020-07-21 10:48 ` Greg KH
@ 2020-07-21 11:54 ` Yang Yingliang
2020-07-21 12:18 ` Yang Yingliang
0 siblings, 1 reply; 6+ messages in thread
From: Yang Yingliang @ 2020-07-21 11:54 UTC (permalink / raw)
To: Greg KH; +Cc: linux-serial, linux-kernel, jslaby, Hanjun Guo, Libin (Huawei)
On 2020/7/21 18:48, Greg KH wrote:
> On Tue, Jul 21, 2020 at 02:38:52PM +0000, Yang Yingliang wrote:
>> I got null-ptr-deref in serial8250_start_tx():
>>
>> [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
>> [ 78.123778] Mem abort info:
>> [ 78.126560] ESR = 0x86000007
>> [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits
>> [ 78.134891] SET = 0, FnV = 0
>> [ 78.137933] EA = 0, S1PTW = 0
>> [ 78.141064] user pgtable: 64k pages, 48-bit VAs, pgdp=00000027d41a8600
>> [ 78.147562] [0000000000000000] pgd=00000027893f0003, p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003, pte=0000000000000000
>> [ 78.160029] Internal error: Oops: 86000007 [#1] SMP
>> [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci hisi_sas_main libsas hns3 scsi_transport_sas hclge libata megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd
>> [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted 5.8.0-rc6+ #48
>> [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B210.01 03/12/2020
>> [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
>> [ 78.228435] pc : 0x0
>> [ 78.230618] lr : serial8250_start_tx+0x160/0x260
>> [ 78.235215] sp : ffff800062eefb80
>> [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff
>> [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000
>> [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000
>> [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002
>> [ 78.259679] x21: 0000000000000001 x20: 0000000000000000
>> [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000
>> [ 78.270259] x17: 0000000000000000 x16: 0000000000000000
>> [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6
>> [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539
>> [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0
>> [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88
>> [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000
>> [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8
>> [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002
>> [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8
>> [ 78.317873] Call trace:
>> [ 78.320312] 0x0
>> [ 78.322147] __uart_start.isra.9+0x64/0x78
>> [ 78.326229] uart_start+0xb8/0x1c8
>> [ 78.329620] uart_flush_chars+0x24/0x30
>> [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30
>> [ 78.338128] n_tty_receive_buf+0x44/0x2c8
>> [ 78.342122] tty_ioctl+0x348/0x11f8
>> [ 78.345599] ksys_ioctl+0xd8/0xf8
>> [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8
>> [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0
>> [ 78.357583] do_el0_svc+0x44/0xd0
>> [ 78.360887] el0_sync_handler+0x14c/0x1d0
>> [ 78.364880] el0_sync+0x140/0x180
>> [ 78.368185] Code: bad PC value
>>
>> SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
>> serial8250_set_defaults() won't be called in serial8250_isa_init_ports(),
>> so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref.
>> Fix this problem by calling serial8250_set_defaults() after init uart port.
>>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> drivers/tty/serial/8250/8250_core.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
> Does this fix a specific commit, or has this issue always been present?
> What has caused it to happen now that no one else has seen this?
I think it's always been present on the arch that not defined
SERIAL_PORT_DFNS.
I got this on arm64 and here is the C reproducer:
// autogenerated by syzkaller (https://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <endian.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#ifndef __NR_ioctl
#define __NR_ioctl 29
#endif
#ifndef __NR_mmap
#define __NR_mmap 222
#endif
#ifndef __NR_openat
#define __NR_openat 56
#endif
uint64_t r[1] = {0xffffffffffffffff};
int main(void)
{
syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
intptr_t res = 0;
memcpy((void*)0x20000040, "/dev/ttyS3\000", 11);
res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000040ul,
0x401ul, 0ul);
if (res != -1)
r[0] = res;
syscall(__NR_ioctl, r[0], 0x5412ul, 0x20000080ul);
return 0;
}
Thanks,
Yang
>
> thanks,
>
> greg k-h
> .
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
2020-07-21 11:54 ` Yang Yingliang
@ 2020-07-21 12:18 ` Yang Yingliang
2020-07-21 19:11 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Yang Yingliang @ 2020-07-21 12:18 UTC (permalink / raw)
To: Greg KH; +Cc: linux-serial, linux-kernel, jslaby, Hanjun Guo, Libin (Huawei)
On 2020/7/21 19:54, Yang Yingliang wrote:
>
> On 2020/7/21 18:48, Greg KH wrote:
>> On Tue, Jul 21, 2020 at 02:38:52PM +0000, Yang Yingliang wrote:
>>> I got null-ptr-deref in serial8250_start_tx():
>>>
>>> [ 78.114630] Unable to handle kernel NULL pointer dereference at
>>> virtual address 0000000000000000
>>> [ 78.123778] Mem abort info:
>>> [ 78.126560] ESR = 0x86000007
>>> [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits
>>> [ 78.134891] SET = 0, FnV = 0
>>> [ 78.137933] EA = 0, S1PTW = 0
>>> [ 78.141064] user pgtable: 64k pages, 48-bit VAs,
>>> pgdp=00000027d41a8600
>>> [ 78.147562] [0000000000000000] pgd=00000027893f0003,
>>> p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003,
>>> pte=0000000000000000
>>> [ 78.160029] Internal error: Oops: 86000007 [#1] SMP
>>> [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk
>>> crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce
>>> sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif
>>> spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap
>>> ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci
>>> hisi_sas_main libsas hns3 scsi_transport_sas hclge libata
>>> megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter
>>> bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd
>>> [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted
>>> 5.8.0-rc6+ #48
>>> [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS
>>> 2280-V2 CS V3.B210.01 03/12/2020
>>> [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
>>> [ 78.228435] pc : 0x0
>>> [ 78.230618] lr : serial8250_start_tx+0x160/0x260
>>> [ 78.235215] sp : ffff800062eefb80
>>> [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff
>>> [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000
>>> [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000
>>> [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002
>>> [ 78.259679] x21: 0000000000000001 x20: 0000000000000000
>>> [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000
>>> [ 78.270259] x17: 0000000000000000 x16: 0000000000000000
>>> [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6
>>> [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539
>>> [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0
>>> [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88
>>> [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000
>>> [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8
>>> [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002
>>> [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8
>>> [ 78.317873] Call trace:
>>> [ 78.320312] 0x0
>>> [ 78.322147] __uart_start.isra.9+0x64/0x78
>>> [ 78.326229] uart_start+0xb8/0x1c8
>>> [ 78.329620] uart_flush_chars+0x24/0x30
>>> [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30
>>> [ 78.338128] n_tty_receive_buf+0x44/0x2c8
>>> [ 78.342122] tty_ioctl+0x348/0x11f8
>>> [ 78.345599] ksys_ioctl+0xd8/0xf8
>>> [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8
>>> [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0
>>> [ 78.357583] do_el0_svc+0x44/0xd0
>>> [ 78.360887] el0_sync_handler+0x14c/0x1d0
>>> [ 78.364880] el0_sync+0x140/0x180
>>> [ 78.368185] Code: bad PC value
>>>
>>> SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
>>> serial8250_set_defaults() won't be called in
>>> serial8250_isa_init_ports(),
>>> so the p->serial_in pointer won't be initialized, and it leads a
>>> null-ptr-deref.
>>> Fix this problem by calling serial8250_set_defaults() after init
>>> uart port.
>>>
>>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>>> ---
>>> drivers/tty/serial/8250/8250_core.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> Does this fix a specific commit, or has this issue always been present?
>> What has caused it to happen now that no one else has seen this?
>
> I think it's always been present on the arch that not defined
> SERIAL_PORT_DFNS.
>
> I got this on arm64 and here is the C reproducer:
>
> // autogenerated by syzkaller (https://github.com/google/syzkaller)
>
> #define _GNU_SOURCE
>
> #include <endian.h>
> #include <stdint.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <sys/syscall.h>
> #include <sys/types.h>
> #include <unistd.h>
>
> #ifndef __NR_ioctl
> #define __NR_ioctl 29
> #endif
> #ifndef __NR_mmap
> #define __NR_mmap 222
> #endif
> #ifndef __NR_openat
> #define __NR_openat 56
> #endif
>
> uint64_t r[1] = {0xffffffffffffffff};
>
> int main(void)
> {
> syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
> intptr_t res = 0;
> memcpy((void*)0x20000040, "/dev/ttyS3\000", 11);
> res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000040ul,
> 0x401ul, 0ul);
> if (res != -1)
> r[0] = res;
> syscall(__NR_ioctl, r[0], 0x5412ul, 0x20000080ul);
> return 0;
> }
>
It's can be reproduced with CONFIG_SERIAL_8250_RUNTIME_UARTS=8 and
by opening ttyS4 on x86_64. Because the size of SERIAL_PORT_DFNS is 4 and
the pointers of ttyS4 ~ ttyS7 won't be initialized.
[ 49.427884] BUG: unable to handle kernel NULL pointer dereference at
0000000000000000
[ 49.432786] PGD 80000003d7573067 P4D 80000003d7573067 PUD 3d7526067 PMD 0
[ 49.436944] Oops: 0010 [#1] SMP KASAN PTI
[ 49.439490] CPU: 1 PID: 2491 Comm: test Not tainted 4.19.90+ #1083
[ 49.443437] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[ 49.450233] RIP: 0010: (null)
[ 49.452279] Code: Bad RIP value.
[ 49.454066] RSP: 0018:ffff8883d73a7880 EFLAGS: 00010093
[ 49.457082] RAX: ffff8883d72d6000 RBX: ffffffff85e243a0 RCX:
ffffffff820a062b
[ 49.460916] RDX: 0000000000000002 RSI: 0000000000000001 RDI:
ffffffff85e243a0
[ 49.464490] RBP: 0000000000000002 R08: fffffbfff0bc4875 R09:
fffffbfff0bc4874
[ 49.467993] R10: fffffbfff0bc4874 R11: ffffffff85e243a3 R12:
ffffffff85e245f6
[ 49.471526] R13: ffffffff85e243f0 R14: 0000000000000000 R15:
0000000000000000
[ 49.475192] FS: 0000000002064880(0000) GS:ffff8883eb240000(0000)
knlGS:0000000000000000
[ 49.479019] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 49.481852] CR2: ffffffffffffffd6 CR3: 00000003d77a2006 CR4:
0000000000020ee0
[ 49.485131] Call Trace:
[ 49.486278] serial8250_start_tx+0x56c/0x9b0
[ 49.488167] __uart_start.isra.1+0x16a/0x1b0
[ 49.490082] uart_start+0x1a7/0x340
[ 49.491650] ? __uart_start.isra.1+0x1b0/0x1b0
[ 49.493670] ? __process_echoes+0x636/0x860
[ 49.495540] ? uart_start+0x340/0x340
[ 49.497442] n_tty_receive_buf_common+0x10ff/0x2460
[ 49.499897] ? n_tty_receive_buf2+0x40/0x40
[ 49.501915] tty_ioctl+0x6e1/0x1400
[ 49.503629] ? quarantine_put+0xb7/0x150
[ 49.505474] ? tty_vhangup+0x30/0x30
[ 49.507237] ? lockdep_hardirqs_on+0x290/0x560
[ 49.509419] ? __kasan_slab_free+0x1ce/0x230
[ 49.511490] ? kmem_cache_free+0xa6/0x2a0
[ 49.513454] ? putname+0xd4/0x110
[ 49.515059] ? do_sys_open+0x291/0x3f0
[ 49.516888] ? do_syscall_64+0x11c/0xe08
[ 49.518795] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 49.521359] ? __lock_acquire+0x5eb/0x2e50
[ 49.523278] ? restore_nameidata+0x108/0x180
[ 49.525242] ? tty_vhangup+0x30/0x30
[ 49.526895] do_vfs_ioctl+0x1a5/0x1100
[ 49.528608] ? may_open_dev+0xd0/0xd0
[ 49.530414] ? ioctl_preallocate+0x1d0/0x1d0
[ 49.532607] ? putname+0xd4/0x110
[ 49.534097] ? rcu_read_lock_sched_held+0x114/0x130
[ 49.536342] ? kmem_cache_free+0x263/0x2a0
[ 49.538450] ? putname+0xd4/0x110
[ 49.540036] ? do_sys_open+0x1ec/0x3f0
[ 49.541909] ksys_ioctl+0x7c/0xa0
[ 49.543458] __x64_sys_ioctl+0x74/0xb0
[ 49.545433] ? lockdep_hardirqs_on+0x37c/0x560
[ 49.547642] do_syscall_64+0x11c/0xe08
[ 49.549447] ? syscall_return_slowpath+0x3a0/0x3a0
[ 49.551741] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 49.553810] ? trace_hardirqs_off_caller+0x54/0x190
[ 49.556125] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 49.558453] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Thanks,
>
> Yang
>
>>
>> thanks,
>>
>> greg k-h
>> .
>
> .
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
@ 2020-07-21 14:38 Yang Yingliang
2020-07-21 10:48 ` Greg KH
2020-07-22 1:56 ` liwei (GF)
0 siblings, 2 replies; 6+ messages in thread
From: Yang Yingliang @ 2020-07-21 14:38 UTC (permalink / raw)
To: linux-serial, linux-kernel; +Cc: gregkh, jslaby, yangyingliang
I got null-ptr-deref in serial8250_start_tx():
[ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[ 78.123778] Mem abort info:
[ 78.126560] ESR = 0x86000007
[ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits
[ 78.134891] SET = 0, FnV = 0
[ 78.137933] EA = 0, S1PTW = 0
[ 78.141064] user pgtable: 64k pages, 48-bit VAs, pgdp=00000027d41a8600
[ 78.147562] [0000000000000000] pgd=00000027893f0003, p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003, pte=0000000000000000
[ 78.160029] Internal error: Oops: 86000007 [#1] SMP
[ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci hisi_sas_main libsas hns3 scsi_transport_sas hclge libata megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd
[ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted 5.8.0-rc6+ #48
[ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B210.01 03/12/2020
[ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
[ 78.228435] pc : 0x0
[ 78.230618] lr : serial8250_start_tx+0x160/0x260
[ 78.235215] sp : ffff800062eefb80
[ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff
[ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000
[ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000
[ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002
[ 78.259679] x21: 0000000000000001 x20: 0000000000000000
[ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000
[ 78.270259] x17: 0000000000000000 x16: 0000000000000000
[ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6
[ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539
[ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0
[ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88
[ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000
[ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8
[ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002
[ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8
[ 78.317873] Call trace:
[ 78.320312] 0x0
[ 78.322147] __uart_start.isra.9+0x64/0x78
[ 78.326229] uart_start+0xb8/0x1c8
[ 78.329620] uart_flush_chars+0x24/0x30
[ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30
[ 78.338128] n_tty_receive_buf+0x44/0x2c8
[ 78.342122] tty_ioctl+0x348/0x11f8
[ 78.345599] ksys_ioctl+0xd8/0xf8
[ 78.348903] __arm64_sys_ioctl+0x2c/0xc8
[ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0
[ 78.357583] do_el0_svc+0x44/0xd0
[ 78.360887] el0_sync_handler+0x14c/0x1d0
[ 78.364880] el0_sync+0x140/0x180
[ 78.368185] Code: bad PC value
SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
serial8250_set_defaults() won't be called in serial8250_isa_init_ports(),
so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref.
Fix this problem by calling serial8250_set_defaults() after init uart port.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
drivers/tty/serial/8250/8250_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index fc118f649887..cae61d1ebec5 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -524,6 +524,7 @@ static void __init serial8250_isa_init_ports(void)
*/
up->mcr_mask = ~ALPHA_KLUDGE_MCR;
up->mcr_force = ALPHA_KLUDGE_MCR;
+ serial8250_set_defaults(up);
}
/* chain base port ops to support Remote Supervisor Adapter */
@@ -547,7 +548,6 @@ static void __init serial8250_isa_init_ports(void)
port->membase = old_serial_port[i].iomem_base;
port->iotype = old_serial_port[i].io_type;
port->regshift = old_serial_port[i].iomem_reg_shift;
- serial8250_set_defaults(up);
port->irqflags |= irqflag;
if (serial8250_isa_config != NULL)
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
2020-07-21 12:18 ` Yang Yingliang
@ 2020-07-21 19:11 ` Greg KH
0 siblings, 0 replies; 6+ messages in thread
From: Greg KH @ 2020-07-21 19:11 UTC (permalink / raw)
To: Yang Yingliang
Cc: linux-serial, linux-kernel, jslaby, Hanjun Guo, Libin (Huawei)
On Tue, Jul 21, 2020 at 08:18:11PM +0800, Yang Yingliang wrote:
>
> On 2020/7/21 19:54, Yang Yingliang wrote:
> >
> > On 2020/7/21 18:48, Greg KH wrote:
> > > On Tue, Jul 21, 2020 at 02:38:52PM +0000, Yang Yingliang wrote:
> > > > I got null-ptr-deref in serial8250_start_tx():
> > > >
> > > > [ 78.114630] Unable to handle kernel NULL pointer dereference
> > > > at virtual address 0000000000000000
> > > > [ 78.123778] Mem abort info:
> > > > [ 78.126560] ESR = 0x86000007
> > > > [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits
> > > > [ 78.134891] SET = 0, FnV = 0
> > > > [ 78.137933] EA = 0, S1PTW = 0
> > > > [ 78.141064] user pgtable: 64k pages, 48-bit VAs,
> > > > pgdp=00000027d41a8600
> > > > [ 78.147562] [0000000000000000] pgd=00000027893f0003,
> > > > p4d=00000027893f0003, pud=00000027893f0003,
> > > > pmd=00000027c9a20003, pte=0000000000000000
> > > > [ 78.160029] Internal error: Oops: 86000007 [#1] SMP
> > > > [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk
> > > > crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce
> > > > sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif
> > > > spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap
> > > > ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci
> > > > hisi_sas_main libsas hns3 scsi_transport_sas hclge libata
> > > > megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler
> > > > br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp
> > > > libcrc32c dm_mod nbd
> > > > [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted
> > > > 5.8.0-rc6+ #48
> > > > [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC,
> > > > BIOS 2280-V2 CS V3.B210.01 03/12/2020
> > > > [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
> > > > [ 78.228435] pc : 0x0
> > > > [ 78.230618] lr : serial8250_start_tx+0x160/0x260
> > > > [ 78.235215] sp : ffff800062eefb80
> > > > [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff
> > > > [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000
> > > > [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000
> > > > [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002
> > > > [ 78.259679] x21: 0000000000000001 x20: 0000000000000000
> > > > [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000
> > > > [ 78.270259] x17: 0000000000000000 x16: 0000000000000000
> > > > [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6
> > > > [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539
> > > > [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0
> > > > [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88
> > > > [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000
> > > > [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8
> > > > [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002
> > > > [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8
> > > > [ 78.317873] Call trace:
> > > > [ 78.320312] 0x0
> > > > [ 78.322147] __uart_start.isra.9+0x64/0x78
> > > > [ 78.326229] uart_start+0xb8/0x1c8
> > > > [ 78.329620] uart_flush_chars+0x24/0x30
> > > > [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30
> > > > [ 78.338128] n_tty_receive_buf+0x44/0x2c8
> > > > [ 78.342122] tty_ioctl+0x348/0x11f8
> > > > [ 78.345599] ksys_ioctl+0xd8/0xf8
> > > > [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8
> > > > [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0
> > > > [ 78.357583] do_el0_svc+0x44/0xd0
> > > > [ 78.360887] el0_sync_handler+0x14c/0x1d0
> > > > [ 78.364880] el0_sync+0x140/0x180
> > > > [ 78.368185] Code: bad PC value
> > > >
> > > > SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
> > > > serial8250_set_defaults() won't be called in
> > > > serial8250_isa_init_ports(),
> > > > so the p->serial_in pointer won't be initialized, and it leads a
> > > > null-ptr-deref.
> > > > Fix this problem by calling serial8250_set_defaults() after init
> > > > uart port.
> > > >
> > > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > > > ---
> > > > drivers/tty/serial/8250/8250_core.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > Does this fix a specific commit, or has this issue always been present?
> > > What has caused it to happen now that no one else has seen this?
> >
> > I think it's always been present on the arch that not defined
> > SERIAL_PORT_DFNS.
> >
> > I got this on arm64 and here is the C reproducer:
> >
> > // autogenerated by syzkaller (https://github.com/google/syzkaller)
> >
> > #define _GNU_SOURCE
> >
> > #include <endian.h>
> > #include <stdint.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <string.h>
> > #include <sys/syscall.h>
> > #include <sys/types.h>
> > #include <unistd.h>
> >
> > #ifndef __NR_ioctl
> > #define __NR_ioctl 29
> > #endif
> > #ifndef __NR_mmap
> > #define __NR_mmap 222
> > #endif
> > #ifndef __NR_openat
> > #define __NR_openat 56
> > #endif
> >
> > uint64_t r[1] = {0xffffffffffffffff};
> >
> > int main(void)
> > {
> > syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
> > intptr_t res = 0;
> > memcpy((void*)0x20000040, "/dev/ttyS3\000", 11);
> > res = syscall(__NR_openat, 0xffffffffffffff9cul, 0x20000040ul,
> > 0x401ul, 0ul);
> > if (res != -1)
> > r[0] = res;
> > syscall(__NR_ioctl, r[0], 0x5412ul, 0x20000080ul);
> > return 0;
> > }
> >
> It's can be reproduced with CONFIG_SERIAL_8250_RUNTIME_UARTS=8 and
>
> by opening ttyS4 on x86_64. Because the size of SERIAL_PORT_DFNS is 4 and
>
> the pointers of ttyS4 ~ ttyS7 won't be initialized.
Ah, good catch, yeah, that's not nice. I'll go queue this up now,
thanks for the fix!
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
2020-07-21 14:38 [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx() Yang Yingliang
2020-07-21 10:48 ` Greg KH
@ 2020-07-22 1:56 ` liwei (GF)
1 sibling, 0 replies; 6+ messages in thread
From: liwei (GF) @ 2020-07-22 1:56 UTC (permalink / raw)
To: Yang Yingliang, gregkh; +Cc: jslaby, LKML, linux-serial
Hi Yingliang,
On 2020/7/21 22:38, Yang Yingliang wrote:
(SNIP)
>
> SERIAL_PORT_DFNS is not defined on each arch, if it's not defined,
> serial8250_set_defaults() won't be called in serial8250_isa_init_ports(),
> so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref.
> Fix this problem by calling serial8250_set_defaults() after init uart port.
>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> drivers/tty/serial/8250/8250_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index fc118f649887..cae61d1ebec5 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -524,6 +524,7 @@ static void __init serial8250_isa_init_ports(void)
> */
> up->mcr_mask = ~ALPHA_KLUDGE_MCR;
> up->mcr_force = ALPHA_KLUDGE_MCR;
> + serial8250_set_defaults(up);
That is really a good catch, but this modification looks not good to me.
First, serial8250_set_defaults()'s parameter 'up' updated in the loop below is used to
lead to different branch in this function. So that the logic is broken.
Second, up->port.iobase and up->port.iotype are both initialized to 0, so the 'serial_in'
and 'serial_out' will be assigned to the ops for IO space with port 0 here, i don't think
that is correct.
> }
>
> /* chain base port ops to support Remote Supervisor Adapter */
> @@ -547,7 +548,6 @@ static void __init serial8250_isa_init_ports(void)
> port->membase = old_serial_port[i].iomem_base;
> port->iotype = old_serial_port[i].io_type;
> port->regshift = old_serial_port[i].iomem_reg_shift;
> - serial8250_set_defaults(up);
>
> port->irqflags |= irqflag;
> if (serial8250_isa_config != NULL)
>
Thanks,
Wei
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-07-22 2:03 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-21 14:38 [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx() Yang Yingliang
2020-07-21 10:48 ` Greg KH
2020-07-21 11:54 ` Yang Yingliang
2020-07-21 12:18 ` Yang Yingliang
2020-07-21 19:11 ` Greg KH
2020-07-22 1:56 ` liwei (GF)
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