Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
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 > --- > 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
Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
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 +, Yang Yingliang wrote:
> > > > I got null-ptr-deref in serial8250_start_tx():
> > > >
> > > > [ 78.114630] Unable to handle kernel NULL pointer dereference
> > > > at virtual address
> > > > [ 78.123778] Mem abort info:
> > > > [ 78.126560] ESR = 0x8607
> > > > [ 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=0027d41a8600
> > > > [ 78.147562] [] pgd=0027893f0003,
> > > > p4d=0027893f0003, pud=0027893f0003,
> > > > pmd=0027c9a20003, pte=
> > > > [ 78.160029] Internal error: Oops: 8607 [#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 : 800062eefb80
> > > > [ 78.238517] x29: 800062eefb80 x28: 0fff
> > > > [ 78.243807] x27: 800062eefd80 x26: 202fd83b3000
> > > > [ 78.249098] x25: 800062eefd80 x24: 202fd83b3000
> > > > [ 78.254388] x23: 002fc5e50be8 x22: 0002
> > > > [ 78.259679] x21: 0001 x20:
> > > > [ 78.264969] x19: a688827eecc8 x18:
> > > > [ 78.270259] x17: x16:
> > > > [ 78.275550] x15: a68881bc67a8 x14: 02e6
> > > > [ 78.280841] x13: a68881bc67a8 x12: c539
> > > > [ 78.286131] x11: d37a6f4de9bd37a7 x10: a68881cccff0
> > > > [ 78.291421] x9 : a68881bc6000 x8 : a688819daa88
> > > > [ 78.296711] x7 : a688822a0f20 x6 : a688819e
> > > > [ 78.302002] x5 : 800062eef9d0 x4 : a68881e707a8
> > > > [ 78.307292] x3 : x2 : 0002
> > > > [ 78.312582] x1 : 0001 x0 : a688827eecc8
> > > > [ 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
> > > > ---
> > > > 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
> > #include
> > #include
> > #include
> > #include
> > #include
> > #include
> > #include
> >
> > #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] = {0x};
> >
> > int main(void)
> > {
> >
Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
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 +, Yang Yingliang wrote:
I got null-ptr-deref in serial8250_start_tx():
[ 78.114630] Unable to handle kernel NULL pointer dereference at
virtual address
[ 78.123778] Mem abort info:
[ 78.126560] ESR = 0x8607
[ 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=0027d41a8600
[ 78.147562] [] pgd=0027893f0003,
p4d=0027893f0003, pud=0027893f0003, pmd=0027c9a20003,
pte=
[ 78.160029] Internal error: Oops: 8607 [#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 : 800062eefb80
[ 78.238517] x29: 800062eefb80 x28: 0fff
[ 78.243807] x27: 800062eefd80 x26: 202fd83b3000
[ 78.249098] x25: 800062eefd80 x24: 202fd83b3000
[ 78.254388] x23: 002fc5e50be8 x22: 0002
[ 78.259679] x21: 0001 x20:
[ 78.264969] x19: a688827eecc8 x18:
[ 78.270259] x17: x16:
[ 78.275550] x15: a68881bc67a8 x14: 02e6
[ 78.280841] x13: a68881bc67a8 x12: c539
[ 78.286131] x11: d37a6f4de9bd37a7 x10: a68881cccff0
[ 78.291421] x9 : a68881bc6000 x8 : a688819daa88
[ 78.296711] x7 : a688822a0f20 x6 : a688819e
[ 78.302002] x5 : 800062eef9d0 x4 : a68881e707a8
[ 78.307292] x3 : x2 : 0002
[ 78.312582] x1 : 0001 x0 : a688827eecc8
[ 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
---
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
#include
#include
#include
#include
#include
#include
#include
#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] = {0x};
int main(void)
{
syscall(__NR_mmap, 0x2000ul, 0x100ul, 3ul, 0x32ul, -1, 0);
intptr_t res = 0;
memcpy((void*)0x2040, "/dev/ttyS3\000", 11);
res = syscall(__NR_openat, 0xff9cul, 0x2040ul,
0x401ul, 0ul);
if (res != -1)
r[0] = res;
syscall(__NR_ioctl, r[0], 0x5412ul, 0x2080ul);
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
[ 49.432786] PGD 8003d7573067 P4D 8003d7573067 PUD 3d7526067 PMD 0
[ 49.436944] Oops: 0010 [#1] SMP KASAN PTI
[ 49.439490] CPU: 1 PID: 2491 Comm: test Not tainted
Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
On 2020/7/21 18:48, Greg KH wrote:
On Tue, Jul 21, 2020 at 02:38:52PM +, Yang Yingliang wrote:
I got null-ptr-deref in serial8250_start_tx():
[ 78.114630] Unable to handle kernel NULL pointer dereference at virtual
address
[ 78.123778] Mem abort info:
[ 78.126560] ESR = 0x8607
[ 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=0027d41a8600
[ 78.147562] [] pgd=0027893f0003, p4d=0027893f0003,
pud=0027893f0003, pmd=0027c9a20003, pte=
[ 78.160029] Internal error: Oops: 8607 [#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 : 800062eefb80
[ 78.238517] x29: 800062eefb80 x28: 0fff
[ 78.243807] x27: 800062eefd80 x26: 202fd83b3000
[ 78.249098] x25: 800062eefd80 x24: 202fd83b3000
[ 78.254388] x23: 002fc5e50be8 x22: 0002
[ 78.259679] x21: 0001 x20:
[ 78.264969] x19: a688827eecc8 x18:
[ 78.270259] x17: x16:
[ 78.275550] x15: a68881bc67a8 x14: 02e6
[ 78.280841] x13: a68881bc67a8 x12: c539
[ 78.286131] x11: d37a6f4de9bd37a7 x10: a68881cccff0
[ 78.291421] x9 : a68881bc6000 x8 : a688819daa88
[ 78.296711] x7 : a688822a0f20 x6 : a688819e
[ 78.302002] x5 : 800062eef9d0 x4 : a68881e707a8
[ 78.307292] x3 : x2 : 0002
[ 78.312582] x1 : 0001 x0 : a688827eecc8
[ 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
---
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
#include
#include
#include
#include
#include
#include
#include
#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] = {0x};
int main(void)
{
syscall(__NR_mmap, 0x2000ul, 0x100ul, 3ul, 0x32ul, -1, 0);
intptr_t res = 0;
memcpy((void*)0x2040, "/dev/ttyS3\000", 11);
res = syscall(__NR_openat, 0xff9cul, 0x2040ul,
0x401ul, 0ul);
if (res != -1)
r[0] = res;
syscall(__NR_ioctl, r[0], 0x5412ul, 0x2080ul);
return 0;
}
Thanks,
Yang
thanks,
greg k-h
.
Re: [PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
On Tue, Jul 21, 2020 at 02:38:52PM +, Yang Yingliang wrote: > I got null-ptr-deref in serial8250_start_tx(): > > [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual > address > [ 78.123778] Mem abort info: > [ 78.126560] ESR = 0x8607 > [ 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=0027d41a8600 > [ 78.147562] [] pgd=0027893f0003, p4d=0027893f0003, > pud=0027893f0003, pmd=0027c9a20003, pte= > [ 78.160029] Internal error: Oops: 8607 [#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 : 800062eefb80 > [ 78.238517] x29: 800062eefb80 x28: 0fff > [ 78.243807] x27: 800062eefd80 x26: 202fd83b3000 > [ 78.249098] x25: 800062eefd80 x24: 202fd83b3000 > [ 78.254388] x23: 002fc5e50be8 x22: 0002 > [ 78.259679] x21: 0001 x20: > [ 78.264969] x19: a688827eecc8 x18: > [ 78.270259] x17: x16: > [ 78.275550] x15: a68881bc67a8 x14: 02e6 > [ 78.280841] x13: a68881bc67a8 x12: c539 > [ 78.286131] x11: d37a6f4de9bd37a7 x10: a68881cccff0 > [ 78.291421] x9 : a68881bc6000 x8 : a688819daa88 > [ 78.296711] x7 : a688822a0f20 x6 : a688819e > [ 78.302002] x5 : 800062eef9d0 x4 : a68881e707a8 > [ 78.307292] x3 : x2 : 0002 > [ 78.312582] x1 : 0001 x0 : a688827eecc8 > [ 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 > --- > 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
[PATCH] serial: 8250: fix null-ptr-deref in serial8250_start_tx()
I got null-ptr-deref in serial8250_start_tx(): [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address [ 78.123778] Mem abort info: [ 78.126560] ESR = 0x8607 [ 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=0027d41a8600 [ 78.147562] [] pgd=0027893f0003, p4d=0027893f0003, pud=0027893f0003, pmd=0027c9a20003, pte= [ 78.160029] Internal error: Oops: 8607 [#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 : 800062eefb80 [ 78.238517] x29: 800062eefb80 x28: 0fff [ 78.243807] x27: 800062eefd80 x26: 202fd83b3000 [ 78.249098] x25: 800062eefd80 x24: 202fd83b3000 [ 78.254388] x23: 002fc5e50be8 x22: 0002 [ 78.259679] x21: 0001 x20: [ 78.264969] x19: a688827eecc8 x18: [ 78.270259] x17: x16: [ 78.275550] x15: a68881bc67a8 x14: 02e6 [ 78.280841] x13: a68881bc67a8 x12: c539 [ 78.286131] x11: d37a6f4de9bd37a7 x10: a68881cccff0 [ 78.291421] x9 : a68881bc6000 x8 : a688819daa88 [ 78.296711] x7 : a688822a0f20 x6 : a688819e [ 78.302002] x5 : 800062eef9d0 x4 : a68881e707a8 [ 78.307292] x3 : x2 : 0002 [ 78.312582] x1 : 0001 x0 : a688827eecc8 [ 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 --- 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
