Re: [PATCH] proc_sysclt: fix oops caused by incorrect command parameters.

2021-01-07 Thread Kees Cook 
On Thu, Jan 07, 2021 at 02:14:18PM +0800, Xiaoming Ni wrote:
> On 2021/1/7 7:46, Kees Cook wrote:
> > subject typo: "sysclt" -> "sysctl"
> > 
> > On Thu, Dec 24, 2020 at 03:42:56PM +0800, Xiaoming Ni wrote:
> > > [...]
> > > + if (!val)
> > > + return 0;
> > > +
> > >   if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
> > >   param += sizeof("sysctl") - 1;
> > 
> > Otherwise, yeah, this is a good test to add. I would make it more
> > verbose, though:
> > 
> > if (!val) {
> > pr_err("Missing param value! Expected '%s=...value...'\n", 
> > param);
> > return 0;
> > }
> > 
> Yes, it's better to add log output.
> Thank you for your review.
> Do I need to send V2 patch based on review comments?

Yes please. :)

-- 
Kees Cook

Re: [PATCH] proc_sysclt: fix oops caused by incorrect command parameters.

2021-01-06 Thread Xiaoming Ni 

On 2021/1/7 7:46, Kees Cook wrote:

subject typo: "sysclt" -> "sysctl"

On Thu, Dec 24, 2020 at 03:42:56PM +0800, Xiaoming Ni wrote:

The process_sysctl_arg() does not check whether val is empty before
  invoking strlen(val). If the command line parameter () is incorrectly
  configured and val is empty, oops is triggered.

For example, "hung_task_panic=1" is incorrectly written as "hung_task_panic".

log:
Kernel command line:  hung_task_panic

[000n] user address but active_mm is swapper
Internal error: Oops: 9605 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.1 #1
Hardware name: linux,dummy-virt (DT)
pstate: 4005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
pc : __pi_strlen+0x10/0x98
lr : process_sysctl_arg+0x1e4/0x2ac
sp : ffc01104bd40
x29: ffc01104bd40 x28: 
x27: ff80c0a4691e x26: ffc0102a7c8c
x25:  x24: ffc01104be80
x23: ff80c22f0b00 x22: ff80c02e28c0
x21: ffc0109f9000 x20: 
x19: ffc0107c08de x18: 0003
x17: ffc01105d000 x16: 0054
x15:  x14: 3030253078413830
x13:  x12: 
x11: 0101010101010101 x10: 0005
x9 : 0003 x8 : ff80c0980c08
x7 :  x6 : 0002
x5 : ff80c0235000 x4 : ff810f7c7ee0
x3 : 043a x2 : 00bdcc4ebacf1a54
x1 :  x0 : 
Call trace:
 __pi_strlen+0x10/0x98
 parse_args+0x278/0x344
 do_sysctl_args+0x8c/0xfc
 kernel_init+0x5c/0xf4
 ret_from_fork+0x10/0x30
Code: b200c3eb 927cec01 f2400c07 54000301 (a8c10c22)

Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters
  from kernel command line")
Signed-off-by: Xiaoming Ni 
---
  fs/proc/proc_sysctl.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 317899222d7f..4516411a2b44 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1757,6 +1757,9 @@ static int process_sysctl_arg(char *param, char *val,
loff_t pos = 0;
ssize_t wret;
  
+	if (!val)

+   return 0;
+
if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
param += sizeof("sysctl") - 1;


Otherwise, yeah, this is a good test to add. I would make it more
verbose, though:

if (!val) {
pr_err("Missing param value! Expected '%s=...value...'\n", 
param);
return 0;
}


Yes, it's better to add log output.
Thank you for your review.
Do I need to send V2 patch based on review comments?

Thanks
Xiaoming Ni

Re: [PATCH] proc_sysclt: fix oops caused by incorrect command parameters.

2021-01-06 Thread Kees Cook 
subject typo: "sysclt" -> "sysctl"

On Thu, Dec 24, 2020 at 03:42:56PM +0800, Xiaoming Ni wrote:
> The process_sysctl_arg() does not check whether val is empty before
>  invoking strlen(val). If the command line parameter () is incorrectly
>  configured and val is empty, oops is triggered.
> 
> For example, "hung_task_panic=1" is incorrectly written as "hung_task_panic".
> 
> log:
>   Kernel command line:  hung_task_panic
>   
>   [000n] user address but active_mm is swapper
>   Internal error: Oops: 9605 [#1] SMP
>   Modules linked in:
>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.1 #1
>   Hardware name: linux,dummy-virt (DT)
>   pstate: 4005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
>   pc : __pi_strlen+0x10/0x98
>   lr : process_sysctl_arg+0x1e4/0x2ac
>   sp : ffc01104bd40
>   x29: ffc01104bd40 x28: 
>   x27: ff80c0a4691e x26: ffc0102a7c8c
>   x25:  x24: ffc01104be80
>   x23: ff80c22f0b00 x22: ff80c02e28c0
>   x21: ffc0109f9000 x20: 
>   x19: ffc0107c08de x18: 0003
>   x17: ffc01105d000 x16: 0054
>   x15:  x14: 3030253078413830
>   x13:  x12: 
>   x11: 0101010101010101 x10: 0005
>   x9 : 0003 x8 : ff80c0980c08
>   x7 :  x6 : 0002
>   x5 : ff80c0235000 x4 : ff810f7c7ee0
>   x3 : 043a x2 : 00bdcc4ebacf1a54
>   x1 :  x0 : 
>   Call trace:
>__pi_strlen+0x10/0x98
>parse_args+0x278/0x344
>do_sysctl_args+0x8c/0xfc
>kernel_init+0x5c/0xf4
>ret_from_fork+0x10/0x30
>   Code: b200c3eb 927cec01 f2400c07 54000301 (a8c10c22)
> 
> Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters
>  from kernel command line")
> Signed-off-by: Xiaoming Ni 
> ---
>  fs/proc/proc_sysctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index 317899222d7f..4516411a2b44 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -1757,6 +1757,9 @@ static int process_sysctl_arg(char *param, char *val,
>   loff_t pos = 0;
>   ssize_t wret;
>  
> + if (!val)
> + return 0;
> +
>   if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
>   param += sizeof("sysctl") - 1;

Otherwise, yeah, this is a good test to add. I would make it more
verbose, though:

if (!val) {
pr_err("Missing param value! Expected '%s=...value...'\n", 
param);
return 0;
}

-- 
Kees Cook

ping //Re: [PATCH] proc_sysclt: fix oops caused by incorrect command parameters.

2021-01-03 Thread Xiaoming Ni 

ping


On 2020/12/24 15:42, Xiaoming Ni wrote:

The process_sysctl_arg() does not check whether val is empty before
  invoking strlen(val). If the command line parameter () is incorrectly
  configured and val is empty, oops is triggered.

For example, "hung_task_panic=1" is incorrectly written as "hung_task_panic".

log:
Kernel command line:  hung_task_panic

[000n] user address but active_mm is swapper
Internal error: Oops: 9605 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.1 #1
Hardware name: linux,dummy-virt (DT)
pstate: 4005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
pc : __pi_strlen+0x10/0x98
lr : process_sysctl_arg+0x1e4/0x2ac
sp : ffc01104bd40
x29: ffc01104bd40 x28: 
x27: ff80c0a4691e x26: ffc0102a7c8c
x25:  x24: ffc01104be80
x23: ff80c22f0b00 x22: ff80c02e28c0
x21: ffc0109f9000 x20: 
x19: ffc0107c08de x18: 0003
x17: ffc01105d000 x16: 0054
x15:  x14: 3030253078413830
x13:  x12: 
x11: 0101010101010101 x10: 0005
x9 : 0003 x8 : ff80c0980c08
x7 :  x6 : 0002
x5 : ff80c0235000 x4 : ff810f7c7ee0
x3 : 043a x2 : 00bdcc4ebacf1a54
x1 :  x0 : 
Call trace:
 __pi_strlen+0x10/0x98
 parse_args+0x278/0x344
 do_sysctl_args+0x8c/0xfc
 kernel_init+0x5c/0xf4
 ret_from_fork+0x10/0x30
Code: b200c3eb 927cec01 f2400c07 54000301 (a8c10c22)

Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters
  from kernel command line")
Signed-off-by: Xiaoming Ni 
---
  fs/proc/proc_sysctl.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 317899222d7f..4516411a2b44 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1757,6 +1757,9 @@ static int process_sysctl_arg(char *param, char *val,
loff_t pos = 0;
ssize_t wret;
  
+	if (!val)

+   return 0;
+
if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
param += sizeof("sysctl") - 1;

[PATCH] proc_sysclt: fix oops caused by incorrect command parameters.

2020-12-23 Thread Xiaoming Ni 
The process_sysctl_arg() does not check whether val is empty before
 invoking strlen(val). If the command line parameter () is incorrectly
 configured and val is empty, oops is triggered.

For example, "hung_task_panic=1" is incorrectly written as "hung_task_panic".

log:
Kernel command line:  hung_task_panic

[000n] user address but active_mm is swapper
Internal error: Oops: 9605 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.1 #1
Hardware name: linux,dummy-virt (DT)
pstate: 4005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
pc : __pi_strlen+0x10/0x98
lr : process_sysctl_arg+0x1e4/0x2ac
sp : ffc01104bd40
x29: ffc01104bd40 x28: 
x27: ff80c0a4691e x26: ffc0102a7c8c
x25:  x24: ffc01104be80
x23: ff80c22f0b00 x22: ff80c02e28c0
x21: ffc0109f9000 x20: 
x19: ffc0107c08de x18: 0003
x17: ffc01105d000 x16: 0054
x15:  x14: 3030253078413830
x13:  x12: 
x11: 0101010101010101 x10: 0005
x9 : 0003 x8 : ff80c0980c08
x7 :  x6 : 0002
x5 : ff80c0235000 x4 : ff810f7c7ee0
x3 : 043a x2 : 00bdcc4ebacf1a54
x1 :  x0 : 
Call trace:
 __pi_strlen+0x10/0x98
 parse_args+0x278/0x344
 do_sysctl_args+0x8c/0xfc
 kernel_init+0x5c/0xf4
 ret_from_fork+0x10/0x30
Code: b200c3eb 927cec01 f2400c07 54000301 (a8c10c22)

Fixes: 3db978d480e2843 ("kernel/sysctl: support setting sysctl parameters
 from kernel command line")
Signed-off-by: Xiaoming Ni 
---
 fs/proc/proc_sysctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 317899222d7f..4516411a2b44 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1757,6 +1757,9 @@ static int process_sysctl_arg(char *param, char *val,
loff_t pos = 0;
ssize_t wret;
 
+   if (!val)
+   return 0;
+
if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
param += sizeof("sysctl") - 1;
 
-- 
2.27.0