| Message ID | 20201224074256.117413-1-nixiaoming@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | proc_sysclt: fix oops caused by incorrect command parameters. | expand |
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 > .... > [000000000000000n] user address but active_mm is swapper > Internal error: Oops: 96000005 [#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: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) > pc : __pi_strlen+0x10/0x98 > lr : process_sysctl_arg+0x1e4/0x2ac > sp : ffffffc01104bd40 > x29: ffffffc01104bd40 x28: 0000000000000000 > x27: ffffff80c0a4691e x26: ffffffc0102a7c8c > x25: 0000000000000000 x24: ffffffc01104be80 > x23: ffffff80c22f0b00 x22: ffffff80c02e28c0 > x21: ffffffc0109f9000 x20: 0000000000000000 > x19: ffffffc0107c08de x18: 0000000000000003 > x17: ffffffc01105d000 x16: 0000000000000054 > x15: ffffffffffffffff x14: 3030253078413830 > x13: 000000000000ffff x12: 0000000000000000 > x11: 0101010101010101 x10: 0000000000000005 > x9 : 0000000000000003 x8 : ffffff80c0980c08 > x7 : 0000000000000000 x6 : 0000000000000002 > x5 : ffffff80c0235000 x4 : ffffff810f7c7ee0 > x3 : 000000000000043a x2 : 00bdcc4ebacf1a54 > x1 : 0000000000000000 x0 : 0000000000000000 > 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 <nixiaoming@huawei.com> > --- > 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; > >
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 > .... > [000000000000000n] user address but active_mm is swapper > Internal error: Oops: 96000005 [#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: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) > pc : __pi_strlen+0x10/0x98 > lr : process_sysctl_arg+0x1e4/0x2ac > sp : ffffffc01104bd40 > x29: ffffffc01104bd40 x28: 0000000000000000 > x27: ffffff80c0a4691e x26: ffffffc0102a7c8c > x25: 0000000000000000 x24: ffffffc01104be80 > x23: ffffff80c22f0b00 x22: ffffff80c02e28c0 > x21: ffffffc0109f9000 x20: 0000000000000000 > x19: ffffffc0107c08de x18: 0000000000000003 > x17: ffffffc01105d000 x16: 0000000000000054 > x15: ffffffffffffffff x14: 3030253078413830 > x13: 000000000000ffff x12: 0000000000000000 > x11: 0101010101010101 x10: 0000000000000005 > x9 : 0000000000000003 x8 : ffffff80c0980c08 > x7 : 0000000000000000 x6 : 0000000000000002 > x5 : ffffff80c0235000 x4 : ffffff810f7c7ee0 > x3 : 000000000000043a x2 : 00bdcc4ebacf1a54 > x1 : 0000000000000000 x0 : 0000000000000000 > 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 <nixiaoming@huawei.com> > --- > 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; }
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 >> .... >> [000000000000000n] user address but active_mm is swapper >> Internal error: Oops: 96000005 [#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: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) >> pc : __pi_strlen+0x10/0x98 >> lr : process_sysctl_arg+0x1e4/0x2ac >> sp : ffffffc01104bd40 >> x29: ffffffc01104bd40 x28: 0000000000000000 >> x27: ffffff80c0a4691e x26: ffffffc0102a7c8c >> x25: 0000000000000000 x24: ffffffc01104be80 >> x23: ffffff80c22f0b00 x22: ffffff80c02e28c0 >> x21: ffffffc0109f9000 x20: 0000000000000000 >> x19: ffffffc0107c08de x18: 0000000000000003 >> x17: ffffffc01105d000 x16: 0000000000000054 >> x15: ffffffffffffffff x14: 3030253078413830 >> x13: 000000000000ffff x12: 0000000000000000 >> x11: 0101010101010101 x10: 0000000000000005 >> x9 : 0000000000000003 x8 : ffffff80c0980c08 >> x7 : 0000000000000000 x6 : 0000000000000002 >> x5 : ffffff80c0235000 x4 : ffffff810f7c7ee0 >> x3 : 000000000000043a x2 : 00bdcc4ebacf1a54 >> x1 : 0000000000000000 x0 : 0000000000000000 >> 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 <nixiaoming@huawei.com> >> --- >> 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
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. :)
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;
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 .... [000000000000000n] user address but active_mm is swapper Internal error: Oops: 96000005 [#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: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) pc : __pi_strlen+0x10/0x98 lr : process_sysctl_arg+0x1e4/0x2ac sp : ffffffc01104bd40 x29: ffffffc01104bd40 x28: 0000000000000000 x27: ffffff80c0a4691e x26: ffffffc0102a7c8c x25: 0000000000000000 x24: ffffffc01104be80 x23: ffffff80c22f0b00 x22: ffffff80c02e28c0 x21: ffffffc0109f9000 x20: 0000000000000000 x19: ffffffc0107c08de x18: 0000000000000003 x17: ffffffc01105d000 x16: 0000000000000054 x15: ffffffffffffffff x14: 3030253078413830 x13: 000000000000ffff x12: 0000000000000000 x11: 0101010101010101 x10: 0000000000000005 x9 : 0000000000000003 x8 : ffffff80c0980c08 x7 : 0000000000000000 x6 : 0000000000000002 x5 : ffffff80c0235000 x4 : ffffff810f7c7ee0 x3 : 000000000000043a x2 : 00bdcc4ebacf1a54 x1 : 0000000000000000 x0 : 0000000000000000 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 <nixiaoming@huawei.com> --- fs/proc/proc_sysctl.c | 3 +++ 1 file changed, 3 insertions(+)