From: He Zhe <[email protected]>
kgdboc_option_setup does not check input argument before passing it
to strlen. The argument would be a NULL pointer if "ekgdboc", without
its value, is set in command line and thus cause the following panic.
PANIC: early exception 0xe3 IP 10:ffffffff8fbbb620 error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #1
[ 0.000000] RIP: 0010:strlen+0x0/0x20
...
[ 0.000000] Call Trace
[ 0.000000] ? kgdboc_option_setup+0x9/0xa0
[ 0.000000] ? kgdboc_early_init+0x6/0x1b
[ 0.000000] ? do_early_param+0x4d/0x82
[ 0.000000] ? parse_args+0x212/0x330
[ 0.000000] ? rdinit_setup+0x26/0x26
[ 0.000000] ? parse_early_options+0x20/0x23
[ 0.000000] ? rdinit_setup+0x26/0x26
[ 0.000000] ? parse_early_param+0x2d/0x39
[ 0.000000] ? setup_arch+0x2f7/0xbf4
[ 0.000000] ? start_kernel+0x5e/0x4c2
[ 0.000000] ? load_ucode_bsp+0x113/0x12f
[ 0.000000] ? secondary_startup_64+0xa5/0xb0
This patch adds a check to prevent the panic.
Cc: [email protected]
Signed-off-by: He Zhe <[email protected]>
---
v2:
- Split out printk cleanups
- Add cc to [email protected]
drivers/tty/serial/kgdboc.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index b4ba2b1..206f8c2 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -130,6 +130,11 @@ static void kgdboc_unregister_kbd(void)
static int kgdboc_option_setup(char *opt)
{
+ if (!opt) {
+ pr_err("kgdboc: null option\n");
+ return -EINVAL;
+ }
+
if (strlen(opt) >= MAX_CONFIG_LEN) {
printk(KERN_ERR "kgdboc: config string too long\n");
return -ENOSPC;
--
2.7.4
On Tue, Aug 14, 2018 at 08:46:00PM +0800, [email protected] wrote:
> From: He Zhe <[email protected]>
>
> kgdboc_option_setup does not check input argument before passing it
> to strlen. The argument would be a NULL pointer if "ekgdboc", without
> its value, is set in command line and thus cause the following panic.
>
> PANIC: early exception 0xe3 IP 10:ffffffff8fbbb620 error 0 cr2 0x0
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #1
> [ 0.000000] RIP: 0010:strlen+0x0/0x20
> ...
> [ 0.000000] Call Trace
> [ 0.000000] ? kgdboc_option_setup+0x9/0xa0
> [ 0.000000] ? kgdboc_early_init+0x6/0x1b
> [ 0.000000] ? do_early_param+0x4d/0x82
> [ 0.000000] ? parse_args+0x212/0x330
> [ 0.000000] ? rdinit_setup+0x26/0x26
> [ 0.000000] ? parse_early_options+0x20/0x23
> [ 0.000000] ? rdinit_setup+0x26/0x26
> [ 0.000000] ? parse_early_param+0x2d/0x39
> [ 0.000000] ? setup_arch+0x2f7/0xbf4
> [ 0.000000] ? start_kernel+0x5e/0x4c2
> [ 0.000000] ? load_ucode_bsp+0x113/0x12f
> [ 0.000000] ? secondary_startup_64+0xa5/0xb0
>
> This patch adds a check to prevent the panic.
>
> Cc: [email protected]
> Signed-off-by: He Zhe <[email protected]>
> ---
> v2:
> - Split out printk cleanups
> - Add cc to [email protected]
>
> drivers/tty/serial/kgdboc.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
> index b4ba2b1..206f8c2 100644
> --- a/drivers/tty/serial/kgdboc.c
> +++ b/drivers/tty/serial/kgdboc.c
> @@ -130,6 +130,11 @@ static void kgdboc_unregister_kbd(void)
>
> static int kgdboc_option_setup(char *opt)
> {
> + if (!opt) {
> + pr_err("kgdboc: null option\n");
Apologies... I should have picked this up when I replied earlier but
this error message describes what the function gets when I think it
should report what the user actually did. So should be something like:
pr_err("kgdboc: config string not provided\n");
With that (or a very similar) change:
Reviewed-by: Daniel Thompson <[email protected]>
Daniel.
> + return -EINVAL;
> + }
> +
> if (strlen(opt) >= MAX_CONFIG_LEN) {
> printk(KERN_ERR "kgdboc: config string too long\n");
> return -ENOSPC;
> --
> 2.7.4
>
From: He Zhe <[email protected]>
pr_* is preferred according to scripts/checkpatch.pl.
Cc: [email protected]
Signed-off-by: He Zhe <[email protected]>
---
v2:
- Split printk cleanups into a single patch
- Add cc to [email protected]
drivers/tty/serial/kgdboc.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index 206f8c2..0003d6c 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -136,7 +136,7 @@ static int kgdboc_option_setup(char *opt)
}
if (strlen(opt) >= MAX_CONFIG_LEN) {
- printk(KERN_ERR "kgdboc: config string too long\n");
+ pr_err("kgdboc: config string too long\n");
return -ENOSPC;
}
strcpy(config, opt);
@@ -253,7 +253,7 @@ static int param_set_kgdboc_var(const char *kmessage,
int len = strlen(kmessage);
if (len >= MAX_CONFIG_LEN) {
- printk(KERN_ERR "kgdboc: config string too long\n");
+ pr_err("kgdboc: config string too long\n");
return -ENOSPC;
}
@@ -264,8 +264,7 @@ static int param_set_kgdboc_var(const char *kmessage,
}
if (kgdb_connected) {
- printk(KERN_ERR
- "kgdboc: Cannot reconfigure while KGDB is connected.\n");
+ pr_err("kgdboc: Cannot reconfigure while KGDB is connected.\n");
return -EBUSY;
}
--
2.7.4
On Tue, Aug 14, 2018 at 08:46:01PM +0800, [email protected] wrote:
> From: He Zhe <[email protected]>
>
> pr_* is preferred according to scripts/checkpatch.pl.
>
> Cc: [email protected]
This change does not "fix a problem that causes a build error
(but not for things marked CONFIG_BROKEN), an oops, a hang, data
corruption, a real security issue, or some “oh, that’s not good” issue.
In short, something critical.". Only the first patch meets this criteria
and only that patch should be Cc:ed to stable@ .
Please remove from this patch.
> Signed-off-by: He Zhe <[email protected]>
> ---
> v2:
> - Split printk cleanups into a single patch
> - Add cc to [email protected]
>
> drivers/tty/serial/kgdboc.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
> index 206f8c2..0003d6c 100644
> --- a/drivers/tty/serial/kgdboc.c
> +++ b/drivers/tty/serial/kgdboc.c
> @@ -136,7 +136,7 @@ static int kgdboc_option_setup(char *opt)
> }
>
> if (strlen(opt) >= MAX_CONFIG_LEN) {
> - printk(KERN_ERR "kgdboc: config string too long\n");
> + pr_err("kgdboc: config string too long\n");
Looks like you should remove the tags from pr_err and use pr_fmt(fmt) to
put tags on the messages:
#define pr_fmt(fmt) "kgdboc: " fmt
Daniel.
> return -ENOSPC;
> }
> strcpy(config, opt);
> @@ -253,7 +253,7 @@ static int param_set_kgdboc_var(const char *kmessage,
> int len = strlen(kmessage);
>
> if (len >= MAX_CONFIG_LEN) {
> - printk(KERN_ERR "kgdboc: config string too long\n");
> + pr_err("kgdboc: config string too long\n");
> return -ENOSPC;
> }
>
> @@ -264,8 +264,7 @@ static int param_set_kgdboc_var(const char *kmessage,
> }
>
> if (kgdb_connected) {
> - printk(KERN_ERR
> - "kgdboc: Cannot reconfigure while KGDB is connected.\n");
> + pr_err("kgdboc: Cannot reconfigure while KGDB is connected.\n");
>
> return -EBUSY;
> }
> --
> 2.7.4
>
On Tue, 2018-08-14 at 14:35 +0100, Daniel Thompson wrote:
> On Tue, Aug 14, 2018 at 08:46:01PM +0800, [email protected] wrote:
> > From: He Zhe <[email protected]>
> >
> > pr_* is preferred according to scripts/checkpatch.pl.
[]
> > diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
[]
> > @@ -136,7 +136,7 @@ static int kgdboc_option_setup(char *opt)
> > }
> >
> > if (strlen(opt) >= MAX_CONFIG_LEN) {
> > - printk(KERN_ERR "kgdboc: config string too long\n");
> > + pr_err("kgdboc: config string too long\n");
>
> Looks like you should remove the tags from pr_err and use pr_fmt(fmt) to
> put tags on the messages:
>
> #define pr_fmt(fmt) "kgdboc: " fmt
True and it's probably better to use:
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
On Tue, Aug 14, 2018 at 07:04:11AM -0700, Joe Perches wrote:
> On Tue, 2018-08-14 at 14:35 +0100, Daniel Thompson wrote:
> > On Tue, Aug 14, 2018 at 08:46:01PM +0800, [email protected] wrote:
> > > From: He Zhe <[email protected]>
> > >
> > > pr_* is preferred according to scripts/checkpatch.pl.
> []
> > > diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
> []
> > > @@ -136,7 +136,7 @@ static int kgdboc_option_setup(char *opt)
> > > }
> > >
> > > if (strlen(opt) >= MAX_CONFIG_LEN) {
> > > - printk(KERN_ERR "kgdboc: config string too long\n");
> > > + pr_err("kgdboc: config string too long\n");
> >
> > Looks like you should remove the tags from pr_err and use pr_fmt(fmt) to
> > put tags on the messages:
> >
> > #define pr_fmt(fmt) "kgdboc: " fmt
>
> True and it's probably better to use:
>
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Good point! Thanks.
Daniel.
On 2018年08月14日 22:41, Daniel Thompson wrote:
> On Tue, Aug 14, 2018 at 07:04:11AM -0700, Joe Perches wrote:
>> On Tue, 2018-08-14 at 14:35 +0100, Daniel Thompson wrote:
>>> On Tue, Aug 14, 2018 at 08:46:01PM +0800, [email protected] wrote:
>>>> From: He Zhe <[email protected]>
>>>>
>>>> pr_* is preferred according to scripts/checkpatch.pl.
>> []
>>>> diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
>> []
>>>> @@ -136,7 +136,7 @@ static int kgdboc_option_setup(char *opt)
>>>> }
>>>>
>>>> if (strlen(opt) >= MAX_CONFIG_LEN) {
>>>> - printk(KERN_ERR "kgdboc: config string too long\n");
>>>> + pr_err("kgdboc: config string too long\n");
>>> Looks like you should remove the tags from pr_err and use pr_fmt(fmt) to
>>> put tags on the messages:
>>>
>>> #define pr_fmt(fmt) "kgdboc: " fmt
>> True and it's probably better to use:
>>
>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> Good point! Thanks.
Daniel, Joe, thanks for your good suggestions. v3 is sent.
Zhe
>
>
> Daniel.
>