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]>
Reviewed-by: Daniel Thompson <[email protected]>
---
v2:
- Split out printk cleanups
- Add cc to [email protected]
v3:
- Use more meaningful error message
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..f4d0ef6 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: config string not provided\n");
+ 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.
Signed-off-by: He Zhe <[email protected]>
---
v2:
- Split printk cleanups into a single patch
- Add cc to [email protected]
v3:
- Add pr_fmt for mod name
drivers/tty/serial/kgdboc.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index f4d0ef6..371357d 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -8,6 +8,9 @@
*
* 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/kgdb.h>
@@ -131,12 +134,12 @@ static void kgdboc_unregister_kbd(void)
static int kgdboc_option_setup(char *opt)
{
if (!opt) {
- pr_err("kgdboc: config string not provided\n");
+ pr_err("config string not provided\n");
return -EINVAL;
}
if (strlen(opt) >= MAX_CONFIG_LEN) {
- printk(KERN_ERR "kgdboc: config string too long\n");
+ pr_err("config string too long\n");
return -ENOSPC;
}
strcpy(config, opt);
@@ -253,7 +256,7 @@ 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("config string too long\n");
return -ENOSPC;
}
@@ -264,8 +267,7 @@ 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("Cannot reconfigure while KGDB is connected.\n");
return -EBUSY;
}
--
2.7.4
On Tue, Aug 14, 2018 at 10:57:40PM +0800, [email protected] wrote:
> From: He Zhe <[email protected]>
>
> pr_* is preferred according to scripts/checkpatch.pl.
>
> Signed-off-by: He Zhe <[email protected]>
I thought I'd already done this but it looks like maybe I didn't get
round to it...
Acked-by: Daniel Thompson <[email protected]>
> ---
> v2:
> - Split printk cleanups into a single patch
> - Add cc to [email protected]
> v3:
> - Add pr_fmt for mod name
>
> drivers/tty/serial/kgdboc.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
> index f4d0ef6..371357d 100644
> --- a/drivers/tty/serial/kgdboc.c
> +++ b/drivers/tty/serial/kgdboc.c
> @@ -8,6 +8,9 @@
> *
> * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
> */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> #include <linux/kernel.h>
> #include <linux/ctype.h>
> #include <linux/kgdb.h>
> @@ -131,12 +134,12 @@ static void kgdboc_unregister_kbd(void)
> static int kgdboc_option_setup(char *opt)
> {
> if (!opt) {
> - pr_err("kgdboc: config string not provided\n");
> + pr_err("config string not provided\n");
> return -EINVAL;
> }
>
> if (strlen(opt) >= MAX_CONFIG_LEN) {
> - printk(KERN_ERR "kgdboc: config string too long\n");
> + pr_err("config string too long\n");
> return -ENOSPC;
> }
> strcpy(config, opt);
> @@ -253,7 +256,7 @@ 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("config string too long\n");
> return -ENOSPC;
> }
>
> @@ -264,8 +267,7 @@ 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("Cannot reconfigure while KGDB is connected.\n");
>
> return -EBUSY;
> }
> --
> 2.7.4
>