* [PATCH] tty: xtensa/iss: use strnlen to improve iss_console_write
@ 2026-04-30 9:02 Thorsten Blum
2026-04-30 9:45 ` Max Filippov
0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2026-04-30 9:02 UTC (permalink / raw)
To: Chris Zankel, Max Filippov; +Cc: Thorsten Blum, linux-kernel
Use strnlen() to limit scanning 's' to 'count' bytes. Use the length of
's' to decide if simc_write() should be called instead of dereferencing
it first and then calling strlen().
With strnlen(), iss_console_write() is further hardened against callers
where 's' is not NUL-terminated.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
arch/xtensa/platforms/iss/console.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
index 8b95221375a8..8e54625cb2ba 100644
--- a/arch/xtensa/platforms/iss/console.c
+++ b/arch/xtensa/platforms/iss/console.c
@@ -166,8 +166,9 @@ late_initcall(rs_init);
static void iss_console_write(struct console *co, const char *s, unsigned count)
{
- if (s && *s != 0)
- simc_write(1, s, min(count, strlen(s)));
+ count = s ? strnlen(s, count) : 0;
+ if (count)
+ simc_write(1, s, count);
}
static struct tty_driver* iss_console_device(struct console *c, int *index)
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] tty: xtensa/iss: use strnlen to improve iss_console_write
2026-04-30 9:02 [PATCH] tty: xtensa/iss: use strnlen to improve iss_console_write Thorsten Blum
@ 2026-04-30 9:45 ` Max Filippov
0 siblings, 0 replies; 2+ messages in thread
From: Max Filippov @ 2026-04-30 9:45 UTC (permalink / raw)
To: Thorsten Blum; +Cc: Chris Zankel, linux-kernel
On Thu, Apr 30, 2026 at 2:04 AM Thorsten Blum <thorsten.blum@linux.dev> wrote:
>
> Use strnlen() to limit scanning 's' to 'count' bytes. Use the length of
> 's' to decide if simc_write() should be called instead of dereferencing
> it first and then calling strlen().
>
> With strnlen(), iss_console_write() is further hardened against callers
> where 's' is not NUL-terminated.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> arch/xtensa/platforms/iss/console.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
Thanks. Applied to my xtensa tree.
-- Max
^ permalink raw reply [flat|nested] 2+ messages in thread
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