Re: [PATCH] init - fix building bug and potential buffer overflow
- Date: Thu, 15 May 2008 10:58:03 -0700
- From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
- Subject: Re: [PATCH] init - fix building bug and potential buffer overflow
On Wed, 14 May 2008 19:44:02 +0400 Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:
> This patch does fix build bug on m68k wich does not have strncat in straight way.
>
> What is more important - my previous patch
>
> commit e662e1cfd434aa234b72fbc781f1d70211cb785b
> Author: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
> Date: Mon May 12 14:02:22 2008 -0700
>
> init: don't lose initcall return values
>
> has introduced potential buffer overflow by wrong calculation
> of string accumulator size.
>
> Many thanks Andreas Schwab and Geert Uytterhoeven for helping
> to catch and fix the bug.
>
> Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
> ---
>
> Index: linux-2.6.git/init/main.c
> ===================================================================
> --- linux-2.6.git.orig/init/main.c 2008-05-14 17:55:10.000000000 +0400
> +++ linux-2.6.git/init/main.c 2008-05-14 19:11:18.000000000 +0400
> @@ -702,7 +702,7 @@ static void __init do_initcalls(void)
>
> for (call = __initcall_start; call < __initcall_end; call++) {
> ktime_t t0, t1, delta;
> - char msgbuf[40];
> + char msgbuf[64];
> int result;
>
> if (initcall_debug) {
> @@ -729,11 +729,11 @@ static void __init do_initcalls(void)
> sprintf(msgbuf, "error code %d ", result);
>
> if (preempt_count() != count) {
> - strncat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
> + strcat(msgbuf, "preemption imbalance ");
> preempt_count() = count;
> }
> if (irqs_disabled()) {
> - strncat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
> + strcat(msgbuf, "disabled interrupts ");
> local_irq_enable();
> }
> if (msgbuf[0]) {
umm, why can't m68k call strncat() from init/main.c??
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