* [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline
@ 2021-12-27 9:09 Hangyu Hua
2021-12-27 9:19 ` Andreas Schwab
0 siblings, 1 reply; 5+ messages in thread
From: Hangyu Hua @ 2021-12-27 9:09 UTC (permalink / raw)
To: geert; +Cc: linux-m68k, linux-kernel, Hangyu Hua
When the size of commandp >= size, array out of bound write occurs because
len == 0.
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
arch/m68k/kernel/uboot.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/m68k/kernel/uboot.c b/arch/m68k/kernel/uboot.c
index 928dbd33fc4a..05eca6f653b5 100644
--- a/arch/m68k/kernel/uboot.c
+++ b/arch/m68k/kernel/uboot.c
@@ -101,5 +101,8 @@ __init void process_uboot_commandline(char *commandp, int size)
}
parse_uboot_commandline(commandp, len);
- commandp[len - 1] = 0;
+ if (len > 0)
+ commandp[len - 1] = 0;
+ else
+ commandp[0] = 0;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline
2021-12-27 9:09 [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline Hangyu Hua
@ 2021-12-27 9:19 ` Andreas Schwab
2021-12-27 11:52 ` Hangyu Hua
0 siblings, 1 reply; 5+ messages in thread
From: Andreas Schwab @ 2021-12-27 9:19 UTC (permalink / raw)
To: Hangyu Hua; +Cc: geert, linux-m68k, linux-kernel
On Dez 27 2021, Hangyu Hua wrote:
> diff --git a/arch/m68k/kernel/uboot.c b/arch/m68k/kernel/uboot.c
> index 928dbd33fc4a..05eca6f653b5 100644
> --- a/arch/m68k/kernel/uboot.c
> +++ b/arch/m68k/kernel/uboot.c
> @@ -101,5 +101,8 @@ __init void process_uboot_commandline(char *commandp, int size)
> }
>
> parse_uboot_commandline(commandp, len);
> - commandp[len - 1] = 0;
> + if (len > 0)
> + commandp[len - 1] = 0;
> + else
> + commandp[0] = 0;
If len == 0 then even commandp[0] is OOB.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline
2021-12-27 9:19 ` Andreas Schwab
@ 2021-12-27 11:52 ` Hangyu Hua
2021-12-27 11:56 ` Andreas Schwab
0 siblings, 1 reply; 5+ messages in thread
From: Hangyu Hua @ 2021-12-27 11:52 UTC (permalink / raw)
To: Andreas Schwab; +Cc: geert, linux-m68k, linux-kernel
But commandp[len -1] is used to add a zero-terminated. If we don't use
commandp[0]=0 in len == 0,
than commandp will not have a zero-terminated. I think strings may
make some errors beacause of this.
Thanks.
Andreas Schwab <schwab@linux-m68k.org> 于2021年12月27日周一 17:19写道：
>
> On Dez 27 2021, Hangyu Hua wrote:
>
> > diff --git a/arch/m68k/kernel/uboot.c b/arch/m68k/kernel/uboot.c
> > index 928dbd33fc4a..05eca6f653b5 100644
> > --- a/arch/m68k/kernel/uboot.c
> > +++ b/arch/m68k/kernel/uboot.c
> > @@ -101,5 +101,8 @@ __init void process_uboot_commandline(char *commandp, int size)
> > }
> >
> > parse_uboot_commandline(commandp, len);
> > - commandp[len - 1] = 0;
> > + if (len > 0)
> > + commandp[len - 1] = 0;
> > + else
> > + commandp[0] = 0;
>
> If len == 0 then even commandp[0] is OOB.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline
2021-12-27 11:52 ` Hangyu Hua
@ 2021-12-27 11:56 ` Andreas Schwab
2021-12-27 12:50 ` Hangyu Hua
0 siblings, 1 reply; 5+ messages in thread
From: Andreas Schwab @ 2021-12-27 11:56 UTC (permalink / raw)
To: Hangyu Hua; +Cc: geert, linux-m68k, linux-kernel
On Dez 27 2021, Hangyu Hua wrote:
> If we don't use
> commandp[0]=0 in len == 0,
> than commandp will not have a zero-terminated.
That doesn't make sense. There is no room for the zero.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline
2021-12-27 11:56 ` Andreas Schwab
@ 2021-12-27 12:50 ` Hangyu Hua
0 siblings, 0 replies; 5+ messages in thread
From: Hangyu Hua @ 2021-12-27 12:50 UTC (permalink / raw)
To: Andreas Schwab; +Cc: geert, linux-m68k, linux-kernel
You are right. I will resubmit the patch later.
Thanks.
Andreas Schwab <schwab@linux-m68k.org> 于2021年12月27日周一 19:56写道：
>
> On Dez 27 2021, Hangyu Hua wrote:
>
> > If we don't use
> > commandp[0]=0 in len == 0,
> > than commandp will not have a zero-terminated.
>
> That doesn't make sense. There is no room for the zero.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-12-27 12:50 UTC | newest]
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2021-12-27 9:09 [PATCH] m68k/kernel: array out of bound access in process_uboot_commandline Hangyu Hua
2021-12-27 9:19 ` Andreas Schwab
2021-12-27 11:52 ` Hangyu Hua
2021-12-27 11:56 ` Andreas Schwab
2021-12-27 12:50 ` Hangyu Hua
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