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* [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer
@ 2022-09-29  7:29 xu.panda668
  2022-10-04 11:48 ` Will Deacon
  0 siblings, 1 reply; 5+ messages in thread
From: xu.panda668 @ 2022-09-29  7:29 UTC (permalink / raw)
  To: catalin.marinas
  Cc: will, broonie, maz, kristina.martsenko, vladimir.murzin,
	mark.rutland, ardb, linux-arm-kernel, linux-kernel, cgel.zte,
	Xu Panda, Zeal Robot, Xu Panda

From: Xu Panda <xu.panda@zte.com.cn>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda668@gmail.com>
---
 arch/arm64/kernel/idreg-override.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 95133765ed29..61bbec7ef62e 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -246,7 +246,7 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
                        return;

                len = min(len, ARRAY_SIZE(buf) - 1);
-               strncpy(buf, cmdline, len);
+               strscpy(buf, cmdline, len);
                buf[len] = 0;

                if (strcmp(buf, "--") == 0)
-- 
2.15.2

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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer
  2022-09-29  7:29 [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer xu.panda668
@ 2022-10-04 11:48 ` Will Deacon
  2022-10-05 13:57   ` David Laight
  0 siblings, 1 reply; 5+ messages in thread
From: Will Deacon @ 2022-10-04 11:48 UTC (permalink / raw)
  To: xu.panda668
  Cc: catalin.marinas, broonie, maz, kristina.martsenko,
	vladimir.murzin, mark.rutland, ardb, linux-arm-kernel,
	linux-kernel, cgel.zte, Xu Panda, Zeal Robot

On Thu, Sep 29, 2022 at 07:29:06AM +0000, xu.panda668@gmail.com wrote:
> From: Xu Panda <xu.panda@zte.com.cn>
> 
> The implementation of strscpy() is more robust and safer.
> That's now the recommended way to copy NUL terminated strings.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
> Signed-off-by: Xu Panda <xu.panda668@gmail.com>
> ---
>  arch/arm64/kernel/idreg-override.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
> index 95133765ed29..61bbec7ef62e 100644
> --- a/arch/arm64/kernel/idreg-override.c
> +++ b/arch/arm64/kernel/idreg-override.c
> @@ -246,7 +246,7 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
>                         return;
> 
>                 len = min(len, ARRAY_SIZE(buf) - 1);
> -               strncpy(buf, cmdline, len);
> +               strscpy(buf, cmdline, len);
>                 buf[len] = 0;

Aren't we terminating the buffer explicitly here anyway?

Will

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* RE: [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer
  2022-10-04 11:48 ` Will Deacon
@ 2022-10-05 13:57   ` David Laight
  0 siblings, 0 replies; 5+ messages in thread
From: David Laight @ 2022-10-05 13:57 UTC (permalink / raw)
  To: 'Will Deacon', xu.panda668
  Cc: catalin.marinas, broonie, maz, kristina.martsenko,
	vladimir.murzin, mark.rutland, ardb, linux-arm-kernel,
	linux-kernel, cgel.zte, Xu Panda, Zeal Robot

From: Will Deacon
> Sent: 04 October 2022 12:48
> 
> On Thu, Sep 29, 2022 at 07:29:06AM +0000, xu.panda668@gmail.com wrote:
> > From: Xu Panda <xu.panda@zte.com.cn>
> >
> > The implementation of strscpy() is more robust and safer.
> > That's now the recommended way to copy NUL terminated strings.

In this case the input string isn't NUL terminated....

> >
> > Reported-by: Zeal Robot <zealci@zte.com.cn>
> > Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
> > Signed-off-by: Xu Panda <xu.panda668@gmail.com>
> > ---
> >  arch/arm64/kernel/idreg-override.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
> > index 95133765ed29..61bbec7ef62e 100644
> > --- a/arch/arm64/kernel/idreg-override.c
> > +++ b/arch/arm64/kernel/idreg-override.c
> > @@ -246,7 +246,7 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
> >                         return;
> >
> >                 len = min(len, ARRAY_SIZE(buf) - 1);
> > -               strncpy(buf, cmdline, len);
> > +               strscpy(buf, cmdline, len);
> >                 buf[len] = 0;
> 
> Aren't we terminating the buffer explicitly here anyway?

I doubt the code was tested.
It is always wrong regardless of the initial value of 'len'.

I think using strscpy() will delete the last character
and always add two '\0'.

On the face of it, that could probably be a memcpy().

But with the checks you don't need any of the length
checks that memcpy() might be gaining.

OTOH, if the code used parameqn() a few lines lower the
entire copy could be removed.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


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^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer
@ 2022-09-29  7:10 cgel.zte
  0 siblings, 0 replies; 5+ messages in thread
From: cgel.zte @ 2022-09-29  7:10 UTC (permalink / raw)
  To: catalin.marinas
  Cc: will, broonie, maz, kristina.martsenko, vladimir.murzin,
	mark.rutland, ardb, linux-arm-kernel, linux-kernel, cgel.zte,
	Xu Panda, Zeal Robot, Xu Panda

From: Xu Panda <xu.panda@zte.com.cn>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda668@gmail.com>
---
 arch/arm64/kernel/idreg-override.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 95133765ed29..61bbec7ef62e 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -246,7 +246,7 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
                        return;

                len = min(len, ARRAY_SIZE(buf) - 1);
-               strncpy(buf, cmdline, len);
+               strscpy(buf, cmdline, len);
                buf[len] = 0;

                if (strcmp(buf, "--") == 0)
-- 
2.15.2

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer
@ 2022-09-29  6:51 cgel.zte
  0 siblings, 0 replies; 5+ messages in thread
From: cgel.zte @ 2022-09-29  6:51 UTC (permalink / raw)
  To: catalin.marinas
  Cc: will, broonie, maz, kristina.martsenko, vladimir.murzin,
	mark.rutland, ardb, linux-arm-kernel, linux-kernel, cgel.zte,
	Xu Panda, Zeal Robot, Xu Panda

From: Xu Panda <xu.panda@zte.com.cn>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda668@gmail.com>
---
 arch/arm64/kernel/idreg-override.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 95133765ed29..61bbec7ef62e 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -246,7 +246,7 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
                        return;

                len = min(len, ARRAY_SIZE(buf) - 1);
-               strncpy(buf, cmdline, len);
+               strscpy(buf, cmdline, len);
                buf[len] = 0;

                if (strcmp(buf, "--") == 0)
-- 
2.15.2

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 5+ messages in thread

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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-09-29  7:29 [PATCH linux-next] arm64/idreg: use strscpy() is more robust and safer xu.panda668
2022-10-04 11:48 ` Will Deacon
2022-10-05 13:57   ` David Laight
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2022-09-29  7:10 cgel.zte
2022-09-29  6:51 cgel.zte

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