[PATCH] wifi: mt76: Replace strlcpy with strscpy

[PATCH] wifi: mt76: Replace strlcpy with strscpy

[Azeem Shaikh]

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().

Direct replacement is safe here since DEV_ASSIGN is only used by
TRACE macros and the return values are ignored.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7615/mt7615_trace.h | 2 +-
 drivers/net/wireless/mediatek/mt76/mt76x02_trace.h       | 2 +-
 drivers/net/wireless/mediatek/mt76/mt7921/mt7921_trace.h | 2 +-
 drivers/net/wireless/mediatek/mt76/trace.h               | 2 +-
 drivers/net/wireless/mediatek/mt76/usb_trace.h           | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mt7615_trace.h b/drivers/net/wireless/mediatek/mt76/mt7615/mt7615_trace.h
index d3eb49d83b98..9be5a58a4e6d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mt7615_trace.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mt7615_trace.h
@@ -14,7 +14,7 @@
 
 #define MAXNAME		32
 #define DEV_ENTRY	__array(char, wiphy_name, 32)
-#define DEV_ASSIGN	strlcpy(__entry->wiphy_name,	\
+#define DEV_ASSIGN	strscpy(__entry->wiphy_name,	\
 				wiphy_name(mt76_hw(dev)->wiphy), MAXNAME)
 #define DEV_PR_FMT	"%s"
 #define DEV_PR_ARG	__entry->wiphy_name
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_trace.h b/drivers/net/wireless/mediatek/mt76/mt76x02_trace.h
index 6a98092e996b..11d119cd0f6f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_trace.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_trace.h
@@ -14,7 +14,7 @@
 
 #define MAXNAME		32
 #define DEV_ENTRY	__array(char, wiphy_name, 32)
-#define DEV_ASSIGN	strlcpy(__entry->wiphy_name,	\
+#define DEV_ASSIGN	strscpy(__entry->wiphy_name,	\
 				wiphy_name(mt76_hw(dev)->wiphy), MAXNAME)
 #define DEV_PR_FMT	"%s"
 #define DEV_PR_ARG	__entry->wiphy_name
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mt7921_trace.h b/drivers/net/wireless/mediatek/mt76/mt7921/mt7921_trace.h
index 9bc4db67f352..887d5cfddd01 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mt7921_trace.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mt7921_trace.h
@@ -14,7 +14,7 @@
 
 #define MAXNAME		32
 #define DEV_ENTRY	__array(char, wiphy_name, 32)
-#define DEV_ASSIGN	strlcpy(__entry->wiphy_name,	\
+#define DEV_ASSIGN	strscpy(__entry->wiphy_name,	\
 				wiphy_name(mt76_hw(dev)->wiphy), MAXNAME)
 #define DEV_PR_FMT	"%s"
 #define DEV_PR_ARG	__entry->wiphy_name
diff --git a/drivers/net/wireless/mediatek/mt76/trace.h b/drivers/net/wireless/mediatek/mt76/trace.h
index c3d0ef8e2890..109a07f9733a 100644
--- a/drivers/net/wireless/mediatek/mt76/trace.h
+++ b/drivers/net/wireless/mediatek/mt76/trace.h
@@ -14,7 +14,7 @@
 
 #define MAXNAME		32
 #define DEV_ENTRY	__array(char, wiphy_name, 32)
-#define DEVICE_ASSIGN	strlcpy(__entry->wiphy_name,	\
+#define DEVICE_ASSIGN	strscpy(__entry->wiphy_name,	\
 				wiphy_name(dev->hw->wiphy), MAXNAME)
 #define DEV_PR_FMT	"%s"
 #define DEV_PR_ARG	__entry->wiphy_name
diff --git a/drivers/net/wireless/mediatek/mt76/usb_trace.h b/drivers/net/wireless/mediatek/mt76/usb_trace.h
index f5ab3215af80..7b261ddb2ac6 100644
--- a/drivers/net/wireless/mediatek/mt76/usb_trace.h
+++ b/drivers/net/wireless/mediatek/mt76/usb_trace.h
@@ -14,7 +14,7 @@
 
 #define MAXNAME		32
 #define DEV_ENTRY	__array(char, wiphy_name, 32)
-#define DEV_ASSIGN	strlcpy(__entry->wiphy_name,	\
+#define DEV_ASSIGN	strscpy(__entry->wiphy_name,	\
 				wiphy_name(dev->hw->wiphy), MAXNAME)
 #define DEV_PR_FMT	"%s "
 #define DEV_PR_ARG	__entry->wiphy_name
-- 
2.41.0.255.g8b1d071c50-goog

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kees Cook]

On Mon, Jul 03, 2023 at 06:12:56PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> 
> Direct replacement is safe here since DEV_ASSIGN is only used by
> TRACE macros and the return values are ignored.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>

Looks good -- thing is using return values from the macros.

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Azeem Shaikh]

On Wed, Jul 12, 2023 at 7:54 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Mon, Jul 03, 2023 at 06:12:56PM +0000, Azeem Shaikh wrote:
> > strlcpy() reads the entire source buffer first.
> > This read may exceed the destination size limit.
> > This is both inefficient and can lead to linear read
> > overflows if a source string is not NUL-terminated [1].
> > In an effort to remove strlcpy() completely [2], replace
> > strlcpy() here with strscpy().
> >
> > Direct replacement is safe here since DEV_ASSIGN is only used by
> > TRACE macros and the return values are ignored.
> >
> > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> > [2] https://github.com/KSPP/linux/issues/89
> >
> > Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
>
> Looks good -- thing is using return values from the macros.

Just to confirm, you mean *not* using return values from the macros?

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kees Cook]

On Mon, 03 Jul 2023 18:12:56 +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> 
> [...]

Applied, thanks!

[1/1] wifi: mt76: Replace strlcpy with strscpy
      https://git.kernel.org/kees/c/535c78cbc0c4

Best regards,
-- 
Kees Cook

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kalle Valo]

Kees Cook <keescook@chromium.org> writes:

> On Mon, 03 Jul 2023 18:12:56 +0000, Azeem Shaikh wrote:
>> strlcpy() reads the entire source buffer first.
>> This read may exceed the destination size limit.
>> This is both inefficient and can lead to linear read
>> overflows if a source string is not NUL-terminated [1].
>> In an effort to remove strlcpy() completely [2], replace
>> strlcpy() here with strscpy().
>> 
>> [...]
>
> Applied, thanks!
>
> [1/1] wifi: mt76: Replace strlcpy with strscpy
>       https://git.kernel.org/kees/c/535c78cbc0c4

Why did you take this? mt76 is in active development so risk of
conflicts is high.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kees Cook]

On Thu, Jul 27, 2023 at 07:00:21PM +0300, Kalle Valo wrote:
> Kees Cook <keescook@chromium.org> writes:
> 
> > On Mon, 03 Jul 2023 18:12:56 +0000, Azeem Shaikh wrote:
> >> strlcpy() reads the entire source buffer first.
> >> This read may exceed the destination size limit.
> >> This is both inefficient and can lead to linear read
> >> overflows if a source string is not NUL-terminated [1].
> >> In an effort to remove strlcpy() completely [2], replace
> >> strlcpy() here with strscpy().
> >> 
> >> [...]
> >
> > Applied, thanks!
> >
> > [1/1] wifi: mt76: Replace strlcpy with strscpy
> >       https://git.kernel.org/kees/c/535c78cbc0c4
> 
> Why did you take this? mt76 is in active development so risk of
> conflicts is high.

There didn't seem to be any further activity for 3 weeks, and it was a
relatively mechanical change. I can drop it from my tree. What's needed
for it to be picked up through wireless?

-Kees

-- 
Kees Cook

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kees Cook]

On Tue, Jul 18, 2023 at 12:38:37AM -0400, Azeem Shaikh wrote:
> On Wed, Jul 12, 2023 at 7:54 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > On Mon, Jul 03, 2023 at 06:12:56PM +0000, Azeem Shaikh wrote:
> > > strlcpy() reads the entire source buffer first.
> > > This read may exceed the destination size limit.
> > > This is both inefficient and can lead to linear read
> > > overflows if a source string is not NUL-terminated [1].
> > > In an effort to remove strlcpy() completely [2], replace
> > > strlcpy() here with strscpy().
> > >
> > > Direct replacement is safe here since DEV_ASSIGN is only used by
> > > TRACE macros and the return values are ignored.
> > >
> > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> > > [2] https://github.com/KSPP/linux/issues/89
> > >
> > > Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> >
> > Looks good -- thing is using return values from the macros.
> 
> Just to confirm, you mean *not* using return values from the macros?

I thought I'd replied to this, but I see it didn't happen: yes, I meant
"not using return values". Sorry for the confusion!

-- 
Kees Cook

Re: [PATCH] wifi: mt76: Replace strlcpy with strscpy

[Kalle Valo]

Kees Cook <keescook@chromium.org> writes:

> On Thu, Jul 27, 2023 at 07:00:21PM +0300, Kalle Valo wrote:
>> Kees Cook <keescook@chromium.org> writes:
>> 
>> > On Mon, 03 Jul 2023 18:12:56 +0000, Azeem Shaikh wrote:
>> >> strlcpy() reads the entire source buffer first.
>> >> This read may exceed the destination size limit.
>> >> This is both inefficient and can lead to linear read
>> >> overflows if a source string is not NUL-terminated [1].
>> >> In an effort to remove strlcpy() completely [2], replace
>> >> strlcpy() here with strscpy().
>> >> 
>> >> [...]
>> >
>> > Applied, thanks!
>> >
>> > [1/1] wifi: mt76: Replace strlcpy with strscpy
>> >       https://git.kernel.org/kees/c/535c78cbc0c4
>> 
>> Why did you take this? mt76 is in active development so risk of
>> conflicts is high.
>
> There didn't seem to be any further activity for 3 weeks, and it was a
> relatively mechanical change.

That's because the wireless trees were on a summer break:

https://lore.kernel.org/all/87y1kncuh4.fsf@kernel.org/

> I can drop it from my tree.

Yes, please drop this. And in the future don't take any wireless patches
unless acked by Johannes or me, I want to minimize the risk of conflicts
between the trees. If a patch is missed for whatever reason please let
me know, do not take it to your tree.

> What's needed for it to be picked up through wireless?

I don't know why Felix didn't take this patch but now I assigned it to
me on patchwork:

https://patchwork.kernel.org/project/linux-wireless/patch/20230703181256.3712079-1-azeemshaikh38@gmail.com/

It should be in wireless-next this week.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: wifi: mt76: Replace strlcpy() with strscpy()

[Kalle Valo]

Azeem Shaikh <azeemshaikh38@gmail.com> wrote:

> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> 
> Direct replacement is safe here since DEV_ASSIGN is only used by
> TRACE macros and the return values are ignored.
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>

Patch applied to wireless-next.git, thanks.

d6b484b5cb2a wifi: mt76: Replace strlcpy() with strscpy()

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20230703181256.3712079-1-azeemshaikh38@gmail.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches