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* [PATCH v2] net: bonding: Use strscpy() instead of manually-truncated strncpy()
@ 2021-06-02 20:31 Kees Cook
  2021-06-02 20:47 ` Jay Vosburgh
  0 siblings, 1 reply; 3+ messages in thread
From: Kees Cook @ 2021-06-02 20:31 UTC (permalink / raw)
  To: Jay Vosburgh
  Cc: Kees Cook, kernel test robot, Veaceslav Falico, Andy Gospodarek,
	David S. Miller, Jakub Kicinski, linux-kernel, netdev,
	linux-hardening

Silence this warning by just using strscpy_pad() directly:

>> drivers/net/bonding/bond_main.c:4877:3: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
    4877 |   strncpy(params->primary, primary, IFNAMSIZ);
         |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Additionally replace other strncpy() uses, as it is considered deprecated:
https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202102150705.fdR6obB0-lkp@intel.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v2:
 - switch to strscpy_pad() and replace earlier strncpy() too
v1: https://lore.kernel.org/lkml/20210602181133.3326856-1-keescook@chromium.org
---
 drivers/net/bonding/bond_main.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index c5a646d06102..e9cb716ad849 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -620,7 +620,7 @@ static int bond_check_dev_link(struct bonding *bond,
 		 */
 
 		/* Yes, the mii is overlaid on the ifreq.ifr_ifru */
-		strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
+		strscpy_pad(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
 		mii = if_mii(&ifr);
 		if (ioctl(slave_dev, &ifr, SIOCGMIIPHY) == 0) {
 			mii->reg_num = MII_BMSR;
@@ -5329,10 +5329,8 @@ static int bond_check_params(struct bond_params *params)
 			(struct reciprocal_value) { 0 };
 	}
 
-	if (primary) {
-		strncpy(params->primary, primary, IFNAMSIZ);
-		params->primary[IFNAMSIZ - 1] = 0;
-	}
+	if (primary)
+		strscpy_pad(params->primary, primary, sizeof(params->primary));
 
 	memcpy(params->arp_targets, arp_target, sizeof(arp_target));
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] net: bonding: Use strscpy() instead of manually-truncated strncpy()
  2021-06-02 20:31 [PATCH v2] net: bonding: Use strscpy() instead of manually-truncated strncpy() Kees Cook
@ 2021-06-02 20:47 ` Jay Vosburgh
  2021-06-02 20:52   ` Kees Cook
  0 siblings, 1 reply; 3+ messages in thread
From: Jay Vosburgh @ 2021-06-02 20:47 UTC (permalink / raw)
  To: Kees Cook
  Cc: kernel test robot, Veaceslav Falico, Andy Gospodarek,
	David S. Miller, Jakub Kicinski, linux-kernel, netdev,
	linux-hardening

Kees Cook <keescook@chromium.org> wrote:

>Silence this warning by just using strscpy_pad() directly:
>
>>> drivers/net/bonding/bond_main.c:4877:3: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
>    4877 |   strncpy(params->primary, primary, IFNAMSIZ);
>         |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>Additionally replace other strncpy() uses, as it is considered deprecated:
>https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
>
>Reported-by: kernel test robot <lkp@intel.com>
>Link: https://lore.kernel.org/lkml/202102150705.fdR6obB0-lkp@intel.com
>Signed-off-by: Kees Cook <keescook@chromium.org>

	There's one more "strncpy(...); primary[IFNAMSIZ - 1] = 0;" set
in bond_options.c:bond_option_primary_set(), doesn't it also generate
this warning?

	Either way, the change looks good to me.

Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>

	-J


>---
>v2:
> - switch to strscpy_pad() and replace earlier strncpy() too
>v1: https://lore.kernel.org/lkml/20210602181133.3326856-1-keescook@chromium.org
>---
> drivers/net/bonding/bond_main.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index c5a646d06102..e9cb716ad849 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -620,7 +620,7 @@ static int bond_check_dev_link(struct bonding *bond,
> 		 */
> 
> 		/* Yes, the mii is overlaid on the ifreq.ifr_ifru */
>-		strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
>+		strscpy_pad(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
> 		mii = if_mii(&ifr);
> 		if (ioctl(slave_dev, &ifr, SIOCGMIIPHY) == 0) {
> 			mii->reg_num = MII_BMSR;
>@@ -5329,10 +5329,8 @@ static int bond_check_params(struct bond_params *params)
> 			(struct reciprocal_value) { 0 };
> 	}
> 
>-	if (primary) {
>-		strncpy(params->primary, primary, IFNAMSIZ);
>-		params->primary[IFNAMSIZ - 1] = 0;
>-	}
>+	if (primary)
>+		strscpy_pad(params->primary, primary, sizeof(params->primary));
> 
> 	memcpy(params->arp_targets, arp_target, sizeof(arp_target));
> 
>-- 
>2.25.1

---
	-Jay Vosburgh, jay.vosburgh@canonical.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] net: bonding: Use strscpy() instead of manually-truncated strncpy()
  2021-06-02 20:47 ` Jay Vosburgh
@ 2021-06-02 20:52   ` Kees Cook
  0 siblings, 0 replies; 3+ messages in thread
From: Kees Cook @ 2021-06-02 20:52 UTC (permalink / raw)
  To: Jay Vosburgh
  Cc: kernel test robot, Veaceslav Falico, Andy Gospodarek,
	David S. Miller, Jakub Kicinski, linux-kernel, netdev,
	linux-hardening

On Wed, Jun 02, 2021 at 01:47:20PM -0700, Jay Vosburgh wrote:
> Kees Cook <keescook@chromium.org> wrote:
> 
> >Silence this warning by just using strscpy_pad() directly:
> >
> >>> drivers/net/bonding/bond_main.c:4877:3: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
> >    4877 |   strncpy(params->primary, primary, IFNAMSIZ);
> >         |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> >Additionally replace other strncpy() uses, as it is considered deprecated:
> >https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
> >
> >Reported-by: kernel test robot <lkp@intel.com>
> >Link: https://lore.kernel.org/lkml/202102150705.fdR6obB0-lkp@intel.com
> >Signed-off-by: Kees Cook <keescook@chromium.org>
> 
> 	There's one more "strncpy(...); primary[IFNAMSIZ - 1] = 0;" set
> in bond_options.c:bond_option_primary_set(), doesn't it also generate
> this warning?

Gah, I was looking only in the same file not the whole directory. :)

v3 on the way!

> 
> 	Either way, the change looks good to me.

Thanks!

> 
> Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
> 
> 	-J
> 
> 
> >---
> >v2:
> > - switch to strscpy_pad() and replace earlier strncpy() too
> >v1: https://lore.kernel.org/lkml/20210602181133.3326856-1-keescook@chromium.org
> >---
> > drivers/net/bonding/bond_main.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> >diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> >index c5a646d06102..e9cb716ad849 100644
> >--- a/drivers/net/bonding/bond_main.c
> >+++ b/drivers/net/bonding/bond_main.c
> >@@ -620,7 +620,7 @@ static int bond_check_dev_link(struct bonding *bond,
> > 		 */
> > 
> > 		/* Yes, the mii is overlaid on the ifreq.ifr_ifru */
> >-		strncpy(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
> >+		strscpy_pad(ifr.ifr_name, slave_dev->name, IFNAMSIZ);
> > 		mii = if_mii(&ifr);
> > 		if (ioctl(slave_dev, &ifr, SIOCGMIIPHY) == 0) {
> > 			mii->reg_num = MII_BMSR;
> >@@ -5329,10 +5329,8 @@ static int bond_check_params(struct bond_params *params)
> > 			(struct reciprocal_value) { 0 };
> > 	}
> > 
> >-	if (primary) {
> >-		strncpy(params->primary, primary, IFNAMSIZ);
> >-		params->primary[IFNAMSIZ - 1] = 0;
> >-	}
> >+	if (primary)
> >+		strscpy_pad(params->primary, primary, sizeof(params->primary));
> > 
> > 	memcpy(params->arp_targets, arp_target, sizeof(arp_target));
> > 
> >-- 
> >2.25.1
> 
> ---
> 	-Jay Vosburgh, jay.vosburgh@canonical.com

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-06-02 20:55 UTC | newest]

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2021-06-02 20:31 [PATCH v2] net: bonding: Use strscpy() instead of manually-truncated strncpy() Kees Cook
2021-06-02 20:47 ` Jay Vosburgh
2021-06-02 20:52   ` Kees Cook

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