Re: [PATCH] clean up scary strncpy(dst, src, strlen(src)) uses

From: Greg KH
Date: Fri May 31 2013 - 13:11:07 EST


On Fri, May 31, 2013 at 09:18:07AM -0700, Kees Cook wrote:
> Fix various weird constructions of strncpy(dst, src, strlen(src)). Length
> limits should be about the space available in the destination, not
> repurposed as a method to either always include or always exclude
> a trailing NULL byte. Either the NULL should always be copied
> (using strlcpy), or it should not be copied (using something like
> memcpy). Readable code should not depend on the weird behavior of strncpy
> when it hits the length limit. Better to avoid the anti-pattern entirely.
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> This is a follow-up to the anti-pattern being fixed in iscsi-target,
> which was exploitable:
> "iscsi-target: fix heap buffer overflow on error"
> http://git.kernel.org/cgit/linux/kernel/git/nab/target-pending.git/commit/?id=cea4dcfdad926a27a18e188720efe0f2c9403456
> ---
> Documentation/accounting/getdelays.c | 3 ++-
> drivers/acpi/sysfs.c | 3 +--
> drivers/s390/net/qeth_l3_sys.c | 6 ++----
> drivers/staging/tidspbridge/rmgr/drv_interface.c | 3 +--

For the drivers/staging/ part of this:

Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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