2014-08-07 8:43 GMT+02:00 Randy Dunlap <[email protected]>: > On 08/06/14 11:16, Chris Metcalf wrote: >> Using strncpy() will just silently truncate long strings; we should >> instead return an appropriate error. Using strlcpy() would suffer from >> the same problem. Instead, use strnlen()+memcpy(), and add an >> error-checking step to make sure the lengths are reasonable. >> >> I called the convenience wrapper strscpy(), and a case could be made for >> making it more generic (possibly with a better name), but that seems >> outside the scope of this initial commit. > > Well, having looked at the function before I read this comment, my first > thought was that it should be added to lib/string.c for general > availability. > >> >> Signed-off-by: Chris Metcalf <[email protected]> >> --- >> v2: use strnlen instead of strlen >> >> arch/tile/gxio/mpipe.c | 30 +++++++++++++++++++++++++----- >> 1 file changed, 25 insertions(+), 5 deletions(-) >> >> diff --git a/arch/tile/gxio/mpipe.c b/arch/tile/gxio/mpipe.c >> index 5301a9ffbae1..27a56be8d583 100644 >> --- a/arch/tile/gxio/mpipe.c >> +++ b/arch/tile/gxio/mpipe.c >> @@ -29,6 +29,25 @@ >> /* HACK: Avoid pointless "shadow" warnings. */ >> #define link link_shadow >> >> +/* >> + * Use this routine to avoid copying too-long strings. Unlike strncpy >> + * or strlcpy, we don't enable programmers who don't check return codes; >> + * partially-copied strings can be problematic. The routine returns >> + * the total number of bytes copied (including the trailing NUL) or >> + * zero if the buffer wasn't big enough. >> + */ >> +static size_t strscpy(char *dest, const char *src, size_t size) >> +{ >> + size_t ret = strnlen(src, size) + 1; >> + if (ret > size) { >> + if (size) >> + dest[0] = '\0'; >> + return 0; >> + } >> + memcpy(dest, src, ret); >> + return ret; >> +} > > -- > ~Randy
Hi Sounds like a great idea! Do it Chris! Randy? Kind regards Rickard Strandqvist -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
