On Wed, 2015-09-09 at 20:51 +0200, Rasmus Villemoes wrote: > On Wed, Sep 09 2015, Joe Perches <j...@perches.com> wrote: > > this makes the sizeof struct printf_spec more than > > 8 bytes which isn't desireable on x86-32. > > I'm pretty sure struct printf_spec > purposely has sizeof==8 to allow it to be (relatively cheaply) passed > around by value.
True. https://lkml.org/lkml/2010/3/6/141 > > %*pb is meant for smallish bitmaps, not big ones. > > Yup. And that leads to my other confusion: Given that the expected > output is given as "0-15", does the bitmap really consist of > S16_MAX > bits with only the first 16 set? No idea. Tejun? Perhaps the code in lib/vsprintf.c that sets spec.field_width and spec.precision from format argument input should be changed to use a temporary int and clamped to S16_MIN -> S16_MAX. Something like: --- lib/vsprintf.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 7f0cdd2..2782129 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1913,13 +1913,21 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) break; } - case FORMAT_TYPE_WIDTH: - spec.field_width = va_arg(args, int); + case FORMAT_TYPE_WIDTH: { + int tmp = va_arg(args, int); + + spec.field_width = (s16)clamp_t(int, tmp, + S16_MIN, S16_MAX); break; + } - case FORMAT_TYPE_PRECISION: - spec.precision = va_arg(args, int); + case FORMAT_TYPE_PRECISION: { + int tmp = va_arg(args, int); + + spec.precision = (s16)clamp_t(int, tmp, + S16_MIN, S16_MAX); break; + } case FORMAT_TYPE_CHAR: { char c; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
