[PATCH] qeth: don't rely on signedness of char

From: Rasmus Villemoes
Date: Sat Dec 05 2015 - 16:33:52 EST


AFAICT, char is unsigned on s390. Relying on that is a little
subtle. The problem here is that if char happens to be signed and
e.g. card->info.mcl_level[2] contains the value -16, the formatted
output will be "fffffff0", thus overflowing card->info.mcl_level
(which has size 5). To help future readers, simply do an explicit mask
so that the value passed to sprintf is in 0-255. If char is indeed
unsigned, gcc should be able to elide the masking.

In any case, the subsequent 0-termination is redundant, since sprintf
has done that.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
drivers/s390/net/qeth_core_main.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 31ac53fa5cee..84bc4b862fbb 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2682,10 +2682,8 @@ void qeth_print_status_message(struct qeth_card *card)
* */
if (!card->info.mcl_level[0]) {
sprintf(card->info.mcl_level, "%02x%02x",
- card->info.mcl_level[2],
- card->info.mcl_level[3]);
-
- card->info.mcl_level[QETH_MCL_LENGTH] = 0;
+ card->info.mcl_level[2] & 0xff,
+ card->info.mcl_level[3] & 0xff);
break;
}
/* fallthrough */
--
2.6.1

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