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authorTejun Heo <htejun@gmail.com>2005-11-10 08:55:01 +0100
committerJens Axboe <axboe@nelson.home.kernel.dk>2005-11-12 10:56:21 +0100
commitbe56123568072d223263a6a70a087d1e7faabb83 (patch)
treee6044bff3c9dba3392dfe1a4b172d87081d55334 /block
parent15853af9f07673680439b224519c692f1352b959 (diff)
downloadlinux-2.6.34-ux500-be56123568072d223263a6a70a087d1e7faabb83.tar.gz
[BLOCK] fix string handling in elv_iosched_store
elv_iosched_store doesn't terminate string passed from userspace if it's too long. Also, if the written length is zero (probably not possible), it accesses elevator_name[-1]. This patch fixes both bugs. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block')
-rw-r--r--block/elevator.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 73aa46b6db4..cacfff7418e 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -762,13 +762,15 @@ error:
ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count)
{
char elevator_name[ELV_NAME_MAX];
+ size_t len;
struct elevator_type *e;
- memset(elevator_name, 0, sizeof(elevator_name));
- strncpy(elevator_name, name, sizeof(elevator_name));
+ elevator_name[sizeof(elevator_name) - 1] = '\0';
+ strncpy(elevator_name, name, sizeof(elevator_name) - 1);
+ len = strlen(elevator_name);
- if (elevator_name[strlen(elevator_name) - 1] == '\n')
- elevator_name[strlen(elevator_name) - 1] = '\0';
+ if (len && elevator_name[len - 1] == '\n')
+ elevator_name[len - 1] = '\0';
e = elevator_get(elevator_name);
if (!e) {