From b1f3b64d76cf88cc250e5cdd1de783ba9737078e Mon Sep 17 00:00:00 2001 From: Dave Reisner Date: Sat, 8 Sep 2012 11:55:45 -0400 Subject: [PATCH] block: reject invalid queue attribute values Instead of using simple_strtoul which "converts" invalid numbers to 0, use strict_strtoul and perform error checking to ensure that userspace passes us a valid unsigned long. This addresses problems with functions such as writev, which might want to write a trailing newline -- the newline should rightfully be rejected, but the value preceeding it should be preserved. Fixes BZ#46981. Signed-off-by: Dave Reisner Signed-off-by: Jens Axboe --- block/blk-sysfs.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 9628b291f960..ea51d827a0bb 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -26,9 +26,15 @@ queue_var_show(unsigned long var, char *page) static ssize_t queue_var_store(unsigned long *var, const char *page, size_t count) { - char *p = (char *) page; + int err; + unsigned long v; + + err = strict_strtoul(page, 10, &v); + if (err || v > UINT_MAX) + return -EINVAL; + + *var = v; - *var = simple_strtoul(p, &p, 10); return count; } @@ -48,6 +54,9 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count) return -EINVAL; ret = queue_var_store(&nr, page, count); + if (ret < 0) + return ret; + if (nr < BLKDEV_MIN_RQ) nr = BLKDEV_MIN_RQ; @@ -102,6 +111,9 @@ queue_ra_store(struct request_queue *q, const char *page, size_t count) unsigned long ra_kb; ssize_t ret = queue_var_store(&ra_kb, page, count); + if (ret < 0) + return ret; + q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); return ret; @@ -176,6 +188,9 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) page_kb = 1 << (PAGE_CACHE_SHIFT - 10); ssize_t ret = queue_var_store(&max_sectors_kb, page, count); + if (ret < 0) + return ret; + if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) return -EINVAL; @@ -236,6 +251,9 @@ static ssize_t queue_nomerges_store(struct request_queue *q, const char *page, unsigned long nm; ssize_t ret = queue_var_store(&nm, page, count); + if (ret < 0) + return ret; + spin_lock_irq(q->queue_lock); queue_flag_clear(QUEUE_FLAG_NOMERGES, q); queue_flag_clear(QUEUE_FLAG_NOXMERGES, q); @@ -264,6 +282,9 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count) unsigned long val; ret = queue_var_store(&val, page, count); + if (ret < 0) + return ret; + spin_lock_irq(q->queue_lock); if (val == 2) { queue_flag_set(QUEUE_FLAG_SAME_COMP, q); -- 2.30.2