From: Coly Li colyli@suse.de
commit 7a1481267999c02abf4a624515c1b5c7c1fccbd6 upstream.
offset_to_stripe() returns the stripe number (in type unsigned int) from an offset (in type uint64_t) by the following calculation, do_div(offset, d->stripe_size); For large capacity backing device (e.g. 18TB) with small stripe size (e.g. 4KB), the result is 4831838208 and exceeds UINT_MAX. The actual returned value which caller receives is 536870912, due to the overflow.
Indeed in bcache_device_init(), bcache_device->nr_stripes is limited in range [1, INT_MAX]. Therefore all valid stripe numbers in bcache are in range [0, bcache_dev->nr_stripes - 1].
This patch adds a upper limition check in offset_to_stripe(): the max valid stripe number should be less than bcache_device->nr_stripes. If the calculated stripe number from do_div() is equal to or larger than bcache_device->nr_stripe, -EINVAL will be returned. (Normally nr_stripes is less than INT_MAX, exceeding upper limitation doesn't mean overflow, therefore -EOVERFLOW is not used as error code.)
This patch also changes nr_stripes' type of struct bcache_device from 'unsigned int' to 'int', and return value type of offset_to_stripe() from 'unsigned int' to 'int', to match their exact data ranges.
All locations where bcache_device->nr_stripes and offset_to_stripe() are referenced also get updated for the above type change.
Reported-and-tested-by: Ken Raeburn raeburn@redhat.com Signed-off-by: Coly Li colyli@suse.de Cc: stable@vger.kernel.org Link: https://bugzilla.redhat.com/show_bug.cgi?id=1783075 Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/bcache/bcache.h | 2 +- drivers/md/bcache/writeback.c | 14 +++++++++----- drivers/md/bcache/writeback.h | 19 +++++++++++++++++-- 3 files changed, 27 insertions(+), 8 deletions(-)
--- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -264,7 +264,7 @@ struct bcache_device { #define BCACHE_DEV_UNLINK_DONE 2 #define BCACHE_DEV_WB_RUNNING 3 #define BCACHE_DEV_RATE_DW_RUNNING 4 - unsigned int nr_stripes; + int nr_stripes; unsigned int stripe_size; atomic_t *stripe_sectors_dirty; unsigned long *full_dirty_stripes; --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -519,15 +519,19 @@ void bcache_dev_sectors_dirty_add(struct uint64_t offset, int nr_sectors) { struct bcache_device *d = c->devices[inode]; - unsigned int stripe_offset, stripe, sectors_dirty; + unsigned int stripe_offset, sectors_dirty; + int stripe;
if (!d) return;
+ stripe = offset_to_stripe(d, offset); + if (stripe < 0) + return; + if (UUID_FLASH_ONLY(&c->uuids[inode])) atomic_long_add(nr_sectors, &c->flash_dev_dirty_sectors);
- stripe = offset_to_stripe(d, offset); stripe_offset = offset & (d->stripe_size - 1);
while (nr_sectors) { @@ -567,12 +571,12 @@ static bool dirty_pred(struct keybuf *bu static void refill_full_stripes(struct cached_dev *dc) { struct keybuf *buf = &dc->writeback_keys; - unsigned int start_stripe, stripe, next_stripe; + unsigned int start_stripe, next_stripe; + int stripe; bool wrapped = false;
stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned)); - - if (stripe >= dc->disk.nr_stripes) + if (stripe < 0) stripe = 0;
start_stripe = stripe; --- a/drivers/md/bcache/writeback.h +++ b/drivers/md/bcache/writeback.h @@ -33,10 +33,22 @@ static inline uint64_t bcache_dev_sector return ret; }
-static inline unsigned int offset_to_stripe(struct bcache_device *d, +static inline int offset_to_stripe(struct bcache_device *d, uint64_t offset) { do_div(offset, d->stripe_size); + + /* d->nr_stripes is in range [1, INT_MAX] */ + if (unlikely(offset >= d->nr_stripes)) { + pr_err("Invalid stripe %llu (>= nr_stripes %d).\n", + offset, d->nr_stripes); + return -EINVAL; + } + + /* + * Here offset is definitly smaller than INT_MAX, + * return it as int will never overflow. + */ return offset; }
@@ -44,7 +56,10 @@ static inline bool bcache_dev_stripe_dir uint64_t offset, unsigned int nr_sectors) { - unsigned int stripe = offset_to_stripe(&dc->disk, offset); + int stripe = offset_to_stripe(&dc->disk, offset); + + if (stripe < 0) + return false;
while (1) { if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))