bcache: fix overflow in offset_to_stripe()
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>zero-sugar-mainline-defconfig
parent
65f0f017e7
commit
7a14812679
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@ -264,7 +264,7 @@ struct bcache_device {
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#define BCACHE_DEV_UNLINK_DONE 2
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#define BCACHE_DEV_UNLINK_DONE 2
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#define BCACHE_DEV_WB_RUNNING 3
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#define BCACHE_DEV_WB_RUNNING 3
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#define BCACHE_DEV_RATE_DW_RUNNING 4
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#define BCACHE_DEV_RATE_DW_RUNNING 4
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unsigned int nr_stripes;
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int nr_stripes;
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unsigned int stripe_size;
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unsigned int stripe_size;
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atomic_t *stripe_sectors_dirty;
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atomic_t *stripe_sectors_dirty;
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unsigned long *full_dirty_stripes;
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unsigned long *full_dirty_stripes;
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@ -521,15 +521,19 @@ void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
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uint64_t offset, int nr_sectors)
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uint64_t offset, int nr_sectors)
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{
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{
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struct bcache_device *d = c->devices[inode];
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struct bcache_device *d = c->devices[inode];
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unsigned int stripe_offset, stripe, sectors_dirty;
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unsigned int stripe_offset, sectors_dirty;
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int stripe;
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if (!d)
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if (!d)
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return;
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return;
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stripe = offset_to_stripe(d, offset);
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if (stripe < 0)
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return;
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if (UUID_FLASH_ONLY(&c->uuids[inode]))
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if (UUID_FLASH_ONLY(&c->uuids[inode]))
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atomic_long_add(nr_sectors, &c->flash_dev_dirty_sectors);
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atomic_long_add(nr_sectors, &c->flash_dev_dirty_sectors);
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stripe = offset_to_stripe(d, offset);
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stripe_offset = offset & (d->stripe_size - 1);
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stripe_offset = offset & (d->stripe_size - 1);
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while (nr_sectors) {
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while (nr_sectors) {
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@ -569,12 +573,12 @@ static bool dirty_pred(struct keybuf *buf, struct bkey *k)
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static void refill_full_stripes(struct cached_dev *dc)
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static void refill_full_stripes(struct cached_dev *dc)
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{
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{
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struct keybuf *buf = &dc->writeback_keys;
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struct keybuf *buf = &dc->writeback_keys;
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unsigned int start_stripe, stripe, next_stripe;
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unsigned int start_stripe, next_stripe;
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int stripe;
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bool wrapped = false;
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bool wrapped = false;
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stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned));
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stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned));
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if (stripe < 0)
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if (stripe >= dc->disk.nr_stripes)
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stripe = 0;
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stripe = 0;
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start_stripe = stripe;
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start_stripe = stripe;
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@ -52,10 +52,22 @@ static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
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return ret;
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return ret;
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}
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}
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static inline unsigned int offset_to_stripe(struct bcache_device *d,
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static inline int offset_to_stripe(struct bcache_device *d,
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uint64_t offset)
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uint64_t offset)
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{
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{
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do_div(offset, d->stripe_size);
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do_div(offset, d->stripe_size);
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/* d->nr_stripes is in range [1, INT_MAX] */
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if (unlikely(offset >= d->nr_stripes)) {
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pr_err("Invalid stripe %llu (>= nr_stripes %d).\n",
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offset, d->nr_stripes);
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return -EINVAL;
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}
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/*
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* Here offset is definitly smaller than INT_MAX,
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* return it as int will never overflow.
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*/
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return offset;
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return offset;
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}
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}
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@ -63,7 +75,10 @@ static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
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uint64_t offset,
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uint64_t offset,
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unsigned int nr_sectors)
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unsigned int nr_sectors)
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{
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{
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unsigned int stripe = offset_to_stripe(&dc->disk, offset);
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int stripe = offset_to_stripe(&dc->disk, offset);
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if (stripe < 0)
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return false;
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while (1) {
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while (1) {
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if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
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if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
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