[PATCH AUTOSEL 6.11 071/244] block: fix integer overflow in BLKSECDISCARD

Sasha Levin
2024-09-25T11:39:31Z

From: Alexey Dobriyan <adobriyan@gmail.com>

[ Upstream commit 697ba0b6ec4ae04afb67d3911799b5e2043b4455 ]

I independently rediscovered

commit 22d24a544b0d49bbcbd61c8c0eaf77d3c9297155
block: fix overflow in blk_ioctl_discard()

but for secure erase.

Same problem:

uint64_t r[2] = {512, 18446744073709551104ULL};
ioctl(fd, BLKSECDISCARD, r);

will enter near infinite loop inside blkdev_issue_secure_erase():

a.out: attempt to access beyond end of device
loop0: rw=5, sector=3399043073, nr_sectors = 1024 limit=2048
bio_check_eod: 3286214 callbacks suppressed

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/9e64057f-650a-46d1-b9f7-34af391536ef@p183
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/ioctl.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index e8e4a4190f183..44257bdfeacbf 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -126,7 +126,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
return -EINVAL;

filemap_invalidate_lock(bdev->bd_mapping);
- err = truncate_bdev_range(bdev, mode, start, start + len - 1);
+ err = truncate_bdev_range(bdev, mode, start, end - 1);
if (err)
goto fail;

@@ -163,7 +163,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode,
static int blk_ioctl_secure_erase(struct block_device *bdev, blk_mode_t mode,
void __user *argp)
{
- uint64_t start, len;
+ uint64_t start, len, end;
uint64_t range[2];
int err;

@@ -178,11 +178,12 @@ static int blk_ioctl_secure_erase(struct block_device *bdev, blk_mode_t mode,
len = range[1];
if ((start & 511) || (len & 511))
return -EINVAL;
- if (start + len > bdev_nr_bytes(bdev))
+ if (check_add_overflow(start, len, &end) ||
+ end > bdev_nr_bytes(bdev))
return -EINVAL;

filemap_invalidate_lock(bdev->bd_mapping);
- err = truncate_bdev_range(bdev, mode, start, start + len - 1);
+ err = truncate_bdev_range(bdev, mode, start, end - 1);
if (!err)
err = blkdev_issue_secure_erase(bdev, start >> 9, len >> 9,
GFP_KERNEL);
--
2.43.0