From 8ba32fde2c5be52865b2fd7e5e3752a46971fabe Mon Sep 17 00:00:00 2001 From: Kevin Corry Date: Thu, 16 Mar 2006 23:04:03 -0800 Subject: [PATCH] [PATCH] dm stripe: Fix bounds The dm-stripe target currently does not enforce that the size of a stripe device be a multiple of the chunk-size. Under certain conditions, this can lead to I/O requests going off the end of an underlying device. This test-case shows one example. echo "0 100 linear /dev/hdb1 0" | dmsetup create linear0 echo "0 100 linear /dev/hdb1 100" | dmsetup create linear1 echo "0 200 striped 2 32 /dev/mapper/linear0 0 /dev/mapper/linear1 0" | \ dmsetup create stripe0 dd if=/dev/zero of=/dev/mapper/stripe0 bs=1k This will produce the output: dd: writing '/dev/mapper/stripe0': Input/output error 97+0 records in 96+0 records out And in the kernel log will be: attempt to access beyond end of device dm-0: rw=0, want=104, limit=100 The patch will check that the table size is a multiple of the stripe chunk-size when the table is created, which will prevent the above striped device from being created. This should not affect tools like LVM or EVMS, since in all the cases I can think of, striped devices are always created with the sizes being a multiple of the chunk-size. The size of a stripe device must be a multiple of its chunk-size. (akpm: that typecast is quite gratuitous) Signed-off-by: Kevin Corry Signed-off-by: Alasdair G Kergon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/dm-stripe.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index ab89278a56bf..697aacafb02a 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -103,9 +103,15 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) return -EINVAL; } + if (((uint32_t)ti->len) & (chunk_size - 1)) { + ti->error = "dm-stripe: Target length not divisible by " + "chunk size"; + return -EINVAL; + } + width = ti->len; if (sector_div(width, stripes)) { - ti->error = "dm-stripe: Target length not divisable by " + ti->error = "dm-stripe: Target length not divisible by " "number of stripes"; return -EINVAL; }