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authorMilan Broz <mbroz@redhat.com>2007-12-13 14:16:10 +0000
committerAlasdair G Kergon <agk@redhat.com>2007-12-20 17:32:13 +0000
commit91e106259214b40e992a58fb9417da46868e19b2 (patch)
treed40a2f0aa45427a66d024ce1b29ea7cb24cc770e
parent91212507f93778c09d4c1335207b6f4b995f5ad1 (diff)
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dm crypt: use bio_add_page
Fix possible max_phys_segments violation in cloned dm-crypt bio. In write operation dm-crypt needs to allocate new bio request and run crypto operation on this clone. Cloned request has always the same size, but number of physical segments can be increased and violate max_phys_segments restriction. This can lead to data corruption and serious hardware malfunction. This was observed when using XFS over dm-crypt and at least two HBA controller drivers (arcmsr, cciss) recently. Fix it by using bio_add_page() call (which tests for other restrictions too) instead of constructing own biovec. All versions of dm-crypt are affected by this bug. Cc: stable@kernel.org Cc: dm-crypt@saout.de Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm-crypt.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 30d51a0c011..6b66ee46b87 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -398,7 +398,8 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
struct bio *clone;
unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
- unsigned int i;
+ unsigned i, len;
+ struct page *page;
clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
if (!clone)
@@ -407,10 +408,8 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
clone_init(io, clone);
for (i = 0; i < nr_iovecs; i++) {
- struct bio_vec *bv = bio_iovec_idx(clone, i);
-
- bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
- if (!bv->bv_page)
+ page = mempool_alloc(cc->page_pool, gfp_mask);
+ if (!page)
break;
/*
@@ -421,15 +420,14 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
if (i == (MIN_BIO_PAGES - 1))
gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
- bv->bv_offset = 0;
- if (size > PAGE_SIZE)
- bv->bv_len = PAGE_SIZE;
- else
- bv->bv_len = size;
+ len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
+
+ if (!bio_add_page(clone, page, len, 0)) {
+ mempool_free(page, cc->page_pool);
+ break;
+ }
- clone->bi_size += bv->bv_len;
- clone->bi_vcnt++;
- size -= bv->bv_len;
+ size -= len;
}
if (!clone->bi_size) {