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authorDmitry Monakhov <dmonakhov@openvz.org>2017-06-29 11:31:13 -0700
committerJens Axboe <axboe@kernel.dk>2017-07-03 16:56:26 -0600
commitb1fb2c52b2d85f51f36f1661409f9aeef94265ff (patch)
tree26f345624f8f3a8adca8689916b2f9d69282051d /include/linux/bvec.h
parent128b6f9fdd9ace9e56cb3a263b4bc269658f9c40 (diff)
downloadop-kernel-dev-b1fb2c52b2d85f51f36f1661409f9aeef94265ff.zip
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block: guard bvec iteration logic
Currently if some one try to advance bvec beyond it's size we simply dump WARN_ONCE and continue to iterate beyond bvec array boundaries. This simply means that we endup dereferencing/corrupting random memory region. Sane reaction would be to propagate error back to calling context But bvec_iter_advance's calling context is not always good for error handling. For safity reason let truncate iterator size to zero which will break external iteration loop which prevent us from unpredictable memory range corruption. And even it caller ignores an error, it will corrupt it's own bvecs, not others. This patch does: - Return error back to caller with hope that it will react on this - Truncate iterator size Code was added long time ago here 4550dd6c, luckily no one hit it in real life :) Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> [hch: switch to true/false returns instead of errno values] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/bvec.h')
-rw-r--r--include/linux/bvec.h14
1 files changed, 9 insertions, 5 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 89b65b8..de317b4 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -22,6 +22,7 @@
#include <linux/kernel.h>
#include <linux/bug.h>
+#include <linux/errno.h>
/*
* was unsigned short, but we might as well be ready for > 64kB I/O pages
@@ -66,12 +67,14 @@ struct bvec_iter {
.bv_offset = bvec_iter_offset((bvec), (iter)), \
})
-static inline void bvec_iter_advance(const struct bio_vec *bv,
- struct bvec_iter *iter,
- unsigned bytes)
+static inline bool bvec_iter_advance(const struct bio_vec *bv,
+ struct bvec_iter *iter, unsigned bytes)
{
- WARN_ONCE(bytes > iter->bi_size,
- "Attempted to advance past end of bvec iter\n");
+ if (WARN_ONCE(bytes > iter->bi_size,
+ "Attempted to advance past end of bvec iter\n")) {
+ iter->bi_size = 0;
+ return false;
+ }
while (bytes) {
unsigned iter_len = bvec_iter_len(bv, *iter);
@@ -86,6 +89,7 @@ static inline void bvec_iter_advance(const struct bio_vec *bv,
iter->bi_idx++;
}
}
+ return true;
}
#define for_each_bvec(bvl, bio_vec, iter, start) \
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