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| author | Sungwoo Kim <iam@sung-woo.kim> | 2026-05-12 01:09:29 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-05-12 09:24:16 -0600 |
| commit | 8582792cf23b3d94674d4d838f7cde9a28d0fcaf (patch) | |
| tree | 70a1df2eed6a558472fa9d4b0bf5be01b2e7951a /block | |
| parent | 2c6e6a18a37b905cb584eb0dda3ae482162a81ca (diff) | |
| download | ath-8582792cf23b3d94674d4d838f7cde9a28d0fcaf.tar.gz | |
block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()
pin_user_pages_fast() can partially succeed and return the number of
pages that were actually pinned. However, the bio_integrity_map_user()
does not handle this partial pinning. This leads to a general protection
fault since bvec_from_pages() dereferences an unpinned page address,
which is 0.
To fix this, add a check to verify that all requested memory is pinned.
If partial pinning occurs, unpin the memory and return -EFAULT.
Kernel Oops:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 1061 Comm: nvme-passthroug Not tainted 7.0.0-11783-g90957f9314e8-dirty #16 PREEMPT(lazy)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:bio_integrity_map_user.cold+0x1b0/0x9d6
Fixes: 492c5d455969 ("block: bio-integrity: directly map user buffers")
Acked-by: Chao Shi <cshi008@fiu.edu>
Acked-by: Weidong Zhu <weizhu@fiu.edu>
Acked-by: Dave Tian <daveti@purdue.edu>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://github.com/linux-blktests/blktests/pull/244
Link: https://patch.msgid.link/20260512050929.541397-2-iam@sung-woo.kim
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bio-integrity.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/block/bio-integrity.c b/block/bio-integrity.c index 78e678d4104b6..e796de1a749e3 100644 --- a/block/bio-integrity.c +++ b/block/bio-integrity.c @@ -402,6 +402,24 @@ int bio_integrity_map_user(struct bio *bio, struct iov_iter *iter) if (unlikely(ret < 0)) goto free_bvec; + /* + * Handle partial pinning. This can happen when pin_user_pages_fast() + * returns fewer pages than requested. + */ + if (user_backed_iter(iter) && unlikely(ret != bytes)) { + if (ret > 0) { + int npinned = DIV_ROUND_UP(offset + ret, PAGE_SIZE); + int i; + + for (i = 0; i < npinned; i++) + unpin_user_page(pages[i]); + } + if (pages != stack_pages) + kvfree(pages); + ret = -EFAULT; + goto free_bvec; + } + nr_bvecs = bvec_from_pages(bvec, pages, nr_vecs, bytes, offset, &is_p2p); if (pages != stack_pages) |