From: Eric Biggers <ebiggers@xxxxxxxxxx>
Callers of bio_clone_fast() may use a gfp_mask that excludes
GFP_DIRECT_RECLAIM. For example, map_request() uses GFP_ATOMIC.
If this were to happen, the mempool_alloc() in __bio_crypt_clone() can
fail, causing a NULL dereference.
In reality map_request() currently never has to clone an encryption
context, since inline encryption isn't yet supported on device-mapper
devices at all, let alone on request-based ones.
But it is fragile to rely on this. Just make bio_crypt_clone() able to
fail, similar to bio_integrity_clone().
Reported-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Satya Tangirala <satyat@xxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
block/bio.c | 20 +++++++++-----------
block/blk-crypto.c | 5 ++++-
block/bounce.c | 19 +++++++++----------
drivers/md/dm.c | 7 ++++---
include/linux/blk-crypto.h | 9 +++++----
5 files changed, 31 insertions(+), 29 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index a9931f23d9332..b42e046b12eb3 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -713,20 +713,18 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
__bio_clone_fast(b, bio);
- bio_crypt_clone(b, bio, gfp_mask);
+ if (bio_crypt_clone(b, bio, gfp_mask) < 0)
+ goto err_put;
- if (bio_integrity(bio)) {
- int ret;
-
- ret = bio_integrity_clone(b, bio, gfp_mask);
-
- if (ret < 0) {
- bio_put(b);
- return NULL;
- }
- }
+ if (bio_integrity(bio) &&
+ bio_integrity_clone(b, bio, gfp_mask) < 0)
+ goto err_put;
return b;
+
+err_put:
+ bio_put(b);
+ return NULL;
}
EXPORT_SYMBOL(bio_clone_fast);
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 2d5e60023b08b..a3f27a19067c9 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -95,10 +95,13 @@ void __bio_crypt_free_ctx(struct bio *bio)
bio->bi_crypt_context = NULL;
}
-void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
+int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
{
dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+ if (!dst->bi_crypt_context)
+ return -ENOMEM;
*dst->bi_crypt_context = *src->bi_crypt_context;
+ return 0;
}
EXPORT_SYMBOL_GPL(__bio_crypt_clone);
diff --git a/block/bounce.c b/block/bounce.c
index 431be88a02405..162a6eee89996 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -267,22 +267,21 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
break;
}
- bio_crypt_clone(bio, bio_src, gfp_mask);
+ if (bio_crypt_clone(bio, bio_src, gfp_mask) < 0)
+ goto err_put;
- if (bio_integrity(bio_src)) {
- int ret;
-
- ret = bio_integrity_clone(bio, bio_src, gfp_mask);
- if (ret < 0) {
- bio_put(bio);
- return NULL;
- }
- }
+ if (bio_integrity(bio_src) &&
+ bio_integrity_clone(bio, bio_src, gfp_mask) < 0)
+ goto err_put;
bio_clone_blkg_association(bio, bio_src);
blkcg_bio_issue_init(bio);
return bio;
+
+err_put:
+ bio_put(bio);
+ return NULL;
}
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index fb0255d25e4b2..e987b417d702f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1326,14 +1326,15 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned len)
{
struct bio *clone = &tio->clone;
+ int r;
__bio_clone_fast(clone, bio);
- bio_crypt_clone(clone, bio, GFP_NOIO);
+ r = bio_crypt_clone(clone, bio, GFP_NOIO);
+ if (r < 0)
+ return r;
if (bio_integrity(bio)) {
- int r;
-
if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
!dm_target_passes_integrity(tio->ti->type))) {
DMWARN("%s: the target %s doesn't support integrity data.",
diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
index e82342907f2b1..d0dba84f6a608 100644
--- a/include/linux/blk-crypto.h
+++ b/include/linux/blk-crypto.h
@@ -112,12 +112,13 @@ static inline bool bio_has_crypt_ctx(struct bio *bio)
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
-void __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
-static inline void bio_crypt_clone(struct bio *dst, struct bio *src,
- gfp_t gfp_mask)
+int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask);
+static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
+ gfp_t gfp_mask)
{
if (bio_has_crypt_ctx(src))
- __bio_crypt_clone(dst, src, gfp_mask);
+ return __bio_crypt_clone(dst, src, gfp_mask);
+ return 0;
}
#endif /* __LINUX_BLK_CRYPTO_H */
base-commit: f75aef392f869018f78cfedf3c320a6b3fcfda6b
--
2.28.0
