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Message-ID: <20241026154704.159305-2-thorsten.blum@linux.dev>
Date: Sat, 26 Oct 2024 17:47:04 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Kent Overstreet <kent.overstreet@...ux.dev>,
Kees Cook <kees@...nel.org>,
"Gustavo A. R. Silva" <gustavoars@...nel.org>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
linux-bcachefs@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org
Subject: [RESEND PATCH] bcachefs: Annotate struct bucket_gens with __counted_by()
Add the __counted_by compiler attribute to the flexible array member b
to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.
Use struct_size() to calculate the number of bytes to be allocated.
Update bucket_gens->nbuckets and bucket_gens->nbuckets_minus_first when
resizing.
Compile-tested only.
Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
fs/bcachefs/buckets.c | 13 ++++++++-----
fs/bcachefs/buckets_types.h | 2 +-
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index ec7d9a59bea9..8bd17667e243 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -1266,8 +1266,9 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
BUG_ON(resize && ca->buckets_nouse);
- if (!(bucket_gens = kvmalloc(sizeof(struct bucket_gens) + nbuckets,
- GFP_KERNEL|__GFP_ZERO))) {
+ bucket_gens = kvmalloc(struct_size(bucket_gens, b, nbuckets),
+ GFP_KERNEL|__GFP_ZERO);
+ if (!bucket_gens) {
ret = -BCH_ERR_ENOMEM_bucket_gens;
goto err;
}
@@ -1285,11 +1286,13 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
old_bucket_gens = rcu_dereference_protected(ca->bucket_gens, 1);
if (resize) {
- size_t n = min(bucket_gens->nbuckets, old_bucket_gens->nbuckets);
-
+ bucket_gens->nbuckets = min(bucket_gens->nbuckets,
+ old_bucket_gens->nbuckets);
+ bucket_gens->nbuckets_minus_first =
+ bucket_gens->nbuckets - bucket_gens->first_bucket;
memcpy(bucket_gens->b,
old_bucket_gens->b,
- n);
+ bucket_gens->nbuckets);
}
rcu_assign_pointer(ca->bucket_gens, bucket_gens);
diff --git a/fs/bcachefs/buckets_types.h b/fs/bcachefs/buckets_types.h
index 28bd09a253c8..7174047b8e92 100644
--- a/fs/bcachefs/buckets_types.h
+++ b/fs/bcachefs/buckets_types.h
@@ -24,7 +24,7 @@ struct bucket_gens {
u16 first_bucket;
size_t nbuckets;
size_t nbuckets_minus_first;
- u8 b[];
+ u8 b[] __counted_by(nbuckets);
};
struct bch_dev_usage {
--
2.47.0
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