| Message ID | ZSRmRj7leOsdUmJm@work (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [next] btrfs: Add __counted_by for struct btrfs_delayed_item and use struct_size() | expand |
On Mon, Oct 09, 2023 at 02:44:54PM -0600, Gustavo A. R. Silva wrote: > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for > array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > While there, use struct_size() helper, instead of the open-coded > version, to calculate the size for the allocation of the whole > flexible structure, including of course, the flexible-array member. > > This code was found with the help of Coccinelle, and audited and > fixed manually. > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Looks right to me. Reviewed-by: Kees Cook <keescook@chromium.org>
On Mon, Oct 09, 2023 at 02:44:54PM -0600, Gustavo A. R. Silva wrote: > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for > array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > While there, use struct_size() helper, instead of the open-coded > version, to calculate the size for the allocation of the whole > flexible structure, including of course, the flexible-array member. > > This code was found with the help of Coccinelle, and audited and > fixed manually. > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Added to misc-next, thanks.
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 35d7616615c1..4f364e242341 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -313,7 +313,7 @@ static struct btrfs_delayed_item *btrfs_alloc_delayed_item(u16 data_len, { struct btrfs_delayed_item *item; - item = kmalloc(sizeof(*item) + data_len, GFP_NOFS); + item = kmalloc(struct_size(item, data, data_len), GFP_NOFS); if (item) { item->data_len = data_len; item->type = type; diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h index d050e572c7f9..5cceb31bbd16 100644 --- a/fs/btrfs/delayed-inode.h +++ b/fs/btrfs/delayed-inode.h @@ -95,7 +95,7 @@ struct btrfs_delayed_item { bool logged; /* The maximum leaf size is 64K, so u16 is more than enough. */ u16 data_len; - char data[]; + char data[] __counted_by(data_len); }; static inline void btrfs_init_delayed_root(
Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). While there, use struct_size() helper, instead of the open-coded version, to calculate the size for the allocation of the whole flexible structure, including of course, the flexible-array member. This code was found with the help of Coccinelle, and audited and fixed manually. Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- fs/btrfs/delayed-inode.c | 2 +- fs/btrfs/delayed-inode.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)