Commit 6846100b authored by Alan Huang's avatar Alan Huang Committed by Kent Overstreet
Browse files

bcachefs: Remove incorrect __counted_by annotation 

This actually reverts 86e92eee ("bcachefs: Annotate struct bch_xattr
with __counted_by()").

After the x_name, there is a value. According to the disscussion[1],
__counted_by assumes that the flexible array member contains exactly
the amount of elements that are specified. Now there are users came across
a false positive detection of an out of bounds write caused by
the __counted_by here[2], so revert that.

[1] https://lore.kernel.org/lkml/Zv8VDKWN1GzLRT-_@archlinux/T/#m0ce9541c5070146320efd4f928cc1ff8de69e9b2
[2] https://privatebin.net/?a0d4e97d590d71e1#9bLmp2Kb5NU6X6cZEucchDcu88HzUQwHUah8okKPReEt



Signed-off-by: default avatarAlan Huang <mmpgouride@gmail.com>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 28580052

fs/bcachefs/xattr_format.h

+7 −1
Original line number Diff line number Diff line
@@ -13,7 +13,13 @@ struct bch_xattr { 
	__u8			x_type;

	__u8			x_name_len;

	__le16			x_val_len;

	__u8			x_name[] __counted_by(x_name_len);

	/*

	 * x_name contains the name and value counted by

	 * x_name_len + x_val_len. The introduction of

	 * __counted_by(x_name_len) caused a false positive

	 * detection of an out of bounds write.

	 */

	__u8			x_name[];

} __packed __aligned(8);



#endif /* _BCACHEFS_XATTR_FORMAT_H */