On 01 15:16:55, Kent Overstreet wrote: > On Fri, May 02, 2025 at 02:41:50AM +0800, Alan Huang wrote: > > This reverts commit 86e92eeeb23741a072fe7532db663250ff2e726a. > > > > 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 > > buffer overflow 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: Alan Huang <[email protected]> > > --- > > fs/bcachefs/xattr_format.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/bcachefs/xattr_format.h b/fs/bcachefs/xattr_format.h > > index c7916011ef34..e9f810539552 100644 > > --- a/fs/bcachefs/xattr_format.h > > +++ b/fs/bcachefs/xattr_format.h > > @@ -13,7 +13,7 @@ struct bch_xattr { > > __u8 x_type; > > __u8 x_name_len; > > __le16 x_val_len; > > - __u8 x_name[] __counted_by(x_name_len); > > + __u8 x_name[]; > > this needs a comment, so we don't make the same mistake again
Better yet: change x_name to x_name_and_value > > > } __packed __aligned(8); > > > > #endif /* _BCACHEFS_XATTR_FORMAT_H */ > > -- > > 2.48.1 > >
