6.12-stable review patch. If anyone has any objections, please let me know.
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From: Alan Huang mmpgouride@gmail.com
commit 6846100b00d97d3d6f05766ae86a0d821d849e78 upstream.
This actually reverts 86e92eeeb237 ("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/#m0ce9541c50701463... [2] https://privatebin.net/?a0d4e97d590d71e1#9bLmp2Kb5NU6X6cZEucchDcu88HzUQwHUah...
Signed-off-by: Alan Huang mmpgouride@gmail.com Signed-off-by: Kent Overstreet kent.overstreet@linux.dev Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/bcachefs/xattr_format.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/fs/bcachefs/xattr_format.h +++ b/fs/bcachefs/xattr_format.h @@ -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 */