From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: hfsplus: use struct_group_attr() for memcpy() region In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Add struct_group() to mark the "info" region (containing struct DInfo and struct DXInfo structs) in struct hfsplus_cat_folder and struct hfsplus_cat_file that are written into directly, so the compiler can correctly reason about the expected size of the writes. "pahole" shows no size nor member offset changes to struct hfsplus_cat_folder nor struct hfsplus_cat_file. "objdump -d" shows no object code changes. Link: https://lkml.kernel.org/r/20211119192851.1046717-1-keescook@xxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: Zhen Lei <thunder.leizhen@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/hfsplus/hfsplus_raw.h | 12 ++++++++---- fs/hfsplus/xattr.c | 4 ++-- 2 files changed, 10 insertions(+), 6 deletions(-) --- a/fs/hfsplus/hfsplus_raw.h~hfsplus-use-struct_group_attr-for-memcpy-region +++ a/fs/hfsplus/hfsplus_raw.h @@ -260,8 +260,10 @@ struct hfsplus_cat_folder { __be32 access_date; __be32 backup_date; struct hfsplus_perm permissions; - struct DInfo user_info; - struct DXInfo finder_info; + struct_group_attr(info, __packed, + struct DInfo user_info; + struct DXInfo finder_info; + ); __be32 text_encoding; __be32 subfolders; /* Subfolder count in HFSX. Reserved in HFS+. */ } __packed; @@ -294,8 +296,10 @@ struct hfsplus_cat_file { __be32 access_date; __be32 backup_date; struct hfsplus_perm permissions; - struct FInfo user_info; - struct FXInfo finder_info; + struct_group_attr(info, __packed, + struct FInfo user_info; + struct FXInfo finder_info; + ); __be32 text_encoding; u32 reserved2; --- a/fs/hfsplus/xattr.c~hfsplus-use-struct_group_attr-for-memcpy-region +++ a/fs/hfsplus/xattr.c @@ -296,7 +296,7 @@ int __hfsplus_setxattr(struct inode *ino sizeof(hfsplus_cat_entry)); if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) { if (size == folder_finderinfo_len) { - memcpy(&entry.folder.user_info, value, + memcpy(&entry.folder.info, value, folder_finderinfo_len); hfs_bnode_write(cat_fd.bnode, &entry, cat_fd.entryoffset, @@ -309,7 +309,7 @@ int __hfsplus_setxattr(struct inode *ino } } else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) { if (size == file_finderinfo_len) { - memcpy(&entry.file.user_info, value, + memcpy(&entry.file.info, value, file_finderinfo_len); hfs_bnode_write(cat_fd.bnode, &entry, cat_fd.entryoffset, _
