Hey, When running in a container with a user namespace, if you call getxattr with name = "system.posix_acl_access" and size % 8 != 4, then getxattr silently skips the user namespace fixup that it normally does resulting in un-fixed-up data being returned. I think that the analysis that this is caused by posix_acl_fix_xattr_to_user() being passed the total buffer size and not the actual size of the xattr as returned by vfs_getxattr() is correct. So this commit passes the actual length of the xattr as returned by vfs_getxattr() down. It might be worth considering making posix_acl_fix_xattr_userns() and posix_acl_fix_xattr_to_user() return errors. Such that e.g. posix_acl_xattr_count() errors can be caught in getxattr(). If that's something we want I can send a follow-up patch. More details of this can be found in https://bugzilla.kernel.org/show_bug.cgi?id=199945 Thanks! Christian Christian Brauner (1): getxattr: use correct xattr length fs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.17.0
