From 55b23bde19c08f14127a27d461a4e079942c7258 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Fri, 27 May 2011 14:50:36 +0200 Subject: [PATCH] xattr: Fix error results for non-existent / invisible attributes Return -ENODATA when trying to read a user.* attribute which cannot exist: user space otherwise does not have a reasonable way to distinguish between non-existent and inaccessible attributes. Likewise, return -ENODATA when an unprivileged process tries to read a trusted.* attribute: to unprivileged processes, those attributes are invisible (listxattr() won't include them). Related to this bug report: https://bugzilla.redhat.com/660613 Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro --- fs/xattr.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/fs/xattr.c b/fs/xattr.c index f1ef94974dea..4be2e7666d02 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -46,18 +46,22 @@ xattr_permission(struct inode *inode, const char *name, int mask) return 0; /* - * The trusted.* namespace can only be accessed by a privileged user. + * The trusted.* namespace can only be accessed by privileged users. */ - if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) - return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM); + if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { + if (!capable(CAP_SYS_ADMIN)) + return (mask & MAY_WRITE) ? -EPERM : -ENODATA; + return 0; + } - /* In user.* namespace, only regular files and directories can have + /* + * In the user.* namespace, only regular files and directories can have * extended attributes. For sticky directories, only the owner and - * privileged user can write attributes. + * privileged users can write attributes. */ if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) - return -EPERM; + return (mask & MAY_WRITE) ? -EPERM : -ENODATA; if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) return -EPERM;