From: Jeff Layton It's theoretically possible for a single SETATTR call to come in that sets the mode and the uid/gid. In that case, don't set the ATTR_KILL_S*ID bits since that would trip the BUG() in notify_change. Just fix up the mode to have the same effect. Signed-off-by: Jeff Layton Cc: Neil Brown Cc: "J. Bruce Fields" Cc: Christoph Hellwig Signed-off-by: Andrew Morton --- fs/nfsd/vfs.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff -puN fs/nfsd/vfs.c~knfsd-only-set-attr_kill_sid-if-attr_mode-isnt-being-explicitly-set fs/nfsd/vfs.c --- a/fs/nfsd/vfs.c~knfsd-only-set-attr_kill_sid-if-attr_mode-isnt-being-explicitly-set +++ a/fs/nfsd/vfs.c @@ -370,14 +370,23 @@ nfsd_setattr(struct svc_rqst *rqstp, str if (iap->ia_valid & ATTR_MODE) { iap->ia_mode &= S_IALLUGO; imode = iap->ia_mode |= (imode & ~S_IALLUGO); + /* if changing uid/gid revoke setuid/setgid in mode */ + if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) { + iap->ia_valid |= ATTR_KILL_PRIV; + iap->ia_mode &= ~S_ISUID; + } + if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid) + iap->ia_mode &= ~S_ISGID; + } else { + /* + * Revoke setuid/setgid bit on chown/chgrp + */ + if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) + iap->ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV; + if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid) + iap->ia_valid |= ATTR_KILL_SGID; } - /* Revoke setuid/setgid bit on chown/chgrp */ - if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid) - iap->ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV; - if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid) - iap->ia_valid |= ATTR_KILL_SGID; - /* Change the attributes. */ iap->ia_valid |= ATTR_CTIME; _