[LU-4353] strncmp() used bogusly

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.6.0
• Affects Version/s: Lustre 2.6.0
• Labels: easy patch strncmp
• Severity: 3
• Assignee: John Hammond
• Reporter: John Hammond

Description

There are a few places where strncmp() is used but strcmp() was meant. For example in lod_xattr_set()

        if (S_ISDIR(attr)) {
                if (strncmp(name, XATTR_NAME_LOV, strlen(XATTR_NAME_LOV)) == 0)
                        rc = lod_xattr_set_lov_on_dir(env, dt, buf, name,
                                                      fl, th, capa);
                else
                        rc = dt_xattr_set(env, next, buf, name, fl, th, capa);

Clearly we do not meant to do this for all xattrs whose names start with trusted.lov, but only for those whose name is trusted.lov. There are several more such uses out of the 200-odd calls to strncmp(). mgs_setparam() uses the interesting but wrong condition

strncmp(param, PARAM_LLITE, sizeof(PARAM_LLITE)) == 0

Note: I don't know if these bugs can cause anything bad to happen. But they are bugs and I have seen a few patches in gerrit which would add more.