From: Todd C. Miller <Todd.Miller@courtesan.com>
Date: Sun, 14 Aug 2011 14:44:31 +0000 (-0400)
Subject: Add primitive format string support to the lbuf code.
X-Git-Tag: SUDO_1_7_7~5
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ff6795241926fcb2f3b4a08eb485f8c43b5b99ba;p=sudo

Add primitive format string support to the lbuf code.

--HG--
branch : 1.7
---

diff --git a/lbuf.c b/lbuf.c
index bafea18f8..42db57cc8 100644
--- a/lbuf.c
+++ b/lbuf.c
@@ -104,110 +104,112 @@ lbuf_destroy(lbuf)
 }
 
 /*
- * Append strings to the buffer, expanding it as needed.
+ * Parse the format and append strings, only %s and %% escapes are supported.
+ * Any characters in set are quoted with a backslash.
  */
 void
 #ifdef __STDC__
-lbuf_append_quoted(struct lbuf *lbuf, const char *set, ...)
+lbuf_append_quoted(struct lbuf *lbuf, const char *set, const char *fmt, ...)
 #else
-lbuf_append_quoted(lbuf, set, va_alist)
-	struct lbuf *lbuf;
-	const char *set;
-	va_dcl
+lbuf_append_quoted(lbuf, set, fmt, va_alist)
+       struct lbuf *lbuf;
+       const char *set;
+       const char *fmt;
+       va_dcl
 #endif
 {
     va_list ap;
-    int len = 0;
-    char *cp, *s;
-
-#ifdef __STDC__
-    va_start(ap, set);
-#else
-    va_start(ap);
-#endif
-    while ((s = va_arg(ap, char *)) != NULL) {
-	len += strlen(s);
-	for (cp = s; (cp = strpbrk(cp, set)) != NULL; cp++)
-	    len++;
-    }
-    va_end(ap);
-
-    /* Expand buffer as needed. */
-    if (lbuf->len + len >= lbuf->size) {
-	do {
-	    lbuf->size += 256;
-	} while (lbuf->len + len >= lbuf->size);
-	lbuf->buf = erealloc(lbuf->buf, lbuf->size);
-    }
+    int len;
+    char *cp, *s = NULL;
 
 #ifdef __STDC__
-    va_start(ap, set);
+    va_start(ap, fmt);
 #else
     va_start(ap);
 #endif
-    /* Append each string. */
-    while ((s = va_arg(ap, char *)) != NULL) {
-	while ((cp = strpbrk(s, set)) != NULL) {
-	    len = (int)(cp - s);
-	    memcpy(lbuf->buf + lbuf->len, s, len);
-	    lbuf->len += len;
-	    lbuf->buf[lbuf->len++] = '\\';
-	    lbuf->buf[lbuf->len++] = *cp;
-	    s = cp + 1;
-	}
-	if (*s != '\0') {
+    while (*fmt != '\0') {
+	len = 1;
+	if (fmt[0] == '%' && fmt[1] == 's') {
+	    s = va_arg(ap, char *);
 	    len = strlen(s);
-	    memcpy(lbuf->buf + lbuf->len, s, len);
-	    lbuf->len += len;
 	}
+	/* Assume worst case that all chars must be escaped. */
+	if (lbuf->len + (len * 2) + 1 >= lbuf->size) {
+	    do {
+		lbuf->size += 256;
+	    } while (lbuf->len + len + 1 >= lbuf->size);
+	    lbuf->buf = erealloc(lbuf->buf, lbuf->size);
+	}
+	if (*fmt == '%') {
+	    if (*(++fmt) == 's') {
+		while ((cp = strpbrk(s, set)) != NULL) {
+		    len = (int)(cp - s);
+		    memcpy(lbuf->buf + lbuf->len, s, len);
+		    lbuf->len += len;
+		    lbuf->buf[lbuf->len++] = '\\';
+		    lbuf->buf[lbuf->len++] = *cp;
+		    s = cp + 1;
+		}
+		if (*s != '\0') {
+		    len = strlen(s);
+		    memcpy(lbuf->buf + lbuf->len, s, len);
+		    lbuf->len += len;
+		}
+		fmt++;
+		continue;
+	    }
+	}
+	if (strchr(set, *fmt) != NULL)
+	    lbuf->buf[lbuf->len++] = '\\';
+	lbuf->buf[lbuf->len++] = *fmt++;
     }
     lbuf->buf[lbuf->len] = '\0';
     va_end(ap);
 }
 
 /*
- * Append strings to the buffer, expanding it as needed.
+ * Parse the format and append strings, only %s and %% escapes are supported.
  */
 void
 #ifdef __STDC__
-lbuf_append(struct lbuf *lbuf, ...)
+lbuf_append(struct lbuf *lbuf, const char *fmt, ...)
 #else
-lbuf_append(lbuf, va_alist)
-	struct lbuf *lbuf;
-	va_dcl
+lbuf_append_quoted(lbuf, fmt, va_alist)
+       struct lbuf *lbuf;
+       const char *fmt;
+       va_dcl
 #endif
 {
     va_list ap;
-    int len = 0;
-    char *s;
-
-#ifdef __STDC__
-    va_start(ap, lbuf);
-#else
-    va_start(ap);
-#endif
-    while ((s = va_arg(ap, char *)) != NULL)
-	len += strlen(s);
-    va_end(ap);
-
-    /* Expand buffer as needed. */
-    if (lbuf->len + len >= lbuf->size) {
-	do {
-	    lbuf->size += 256;
-	} while (lbuf->len + len >= lbuf->size);
-	lbuf->buf = erealloc(lbuf->buf, lbuf->size);
-    }
+    int len;
+    char *s = NULL;
 
 #ifdef __STDC__
-    va_start(ap, lbuf);
+    va_start(ap, fmt);
 #else
     va_start(ap);
 #endif
-    /* Append each string. */
-    while ((s = va_arg(ap, char *)) != NULL) {
-	len = strlen(s);
-	memcpy(lbuf->buf + lbuf->len, s, len);
-	lbuf->len += len;
+    while (*fmt != '\0') {
+	len = 1;
+	if (fmt[0] == '%' && fmt[1] == 's') {
+	    s = va_arg(ap, char *);
+	    len = strlen(s);
+	}
+	if (lbuf->len + len + 1 >= lbuf->size) {
+	    do {
+		lbuf->size += 256;
+	    } while (lbuf->len + len + 1 >= lbuf->size);
+	    lbuf->buf = erealloc(lbuf->buf, lbuf->size);
+	}
+	if (*fmt == '%') {
+	    if (*(++fmt) == 's') {
+		memcpy(lbuf->buf + lbuf->len, s, len);
+		lbuf->len += len;
+		fmt++;
+		continue;
+	    }
+	}
+	lbuf->buf[lbuf->len++] = *fmt++;
     }
     lbuf->buf[lbuf->len] = '\0';
     va_end(ap);
diff --git a/lbuf.h b/lbuf.h
index db6f96451..fabddc748 100644
--- a/lbuf.h
+++ b/lbuf.h
@@ -33,8 +33,8 @@ struct lbuf {
 };
 
 int get_ttycols		__P((void));
-void lbuf_append	__P((struct lbuf *, ...));
-void lbuf_append_quoted	__P((struct lbuf *, const char *, ...));
+void lbuf_append	__P((struct lbuf *, const char *, ...) __printflike(2, 3));
+void lbuf_append_quoted	__P((struct lbuf *, const char *, const char *, ...)) __printflike(3, 4);
 void lbuf_destroy	__P((struct lbuf *));
 void lbuf_init		__P((struct lbuf *, int (*)(const char *), int, const char *));
 void lbuf_print		__P((struct lbuf *));
diff --git a/ldap.c b/ldap.c
index a1cf4a6c8..700b410a8 100644
--- a/ldap.c
+++ b/ldap.c
@@ -1480,7 +1480,7 @@ sudo_ldap_display_defaults(nss, pw, lbuf)
 		else
 		    prefix = ", ";
 		for (p = bv; *p != NULL; p++) {
-		    lbuf_append(lbuf, prefix, (*p)->bv_val, NULL);
+		    lbuf_append(lbuf, "%s%s", prefix, (*p)->bv_val);
 		    prefix = ", ";
 		    count++;
 		}
@@ -1519,7 +1519,7 @@ sudo_ldap_display_entry_short(ld, entry, lbuf)
     struct berval **bv, **p;
     int count = 0;
 
-    lbuf_append(lbuf, "    (", NULL);
+    lbuf_append(lbuf, "    (");
 
     /* get the RunAsUser Values from the entry */
     bv = ldap_get_values_len(ld, entry, "sudoRunAsUser");
@@ -1527,26 +1527,22 @@ sudo_ldap_display_entry_short(ld, entry, lbuf)
 	bv = ldap_get_values_len(ld, entry, "sudoRunAs");
     if (bv != NULL) {
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	}
 	ldap_value_free_len(bv);
     } else
-	lbuf_append(lbuf, def_runas_default, NULL);
+	lbuf_append(lbuf, "%s", def_runas_default);
 
     /* get the RunAsGroup Values from the entry */
     bv = ldap_get_values_len(ld, entry, "sudoRunAsGroup");
     if (bv != NULL) {
-	lbuf_append(lbuf, " : ", NULL);
+	lbuf_append(lbuf, " : ");
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	}
 	ldap_value_free_len(bv);
     }
-    lbuf_append(lbuf, ") ", NULL);
+    lbuf_append(lbuf, ") ");
 
     /* get the Option Values from the entry */
     bv = ldap_get_values_len(ld, entry, "sudoOption");
@@ -1568,7 +1564,7 @@ sudo_ldap_display_entry_short(ld, entry, lbuf)
 		tag = (*p)->bv_val[0] == '!' ?
 		    "NOSETENV: " : "SETENV: ";
 	    if (tag != NULL)
-		lbuf_append(lbuf, tag, NULL);
+		lbuf_append(lbuf, tag);
 	}
 	ldap_value_free_len(bv);
     }
@@ -1577,14 +1573,12 @@ sudo_ldap_display_entry_short(ld, entry, lbuf)
     bv = ldap_get_values_len(ld, entry, "sudoCommand");
     if (bv != NULL) {
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	    count++;
 	}
 	ldap_value_free_len(bv);
     }
-    lbuf_append(lbuf, "\n", NULL);
+    lbuf_append(lbuf, "\n");
 
     return count;
 }
@@ -1604,50 +1598,44 @@ sudo_ldap_display_entry_long(ld, entry, lbuf)
 
     /* extract the dn, only show the first rdn */
     rdn = sudo_ldap_get_first_rdn(ld, entry);
-    lbuf_append(lbuf, "\nLDAP Role: ", rdn ? rdn : "UNKNOWN", "\n", NULL);
+    lbuf_append(lbuf, "\nLDAP Role: %s\n", rdn ? rdn : "UNKNOWN");
     if (rdn)
 	ldap_memfree(rdn);
 
     /* get the RunAsUser Values from the entry */
-    lbuf_append(lbuf, "    RunAsUsers: ", NULL);
+    lbuf_append(lbuf, "    RunAsUsers: ");
     bv = ldap_get_values_len(ld, entry, "sudoRunAsUser");
     if (bv == NULL)
 	bv = ldap_get_values_len(ld, entry, "sudoRunAs");
     if (bv != NULL) {
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	}
 	ldap_value_free_len(bv);
     } else
-	lbuf_append(lbuf, def_runas_default, NULL);
-    lbuf_append(lbuf, "\n", NULL);
+	lbuf_append(lbuf, "%s", def_runas_default);
+    lbuf_append(lbuf, "\n");
 
     /* get the RunAsGroup Values from the entry */
     bv = ldap_get_values_len(ld, entry, "sudoRunAsGroup");
     if (bv != NULL) {
-	lbuf_append(lbuf, "    RunAsGroups: ", NULL);
+	lbuf_append(lbuf, "    RunAsGroups: ");
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	}
 	ldap_value_free_len(bv);
-	lbuf_append(lbuf, "\n", NULL);
+	lbuf_append(lbuf, "\n");
     }
 
     /* get the Option Values from the entry */
     bv = ldap_get_values_len(ld, entry, "sudoOption");
     if (bv != NULL) {
-	lbuf_append(lbuf, "    Options: ", NULL);
+	lbuf_append(lbuf, "    Options: ");
 	for (p = bv; *p != NULL; p++) {
-	    if (p != bv)
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, (*p)->bv_val, NULL);
+	    lbuf_append(lbuf, "%s%s", p != bv ? ", " : "", (*p)->bv_val);
 	}
 	ldap_value_free_len(bv);
-	lbuf_append(lbuf, "\n", NULL);
+	lbuf_append(lbuf, "\n");
     }
 
     /*
@@ -1657,7 +1645,7 @@ sudo_ldap_display_entry_long(ld, entry, lbuf)
     bv = ldap_get_values_len(ld, entry, "sudoOrder");
     if (bv != NULL) {
 	if (*bv != NULL) {
-	    lbuf_append(lbuf, "    Order: ", (*bv)->bv_val, "\n", NULL);
+	    lbuf_append(lbuf, "    Order: %s\n", (*bv)->bv_val);
 	}
 	ldap_value_free_len(bv);
     }
@@ -1665,9 +1653,9 @@ sudo_ldap_display_entry_long(ld, entry, lbuf)
     /* Get the command values from the entry. */
     bv = ldap_get_values_len(ld, entry, "sudoCommand");
     if (bv != NULL) {
-	lbuf_append(lbuf, "    Commands:\n", NULL);
+	lbuf_append(lbuf, "    Commands:\n");
 	for (p = bv; *p != NULL; p++) {
-	    lbuf_append(lbuf, "\t", (*p)->bv_val, "\n", NULL);
+	    lbuf_append(lbuf, "\t%s\n", (*p)->bv_val);
 	    count++;
 	}
 	ldap_value_free_len(bv);
diff --git a/parse.c b/parse.c
index 1da7d0a02..be719d4d1 100644
--- a/parse.c
+++ b/parse.c
@@ -275,33 +275,28 @@ sudo_file_append_cmnd(cs, tags, lbuf)
 
 #ifdef HAVE_SELINUX
     if (cs->role)
-	lbuf_append(lbuf, "ROLE=", cs->role, " ", NULL);
+	lbuf_append(lbuf, "ROLE=%s ", cs->role);
     if (cs->type)
-	lbuf_append(lbuf, "TYPE=", cs->type, " ", NULL);
+	lbuf_append(lbuf, "TYPE=%s ", cs->type);
 #endif /* HAVE_SELINUX */
     if (TAG_CHANGED(setenv)) {
-	lbuf_append(lbuf, cs->tags.setenv ? "SETENV: " :
-	    "NOSETENV: ", NULL);
+	lbuf_append(lbuf, cs->tags.setenv ? "SETENV: " : "NOSETENV: ");
 	tags->setenv = cs->tags.setenv;
     }
     if (TAG_CHANGED(noexec)) {
-	lbuf_append(lbuf, cs->tags.noexec ? "NOEXEC: " :
-	    "EXEC: ", NULL);
+	lbuf_append(lbuf, cs->tags.noexec ? "NOEXEC: " : "EXEC: ");
 	tags->noexec = cs->tags.noexec;
     }
     if (TAG_CHANGED(nopasswd)) {
-	lbuf_append(lbuf, cs->tags.nopasswd ? "NOPASSWD: " :
-	    "PASSWD: ", NULL);
+	lbuf_append(lbuf, cs->tags.nopasswd ? "NOPASSWD: " : "PASSWD: ");
 	tags->nopasswd = cs->tags.nopasswd;
     }
     if (TAG_CHANGED(log_input)) {
-	lbuf_append(lbuf, cs->tags.log_input ? "LOG_INPUT: " :
-	    "NOLOG_INPUT: ", NULL);
+	lbuf_append(lbuf, cs->tags.log_input ? "LOG_INPUT: " : "NOLOG_INPUT: ");
 	tags->log_input = cs->tags.log_input;
     }
     if (TAG_CHANGED(log_output)) {
-	lbuf_append(lbuf, cs->tags.log_output ? "LOG_OUTPUT: " :
-	    "NOLOG_OUTPUT: ", NULL);
+	lbuf_append(lbuf, cs->tags.log_output ? "LOG_OUTPUT: " : "NOLOG_OUTPUT: ");
 	tags->log_output = cs->tags.log_output;
     }
     m = cs->cmnd;
@@ -329,37 +324,37 @@ sudo_file_display_priv_short(pw, us, lbuf)
 	tags.nopasswd = UNSPEC;
 	tags.log_input = UNSPEC;
 	tags.log_output = UNSPEC;
-	lbuf_append(lbuf, "    ", NULL);
+	lbuf_append(lbuf, "    ");
 	tq_foreach_fwd(&priv->cmndlist, cs) {
 	    if (cs != tq_first(&priv->cmndlist))
-		lbuf_append(lbuf, ", ", NULL);
-	    lbuf_append(lbuf, "(", NULL);
+		lbuf_append(lbuf, ", ");
+	    lbuf_append(lbuf, "(");
 	    if (!tq_empty(&cs->runasuserlist)) {
 		tq_foreach_fwd(&cs->runasuserlist, m) {
 		    if (m != tq_first(&cs->runasuserlist))
-			lbuf_append(lbuf, ", ", NULL);
+			lbuf_append(lbuf, ", ");
 		    print_member(lbuf, m->name, m->type, m->negated,
 			RUNASALIAS);
 		}
 	    } else if (tq_empty(&cs->runasgrouplist)) {
-		lbuf_append(lbuf, def_runas_default, NULL);
+		lbuf_append(lbuf, "%s", def_runas_default);
 	    } else {
-		lbuf_append(lbuf, pw->pw_name, NULL);
+		lbuf_append(lbuf, "%s", pw->pw_name);
 	    }
 	    if (!tq_empty(&cs->runasgrouplist)) {
-		lbuf_append(lbuf, " : ", NULL);
+		lbuf_append(lbuf, " : ");
 		tq_foreach_fwd(&cs->runasgrouplist, m) {
 		    if (m != tq_first(&cs->runasgrouplist))
-			lbuf_append(lbuf, ", ", NULL);
+			lbuf_append(lbuf, ", ");
 		    print_member(lbuf, m->name, m->type, m->negated,
 			RUNASALIAS);
 		}
 	    }
-	    lbuf_append(lbuf, ") ", NULL);
+	    lbuf_append(lbuf, ") ");
 	    sudo_file_append_cmnd(cs, &tags, lbuf);
 	    nfound++;
 	}
-	lbuf_append(lbuf, "\n", NULL);
+	lbuf_append(lbuf, "\n");
     }
     return nfound;
 }
@@ -384,35 +379,35 @@ sudo_file_display_priv_long(pw, us, lbuf)
 	tags.nopasswd = UNSPEC;
 	tags.log_input = UNSPEC;
 	tags.log_output = UNSPEC;
-	lbuf_append(lbuf, "\nSudoers entry:\n", NULL);
+	lbuf_append(lbuf, "\nSudoers entry:\n");
 	tq_foreach_fwd(&priv->cmndlist, cs) {
-	    lbuf_append(lbuf, "    RunAsUsers: ", NULL);
+	    lbuf_append(lbuf, "    RunAsUsers: ");
 	    if (!tq_empty(&cs->runasuserlist)) {
 		tq_foreach_fwd(&cs->runasuserlist, m) {
 		    if (m != tq_first(&cs->runasuserlist))
-			lbuf_append(lbuf, ", ", NULL);
+			lbuf_append(lbuf, ", ");
 		    print_member(lbuf, m->name, m->type, m->negated,
 			RUNASALIAS);
 		}
 	    } else if (tq_empty(&cs->runasgrouplist)) {
-		lbuf_append(lbuf, def_runas_default, NULL);
+		lbuf_append(lbuf, "%s", def_runas_default);
 	    } else {
-		lbuf_append(lbuf, pw->pw_name, NULL);
+		lbuf_append(lbuf, "%s", pw->pw_name);
 	    }
-	    lbuf_append(lbuf, "\n", NULL);
+	    lbuf_append(lbuf, "\n");
 	    if (!tq_empty(&cs->runasgrouplist)) {
-		lbuf_append(lbuf, "    RunAsGroups: ", NULL);
+		lbuf_append(lbuf, "    RunAsGroups: ");
 		tq_foreach_fwd(&cs->runasgrouplist, m) {
 		    if (m != tq_first(&cs->runasgrouplist))
-			lbuf_append(lbuf, ", ", NULL);
+			lbuf_append(lbuf, ", ");
 		    print_member(lbuf, m->name, m->type, m->negated,
 			RUNASALIAS);
 		}
-		lbuf_append(lbuf, "\n", NULL);
+		lbuf_append(lbuf, "\n");
 	    }
-	    lbuf_append(lbuf, "    Commands:\n\t", NULL);
+	    lbuf_append(lbuf, "    Commands:\n\t");
 	    sudo_file_append_cmnd(cs, &tags, lbuf);
-	    lbuf_append(lbuf, "\n", NULL);
+	    lbuf_append(lbuf, "\n");
 	    nfound++;
 	}
     }
@@ -479,18 +474,18 @@ sudo_file_display_defaults(nss, pw, lbuf)
 	    case DEFAULTS_CMND:
 		continue;
 	}
-	lbuf_append(lbuf, prefix, NULL);
+	lbuf_append(lbuf, prefix);
 	if (d->val != NULL) {
-	    lbuf_append(lbuf, d->var, d->op == '+' ? "+=" :
-		d->op == '-' ? "-=" : "=", NULL);
+	    lbuf_append(lbuf, "%s%s", d->var, d->op == '+' ? "+=" :
+		d->op == '-' ? "-=" : "=");
 	    if (strpbrk(d->val, " \t") != NULL) {
-		lbuf_append(lbuf, "\"", NULL);
-		lbuf_append_quoted(lbuf, "\"", d->val, NULL);
-		lbuf_append(lbuf, "\"", NULL);
+		lbuf_append(lbuf, "\"");
+		lbuf_append_quoted(lbuf, "\"", "%s", d->val);
+		lbuf_append(lbuf, "\"");
 	    } else
-		lbuf_append_quoted(lbuf, SUDOERS_QUOTED, d->val, NULL);
+		lbuf_append_quoted(lbuf, SUDOERS_QUOTED, "%s", d->val);
 	} else
-	    lbuf_append(lbuf, d->op == FALSE ? "!" : "", d->var, NULL);
+	    lbuf_append(lbuf, "%s%s", d->op == FALSE ? "!" : "", d->var);
 	prefix = ", ";
 	nfound++;
     }
@@ -557,21 +552,21 @@ display_bound_defaults(dtype, lbuf)
 	if (binding != tq_first(&d->binding)) {
 	    binding = tq_first(&d->binding);
 	    if (nfound != 1)
-		lbuf_append(lbuf, "\n", NULL);
-	    lbuf_append(lbuf, "    Defaults", dsep, NULL);
+		lbuf_append(lbuf, "\n");
+	    lbuf_append(lbuf, "    Defaults%s", dsep);
 	    for (m = binding; m != NULL; m = m->next) {
 		if (m != binding)
-		    lbuf_append(lbuf, ",", NULL);
+		    lbuf_append(lbuf, ",");
 		print_member(lbuf, m->name, m->type, m->negated, atype);
-		lbuf_append(lbuf, " ", NULL);
+		lbuf_append(lbuf, " ");
 	    }
 	} else
-	    lbuf_append(lbuf, ", ", NULL);
+	    lbuf_append(lbuf, ", ");
 	if (d->val != NULL) {
-	    lbuf_append(lbuf, d->var, d->op == '+' ? "+=" :
-		d->op == '-' ? "-=" : "=", d->val, NULL);
+	    lbuf_append(lbuf, "%s%s%s", d->var, d->op == '+' ? "+=" :
+		d->op == '-' ? "-=" : "=", d->val);
 	} else
-	    lbuf_append(lbuf, d->op == FALSE ? "!" : "", d->var, NULL);
+	    lbuf_append(lbuf, "%s%s", d->op == FALSE ? "!" : "", d->var);
     }
 
     return nfound;
@@ -639,23 +634,23 @@ _print_member(lbuf, name, type, negated, alias_type)
 
     switch (type) {
 	case ALL:
-	    lbuf_append(lbuf, negated ? "!ALL" : "ALL", NULL);
+	    lbuf_append(lbuf, "%sALL", negated ? "!" : "");
 	    break;
 	case COMMAND:
 	    c = (struct sudo_command *) name;
 	    if (negated)
-		lbuf_append(lbuf, "!", NULL);
-	    lbuf_append_quoted(lbuf, SUDOERS_QUOTED, c->cmnd, NULL);
+		lbuf_append(lbuf, "!");
+	    lbuf_append_quoted(lbuf, SUDOERS_QUOTED, "%s", c->cmnd);
 	    if (c->args) {
-		lbuf_append(lbuf, " ", NULL);
-		lbuf_append_quoted(lbuf, SUDOERS_QUOTED, c->args, NULL);
+		lbuf_append(lbuf, " ");
+		lbuf_append_quoted(lbuf, SUDOERS_QUOTED, "%s", c->args);
 	    }
 	    break;
 	case ALIAS:
 	    if ((a = alias_find(name, alias_type)) != NULL) {
 		tq_foreach_fwd(&a->members, m) {
 		    if (m != tq_first(&a->members))
-			lbuf_append(lbuf, ", ", NULL);
+			lbuf_append(lbuf, ", ");
 		    _print_member(lbuf, m->name, m->type,
 			negated ? !m->negated : m->negated, alias_type);
 		}
@@ -663,7 +658,7 @@ _print_member(lbuf, name, type, negated, alias_type)
 	    }
 	    /* FALLTHROUGH */
 	default:
-	    lbuf_append(lbuf, negated ? "!" : "", name, NULL);
+	    lbuf_append(lbuf, "%s%s", negated ? "!" : "", name);
 	    break;
     }
 }
diff --git a/parse_args.c b/parse_args.c
index ee4245b25..d6fa8426f 100644
--- a/parse_args.c
+++ b/parse_args.c
@@ -353,7 +353,7 @@ usage(fatal)
     ulen = (int)strlen(getprogname()) + 8;
     lbuf_init(&lbuf, fatal ? usage_err : usage_out, ulen, NULL);
     for (i = 0; uvec[i] != NULL; i++) {
-	lbuf_append(&lbuf, "usage: ", getprogname(), uvec[i], NULL);
+	lbuf_append(&lbuf, "usage: %s%s", getprogname(), uvec[i]);
 	lbuf_print(&lbuf);
     }
     lbuf_destroy(&lbuf);
@@ -381,83 +381,76 @@ help()
 
     lbuf_init(&lbuf, usage_out, indent, NULL);
     if (strcmp(pname, "sudoedit") == 0)
-	lbuf_append(&lbuf, pname,  " - edit files as another user\n\n", NULL);
+	lbuf_append(&lbuf, pname,  " - edit files as another user\n\n");
     else
-	lbuf_append(&lbuf, pname,  " - execute a command as another user\n\n", NULL);
+	lbuf_append(&lbuf, pname,  " - execute a command as another user\n\n");
     lbuf_print(&lbuf);
 
     usage(0);
 
-    lbuf_append(&lbuf, "\nOptions:\n", NULL);
+    lbuf_append(&lbuf, "\nOptions:\n");
 #ifdef HAVE_BSD_AUTH_H
     lbuf_append(&lbuf,
-	"  -A            use helper program for password prompting\n", NULL);
+	"  -A            use helper program for password prompting\n");
 #endif
     lbuf_append(&lbuf,
-	"  -a type       use specified BSD authentication type\n", NULL);
+	"  -a type       use specified BSD authentication type\n");
     lbuf_append(&lbuf,
-	"  -b            run command in the background\n", NULL);
+	"  -b            run command in the background\n");
     lbuf_append(&lbuf,
-	"  -C fd         close all file descriptors >= fd\n", NULL);
+	"  -C fd         close all file descriptors >= fd\n");
 #ifdef HAVE_LOGIN_CAP_H
     lbuf_append(&lbuf,
-	"  -c class      run command with specified login class\n", NULL);
+	"  -c class      run command with specified login class\n");
 #endif
     lbuf_append(&lbuf,
-	"  -E            preserve user environment when executing command\n",
-	NULL);
+	"  -E            preserve user environment when executing command\n");
     lbuf_append(&lbuf,
-	"  -e            edit files instead of running a command\n", NULL);
+	"  -e            edit files instead of running a command\n");
     lbuf_append(&lbuf,
-	"  -g group      execute command as the specified group\n", NULL);
+	"  -g group      execute command as the specified group\n");
     lbuf_append(&lbuf,
-	"  -H            set HOME variable to target user's home dir.\n",
-	NULL);
+	"  -H            set HOME variable to target user's home dir.\n");
     lbuf_append(&lbuf,
-	"  -h            display help message and exit\n", NULL);
+	"  -h            display help message and exit\n");
     lbuf_append(&lbuf,
-	"  -i [command]  run a login shell as target user\n", NULL);
+	"  -i [command]  run a login shell as target user\n");
     lbuf_append(&lbuf,
-	"  -K            remove timestamp file completely\n", NULL);
+	"  -K            remove timestamp file completely\n");
     lbuf_append(&lbuf,
-	"  -k            invalidate timestamp file\n", NULL);
+	"  -k            invalidate timestamp file\n");
     lbuf_append(&lbuf,
-	"  -L            list supported sudoers Defaults values\n", NULL);
+	"  -L            list supported sudoers Defaults values\n");
     lbuf_append(&lbuf,
-	"  -l[l] command list user's available commands\n", NULL);
+	"  -l[l] command list user's available commands\n");
     lbuf_append(&lbuf,
-	"  -n            non-interactive mode, will not prompt user\n", NULL);
+	"  -n            non-interactive mode, will not prompt user\n");
     lbuf_append(&lbuf,
-	"  -P            preserve group vector instead of setting to target's\n",
-	NULL);
+	"  -P            preserve group vector instead of setting to target's\n");
     lbuf_append(&lbuf,
-	"  -p prompt     use specified password prompt\n", NULL);
+	"  -p prompt     use specified password prompt\n");
 #ifdef HAVE_SELINUX
     lbuf_append(&lbuf,
-	"  -r role       create SELinux security context with specified role\n",
-	NULL);
+	"  -r role       create SELinux security context with specified role\n");
 #endif
     lbuf_append(&lbuf,
-	"  -S            read password from standard input\n", NULL);
+	"  -S            read password from standard input\n");
     lbuf_append(&lbuf,
-	"  -s [command]  run a shell as target user\n", NULL);
+	"  -s [command]  run a shell as target user\n");
 #ifdef HAVE_SELINUX
     lbuf_append(&lbuf,
-	"  -t type       create SELinux security context with specified role\n",
-	NULL);
+	"  -t type       create SELinux security context with specified role\n");
 #endif
     lbuf_append(&lbuf,
-	"  -U user       when listing, list specified user's privileges\n",
-	NULL);
+	"  -U user       when listing, list specified user's privileges\n");
     lbuf_append(&lbuf,
-	"  -u user       run command (or edit file) as specified user\n", NULL);
+	"  -u user       run command (or edit file) as specified user\n");
     lbuf_append(&lbuf,
-	"  -V            display version information and exit\n", NULL);
+	"  -V            display version information and exit\n");
     lbuf_append(&lbuf,
-	"  -v            update user's timestamp without running a command\n",
-	NULL);
+	"  -v            update user's timestamp without running a command\n");
     lbuf_append(&lbuf,
-	"  --            stop processing command line arguments\n", NULL);
+	"  --            stop processing command line arguments\n");
     lbuf_print(&lbuf);
     lbuf_destroy(&lbuf);
     exit(0);
diff --git a/sudo_nss.c b/sudo_nss.c
index 96303202e..f9dc1128d 100644
--- a/sudo_nss.c
+++ b/sudo_nss.c
@@ -257,33 +257,33 @@ display_privs(snl, pw)
     lbuf_init(&privs, output, 4, NULL);
 
     /* Display defaults from all sources. */
-    lbuf_append(&defs, "Matching Defaults entries for ", pw->pw_name,
-	" on this host:\n", NULL);
+    lbuf_append(&defs, "Matching Defaults entries for %s on this host:\n",
+	pw->pw_name);
     count = 0;
     tq_foreach_fwd(snl, nss) {
 	count += nss->display_defaults(nss, pw, &defs);
     }
     if (count)
-	lbuf_append(&defs, "\n\n", NULL);
+	lbuf_append(&defs, "\n\n");
     else
 	defs.len = 0;
 
     /* Display Runas and Cmnd-specific defaults from all sources. */
     olen = defs.len;
-    lbuf_append(&defs, "Runas and Command-specific defaults for ", pw->pw_name,
-	":\n", NULL);
+    lbuf_append(&defs, "Runas and Command-specific defaults for %s:\n",
+	pw->pw_name);
     count = 0;
     tq_foreach_fwd(snl, nss) {
 	count += nss->display_bound_defaults(nss, pw, &defs);
     }
     if (count)
-	lbuf_append(&defs, "\n\n", NULL);
+	lbuf_append(&defs, "\n\n");
     else
 	defs.len = olen;
 
     /* Display privileges from all sources. */
-    lbuf_append(&privs, "User ", pw->pw_name,
-	" may run the following commands on this host:\n", NULL);
+    lbuf_append(&privs,
+	"User %s may run the following commands on this host:\n", pw->pw_name);
     count = 0;
     tq_foreach_fwd(snl, nss) {
 	count += nss->display_privs(nss, pw, &privs);