Add an error flag to the lbuf struct to simplify error checking.

Callers of the lbuf functions now check the error flag to tell if
a memory allocation error ocurred.

include/sudo_lbuf.h

@@ -30,7 +30,8 @@ struct sudo_lbuf {
     int indent;
     int len;
     int size;
-    int cols;
+    short cols;
+    short error;
 };
 
 typedef int (*sudo_lbuf_output_t)(const char *);
@@ -40,11 +41,15 @@ __dso_public void sudo_lbuf_destroy_v1(struct sudo_lbuf *lbuf);
 __dso_public bool sudo_lbuf_append_v1(struct sudo_lbuf *lbuf, const char *fmt, ...) __printflike(2, 3);
 __dso_public bool sudo_lbuf_append_quoted_v1(struct sudo_lbuf *lbuf, const char *set, const char *fmt, ...) __printflike(3, 4);
 __dso_public void sudo_lbuf_print_v1(struct sudo_lbuf *lbuf);
+__dso_public bool sudo_lbuf_error_v1(struct sudo_lbuf *lbuf);
+__dso_public void sudo_lbuf_clearerr_v1(struct sudo_lbuf *lbuf);
 
 #define sudo_lbuf_init(_a, _b, _c, _d, _e) sudo_lbuf_init_v1((_a), (_b), (_c), (_d), (_e))
 #define sudo_lbuf_destroy(_a) sudo_lbuf_destroy_v1((_a))
 #define sudo_lbuf_append sudo_lbuf_append_v1
 #define sudo_lbuf_append_quoted sudo_lbuf_append_quoted_v1
 #define sudo_lbuf_print(_a) sudo_lbuf_print_v1((_a))
+#define sudo_lbuf_error(_a) sudo_lbuf_error_v1((_a))
+#define sudo_lbuf_clearerr(_a) sudo_lbuf_clearerr_v1((_a))
 
 #endif /* SUDO_LBUF_H */

lib/util/lbuf.c

@@ -46,6 +46,7 @@ sudo_lbuf_init_v1(struct sudo_lbuf *lbuf, sudo_lbuf_output_t output,
     lbuf->continuation = continuation;
     lbuf->indent = indent;
     lbuf->cols = cols;
+    lbuf->error = 0;
     lbuf->len = 0;
     lbuf->size = 0;
     lbuf->buf = NULL;
@@ -74,8 +75,10 @@ sudo_lbuf_expand(struct sudo_lbuf *lbuf, int extra)
 	do {
 	    new_size += 256;
 	} while (lbuf->len + extra + 1 >= new_size);
-	if ((new_buf = realloc(lbuf->buf, new_size)) == NULL)
+	if ((new_buf = realloc(lbuf->buf, new_size)) == NULL) {
+	    lbuf->error = 1;
 	    return false;
+	}
 	lbuf->buf = new_buf;
 	lbuf->size = new_size;
     }
@@ -95,6 +98,9 @@ sudo_lbuf_append_quoted_v1(struct sudo_lbuf *lbuf, const char *set, const char *
     va_list ap;
     debug_decl(sudo_lbuf_append_quoted, SUDO_DEBUG_UTIL)
 
+    if (sudo_lbuf_error(lbuf))
+	debug_return_bool(false);
+
     va_start(ap, fmt);
     while (*fmt != '\0') {
 	if (fmt[0] == '%' && fmt[1] == 's') {
@@ -150,6 +156,9 @@ sudo_lbuf_append_v1(struct sudo_lbuf *lbuf, const char *fmt, ...)
     char *s;
     debug_decl(sudo_lbuf_append, SUDO_DEBUG_UTIL)
 
+    if (sudo_lbuf_error(lbuf))
+	debug_return_bool(false);
+
     va_start(ap, fmt);
     while (*fmt != '\0') {
 	if (fmt[0] == '%' && fmt[1] == 's') {
@@ -179,6 +188,7 @@ done:
     debug_return_bool(ret);
 }
 
+/* XXX - check output function return value */
 static void
 sudo_lbuf_println(struct sudo_lbuf *lbuf, char *line, int len)
 {
@@ -240,6 +250,7 @@ sudo_lbuf_println(struct sudo_lbuf *lbuf, char *line, int len)
 /*
  * Print the buffer with word wrap based on the tty width.
  * The lbuf is reset on return.
+ * XXX - check output function return value
  */
 void
 sudo_lbuf_print_v1(struct sudo_lbuf *lbuf)
@@ -280,6 +291,22 @@ sudo_lbuf_print_v1(struct sudo_lbuf *lbuf)
 
 done:
     lbuf->len = 0;		/* reset the buffer for re-use. */
+    lbuf->error = 0;
 
     debug_return;
 }
+
+bool
+sudo_lbuf_error_v1(struct sudo_lbuf *lbuf)
+{
+    if (lbuf != NULL && lbuf->error != 0)
+	return true;
+    return false;
+}
+
+void
+sudo_lbuf_clearerr_v1(struct sudo_lbuf *lbuf)
+{
+    if (lbuf != NULL)
+	lbuf->error = 0;
+}

lib/util/util.exp.in

@@ -61,7 +61,9 @@ sudo_gettime_mono_v1
 sudo_gettime_real_v1
 sudo_lbuf_append_quoted_v1
 sudo_lbuf_append_v1
+sudo_lbuf_clearerr_v1
 sudo_lbuf_destroy_v1
+sudo_lbuf_error_v1
 sudo_lbuf_init_v1
 sudo_lbuf_print_v1
 sudo_lock_file_v1

plugins/sudoers/ldap.c

@@ -2225,6 +2225,7 @@ sudo_ldap_display_defaults(struct sudo_nss *nss, struct passwd *pw,
     filt = sudo_ldap_build_default_filter();
     if (filt == NULL) {
 	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	count = -1;
 	goto done;
     }
     STAILQ_FOREACH(base, &ldap_conf.base, entries) {
@@ -2256,6 +2257,8 @@ sudo_ldap_display_defaults(struct sudo_nss *nss, struct passwd *pw,
     }
     free(filt);
 done:
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(count);
 }
 
@@ -2457,6 +2460,8 @@ sudo_ldap_display_privs(struct sudo_nss *nss, struct passwd *pw,
     }
 
 done:
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(count);
 }
 

plugins/sudoers/parse.c

@@ -354,7 +354,7 @@ done:
 #define	TAG_CHANGED(t) \
 	(TAG_SET(cs->tags.t) && cs->tags.t != tags->t)
 
-static void
+static bool
 sudo_file_append_cmnd(struct cmndspec *cs, struct cmndtag *tags,
     struct sudo_lbuf *lbuf)
 {
@@ -373,31 +373,31 @@ sudo_file_append_cmnd(struct cmndspec *cs, struct cmndtag *tags,
 	sudo_lbuf_append(lbuf, "TYPE=%s ", cs->type);
 #endif /* HAVE_SELINUX */
     if (TAG_CHANGED(setenv)) {
-	sudo_lbuf_append(lbuf, cs->tags.setenv ? "SETENV: " : "NOSETENV: ");
 	tags->setenv = cs->tags.setenv;
+	sudo_lbuf_append(lbuf, tags->setenv ? "SETENV: " : "NOSETENV: ");
     }
     if (TAG_CHANGED(noexec)) {
-	sudo_lbuf_append(lbuf, cs->tags.noexec ? "NOEXEC: " : "EXEC: ");
 	tags->noexec = cs->tags.noexec;
+	sudo_lbuf_append(lbuf, tags->noexec ? "NOEXEC: " : "EXEC: ");
     }
     if (TAG_CHANGED(nopasswd)) {
-	sudo_lbuf_append(lbuf, cs->tags.nopasswd ? "NOPASSWD: " : "PASSWD: ");
 	tags->nopasswd = cs->tags.nopasswd;
+	sudo_lbuf_append(lbuf, tags->nopasswd ? "NOPASSWD: " : "PASSWD: ");
     }
     if (TAG_CHANGED(log_input)) {
-	sudo_lbuf_append(lbuf, cs->tags.log_input ? "LOG_INPUT: " : "NOLOG_INPUT: ");
 	tags->log_input = cs->tags.log_input;
+	sudo_lbuf_append(lbuf, tags->log_input ? "LOG_INPUT: " : "NOLOG_INPUT: ");
     }
     if (TAG_CHANGED(log_output)) {
-	sudo_lbuf_append(lbuf, cs->tags.log_output ? "LOG_OUTPUT: " : "NOLOG_OUTPUT: ");
 	tags->log_output = cs->tags.log_output;
+	sudo_lbuf_append(lbuf, tags->log_output ? "LOG_OUTPUT: " : "NOLOG_OUTPUT: ");
     }
     if (TAG_CHANGED(send_mail)) {
-	sudo_lbuf_append(lbuf, cs->tags.send_mail ? "MAIL: " : "NOMAIL: ");
 	tags->send_mail = cs->tags.send_mail;
+	sudo_lbuf_append(lbuf, tags->send_mail ? "MAIL: " : "NOMAIL: ");
     }
     print_member(lbuf, cs->cmnd, CMNDALIAS);
-    debug_return;
+    debug_return_bool(!sudo_lbuf_error(lbuf));
 }
 
 #define	RUNAS_CHANGED(cs1, cs2) \
@@ -451,11 +451,12 @@ sudo_file_display_priv_short(struct passwd *pw, struct userspec *us,
 		    }
 		}
 		sudo_lbuf_append(lbuf, ") ");
-		tags.noexec = UNSPEC;
-		tags.setenv = UNSPEC;
-		tags.nopasswd = UNSPEC;
 		tags.log_input = UNSPEC;
 		tags.log_output = UNSPEC;
+		tags.noexec = UNSPEC;
+		tags.nopasswd = UNSPEC;
+		tags.send_mail = UNSPEC;
+		tags.setenv = UNSPEC;
 	    } else if (cs != TAILQ_FIRST(&priv->cmndlist)) {
 		sudo_lbuf_append(lbuf, ", ");
 	    }
@@ -606,6 +607,8 @@ sudo_file_display_privs(struct sudo_nss *nss, struct passwd *pw,
 	else
 	    nfound += sudo_file_display_priv_short(pw, us, lbuf);
     }
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
 done:
     debug_return_int(nfound);
 }
@@ -659,6 +662,8 @@ sudo_file_display_defaults(struct sudo_nss *nss, struct passwd *pw,
 	prefix = ", ";
 	nfound++;
     }
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
 done:
     debug_return_int(nfound);
 }
@@ -677,6 +682,8 @@ sudo_file_display_bound_defaults(struct sudo_nss *nss, struct passwd *pw,
     nfound += display_bound_defaults(DEFAULTS_RUNAS, lbuf);
     nfound += display_bound_defaults(DEFAULTS_CMND, lbuf);
 
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(nfound);
 }
 
@@ -738,6 +745,8 @@ display_bound_defaults(int dtype, struct sudo_lbuf *lbuf)
 	    sudo_lbuf_append(lbuf, "%s%s", d->op == false ? "!" : "", d->var);
     }
 
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(nfound);
 }
 
@@ -783,9 +792,9 @@ sudo_file_display_cmnd(struct sudo_nss *nss, struct passwd *pw)
     }
     matched:
     if (match != NULL && !match->negated) {
-	sudo_printf(SUDO_CONV_INFO_MSG, "%s%s%s\n",
+	const int len = sudo_printf(SUDO_CONV_INFO_MSG, "%s%s%s\n",
 	    safe_cmnd, user_args ? " " : "", user_args ? user_args : "");
-	rval = 0;
+	rval = len == -1 ? -1 : 0;
     }
 done:
     debug_return_int(rval);

plugins/sudoers/sssd.c

@@ -1317,6 +1317,8 @@ sudo_sss_display_defaults(struct sudo_nss *nss, struct passwd *pw,
 
     handle->fn_free_result(sss_result);
 done:
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(count);
 }
 
@@ -1572,6 +1574,8 @@ sudo_sss_display_privs(struct sudo_nss *nss, struct passwd *pw,
     if (sss_result != NULL)
 	handle->fn_free_result(sss_result);
 
+    if (sudo_lbuf_error(lbuf))
+	debug_return_int(-1);
     debug_return_int(count);
 }
 

plugins/sudoers/sudo_nss.c

@@ -293,12 +293,17 @@ display_privs(struct sudo_nss_list *snl, struct passwd *pw)
 	pw->pw_name, user_srunhost);
     count = 0;
     TAILQ_FOREACH(nss, snl, entries) {
-	count += nss->display_defaults(nss, pw, &defs);
+	const int n = nss->display_defaults(nss, pw, &defs);
+	if (n == -1)
+	    goto bad;
+	count += n;
     }
-    if (count)
+    if (count) {
 	sudo_lbuf_append(&defs, "\n\n");
-    else
+    } else {
+	/* Undo Defaults header. */
 	defs.len = 0;
+    }
 
     /* Display Runas and Cmnd-specific defaults from all sources. */
     olen = defs.len;
@@ -306,12 +311,17 @@ display_privs(struct sudo_nss_list *snl, struct passwd *pw)
 	pw->pw_name);
     count = 0;
     TAILQ_FOREACH(nss, snl, entries) {
-	count += nss->display_bound_defaults(nss, pw, &defs);
+	const int n = nss->display_bound_defaults(nss, pw, &defs);
+	if (n == -1)
+	    goto bad;
+	count += n;
     }
-    if (count)
+    if (count) {
 	sudo_lbuf_append(&defs, "\n\n");
-    else
+    } else {
+	/* Undo Defaults header. */
 	defs.len = olen;
+    }
 
     /* Display privileges from all sources. */
     sudo_lbuf_append(&privs,
@@ -319,14 +329,21 @@ display_privs(struct sudo_nss_list *snl, struct passwd *pw)
 	pw->pw_name, user_srunhost);
     count = 0;
     TAILQ_FOREACH(nss, snl, entries) {
-	count += nss->display_privs(nss, pw, &privs);
+	const int n = nss->display_privs(nss, pw, &privs);
+	if (n == -1)
+	    goto bad;
+	count += n;
     }
     if (count == 0) {
 	defs.len = 0;
 	privs.len = 0;
-	sudo_lbuf_append(&privs, _("User %s is not allowed to run sudo on %s.\n"),
+	sudo_lbuf_append(&privs,
+	    _("User %s is not allowed to run sudo on %s.\n"),
 	    pw->pw_name, user_shost);
     }
+    if (sudo_lbuf_error(&defs) || sudo_lbuf_error(&privs))
+	goto bad;
+
     sudo_lbuf_print(&defs);
     sudo_lbuf_print(&privs);
 
@@ -334,6 +351,11 @@ display_privs(struct sudo_nss_list *snl, struct passwd *pw)
     sudo_lbuf_destroy(&privs);
 
     debug_return_int(count > 0);
+bad:
+    sudo_lbuf_destroy(&defs);
+    sudo_lbuf_destroy(&privs);
+
+    debug_return_int(-1);
 }
 
 /*
@@ -348,9 +370,14 @@ display_cmnd(struct sudo_nss_list *snl, struct passwd *pw)
     debug_decl(display_cmnd, SUDOERS_DEBUG_NSS)
 
     /* XXX - display_cmnd return value is backwards */
+    /* XXX - doesn't handle commands allowed by one backend denied by another. */
     TAILQ_FOREACH(nss, snl, entries) {
-	if (nss->display_cmnd(nss, pw) == 0)
+	switch (nss->display_cmnd(nss, pw)) {
-	    debug_return_int(true);
+	    case 0:
+		debug_return_int(true);
+	    case -1:
+		debug_return_int(-1);
+	}
     }
     debug_return_int(false);
 }