From 1e9e28c63eaf6fb303ca37783e0d0f8e70361aa9 Mon Sep 17 00:00:00 2001
From: Ingo Schwarze <schwarze@openbsd.org>
Date: Sat, 11 Feb 2017 13:24:12 +0000
Subject: Do not prematurely mark intermediate blocks as broken while scanning
 backwards.  Only do so when a block is found that is actually broken. Logic
 error found while investigating crashes reported by tb@.

---
 mdoc_macro.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

(limited to 'mdoc_macro.c')

diff --git a/mdoc_macro.c b/mdoc_macro.c
index 15038f35..3326add6 100644
--- a/mdoc_macro.c
+++ b/mdoc_macro.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_macro.c,v 1.212 2017/02/10 22:19:18 schwarze Exp $ */
+/*	$Id: mdoc_macro.c,v 1.213 2017/02/11 13:24:12 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012-2016 Ingo Schwarze <schwarze@openbsd.org>
@@ -50,6 +50,8 @@ static	int		find_pending(struct roff_man *, int, int, int,
 				struct roff_node *);
 static	int		lookup(struct roff_man *, int, int, int, const char *);
 static	int		macro_or_word(MACRO_PROT_ARGS, int);
+static	void		break_intermediate(struct roff_node *,
+			    struct roff_node *);
 static	int		parse_rest(struct roff_man *, int, int, int *, char *);
 static	int		rew_alt(int);
 static	void		rew_elem(struct roff_man *, int);
@@ -376,6 +378,16 @@ rew_elem(struct roff_man *mdoc, int tok)
 	rew_last(mdoc, n);
 }
 
+static void
+break_intermediate(struct roff_node *n, struct roff_node *breaker)
+{
+	while (n != breaker) {
+		if ( ! (n->flags & NODE_VALID))
+			n->flags |= NODE_BROKEN;
+		n = n->parent;
+	}
+}
+
 /*
  * If there is an open sub-block of the target requiring
  * explicit close-out, postpone closing out the target until
@@ -390,14 +402,12 @@ find_pending(struct roff_man *mdoc, int tok, int line, int ppos,
 
 	irc = 0;
 	for (n = mdoc->last; n != NULL && n != target; n = n->parent) {
-		if (n->flags & NODE_ENDED) {
-			if ( ! (n->flags & NODE_VALID))
-				n->flags |= NODE_BROKEN;
+		if (n->flags & NODE_ENDED)
 			continue;
-		}
 		if (n->type == ROFFT_BLOCK &&
 		    mdoc_macros[n->tok].flags & MDOC_EXPLICIT) {
 			irc = 1;
+			break_intermediate(mdoc->last, n);
 			n->flags |= NODE_BROKEN;
 			if (target->type == ROFFT_HEAD)
 				target->flags |= NODE_ENDED;
@@ -568,11 +578,8 @@ blk_exp_close(MACRO_PROT_ARGS)
 
 	endbody = itblk = later = NULL;
 	for (n = mdoc->last; n; n = n->parent) {
-		if (n->flags & NODE_ENDED) {
-			if ( ! (n->flags & NODE_VALID))
-				n->flags |= NODE_BROKEN;
+		if (n->flags & NODE_ENDED)
 			continue;
-		}
 
 		/*
 		 * Mismatching end macros can never break anything
@@ -599,7 +606,6 @@ blk_exp_close(MACRO_PROT_ARGS)
 		}
 
 		if (atok == n->tok) {
-			assert(body);
 
 			/*
 			 * Found the start of our own block.
@@ -650,6 +656,7 @@ blk_exp_close(MACRO_PROT_ARGS)
 
 		/* Breaking an open sub block. */
 
+		break_intermediate(mdoc->last, body);
 		n->flags |= NODE_BROKEN;
 		if (later == NULL)
 			later = n;
-- 
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