For .RS, we need to save the information how much we actually indented

because negative indents can get truncated, in which case we no longer
know how to restore the original indent at the end of the block.
This also solves another case of effectively infinite output found
by jsg@ with afl, triggered by very large negative indents.

1 files changed, 13 insertions, 27 deletions

diff --git a/man_term.c b/man_term.c
index 713699b5..216b5bb8 100644
--- a/man_term.c
+++ b/man_term.c
@@ -47,7 +47,7 @@ struct	mtermp {
 
 #define	DECL_ARGS	  struct termp *p, \
 			  struct mtermp *mt, \
-			  const struct man_node *n, \
+			  struct man_node *n, \
 			  const struct man_meta *meta
 
 struct	termact {
@@ -280,7 +280,7 @@ static int
 pre_alternate(DECL_ARGS)
 {
 	enum termfont		 font[2];
-	const struct man_node	*nn;
+	struct man_node		*nn;
 	int			 savelit, i;
 
 	switch (n->tok) {
@@ -643,7 +643,7 @@ static int
 pre_TP(DECL_ARGS)
 {
 	struct roffsu		 su;
-	const struct man_node	*nn;
+	struct man_node		*nn;
 	int			 len, savelit;
 
 	switch (n->type) {
@@ -840,7 +840,6 @@ static int
 pre_RS(DECL_ARGS)
 {
 	struct roffsu	 su;
-	int		 len;
 
 	switch (n->type) {
 	case MAN_BLOCK:
@@ -852,17 +851,16 @@ pre_RS(DECL_ARGS)
 		break;
 	}
 
-	len = SHRT_MAX + 1;
-	if ((n = n->parent->head->child) != NULL &&
-	    a2roffsu(n->string, &su, SCALE_EN))
-		len = term_hspan(p, &su);
-	if (len > SHRT_MAX)
-		len = term_len(p, p->defindent);
+	n = n->parent->head;
+	n->aux = SHRT_MAX + 1;
+	if (n->child != NULL && a2roffsu(n->child->string, &su, SCALE_EN))
+		n->aux = term_hspan(p, &su);
+	if (n->aux < 0 && (size_t)(-n->aux) > mt->offset)
+		n->aux = -mt->offset;
+	else if (n->aux > SHRT_MAX)
+		n->aux = term_len(p, p->defindent);
 
-	if (len > 0 || (size_t)(-len) < mt->offset)
-		mt->offset += len;
-	else
-		mt->offset = 0;
+	mt->offset += n->aux;
 	p->offset = mt->offset;
 	p->rmargin = p->maxrmargin;
 
@@ -876,8 +874,6 @@ pre_RS(DECL_ARGS)
 static void
 post_RS(DECL_ARGS)
 {
-	struct roffsu	 su;
-	int		 len;
 
 	switch (n->type) {
 	case MAN_BLOCK:
@@ -889,17 +885,7 @@ post_RS(DECL_ARGS)
 		break;
 	}
 
-	len = SHRT_MAX + 1;
-	if ((n = n->parent->head->child) != NULL &&
-	    a2roffsu(n->string, &su, SCALE_EN))
-		len = term_hspan(p, &su);
-	if (len > SHRT_MAX)
-		len = term_len(p, p->defindent);
-
-	if (len < 0 || (size_t)len < mt->offset)
-		mt->offset -= len;
-	else
-		mt->offset = 0;
+	mt->offset -= n->parent->head->aux;
 	p->offset = mt->offset;
 
 	if (--mt->lmarginsz < MAXMARGINS)