When trying to expand some columns in a table where the sum of the

widths of the remaining columns is already wider than the line
length, underflowing size_t and dying from ENOMEM is the wrong plan.
Instead, simply refrain from expanding anything in such a situation,
avoiding a crash that tb@ found with afl.

3 files changed, 40 insertions, 2 deletions

diff --git a/regress/usr.bin/mandoc/tbl/mod/Makefile b/regress/usr.bin/mandoc/tbl/mod/Makefile
index c5bebb0ff5f..ab087b1e64c 100644
--- a/regress/usr.bin/mandoc/tbl/mod/Makefile
+++ b/regress/usr.bin/mandoc/tbl/mod/Makefile
@@ -1,6 +1,6 @@
-# $OpenBSD: Makefile,v 1.2 2015/02/10 11:02:19 schwarze Exp $
+# $OpenBSD: Makefile,v 1.3 2017/05/01 20:53:58 schwarze Exp $
 
-REGRESS_TARGETS	 = badfont expand font misalign
+REGRESS_TARGETS	 = badfont expand expand-toowide font misalign
 LINT_TARGETS	 = badfont font
 
 # groff-1.22.3 defects:
diff --git a/regress/usr.bin/mandoc/tbl/mod/expand-toowide.in b/regress/usr.bin/mandoc/tbl/mod/expand-toowide.in
new file mode 100644
index 00000000000..7e8a44b81c0
--- /dev/null
+++ b/regress/usr.bin/mandoc/tbl/mod/expand-toowide.in
@@ -0,0 +1,15 @@
+.TH TBL-MOD-EXPAND-TOOWIDE 1 "May 1, 2017" OpenBSD
+.SH NAME
+tbl-mod-expand-toowide \- try to expand columns in a table
+that is already too wide
+.SH DESCRIPTION
+.ll 20n
+In this section, the line length is limited to 20 characters.
+.TS
+tab(:);
+lx l lx.
+x:1234567890:x
+.TE
+.ll 78n
+.PP
+Now we are back to the default terminal width.
diff --git a/regress/usr.bin/mandoc/tbl/mod/expand-toowide.out_ascii b/regress/usr.bin/mandoc/tbl/mod/expand-toowide.out_ascii
new file mode 100644
index 00000000000..066fdf90d5c
--- /dev/null
+++ b/regress/usr.bin/mandoc/tbl/mod/expand-toowide.out_ascii
@@ -0,0 +1,23 @@
+TBL-MOD-EXPAND-TOOWIDE(1)   General Commands Manual  TBL-MOD-EXPAND-TOOWIDE(1)
+
+
+
+NNAAMMEE
+       tbl-mod-expand-toowide - try to expand columns in a table that is
+       already too wide
+
+DDEESSCCRRIIPPTTIIOONN
+       In this
+       section, the
+       line length
+       is limited to
+       20
+       characters.
+
+       x   1234567890   x
+
+       Now we are back to the default terminal width.
+
+
+
+OpenBSD                           May 1, 2017        TBL-MOD-EXPAND-TOOWIDE(1)