col: make flush_line() a little bit robust

The code is horrible. The core of the problem are signed integers
and no check for the limits.

This patch fixes c->c_column = cur_col; where c_column is "short"
and "cur_col" is int. Let's use "int" for all the variables. It's
really not perfect as for bigger lines it can segfault again...

The patch also removes some unnecessary static variables.

Addresses: https://github.com/karelzak/util-linux/issues/749
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/text-utils/col.c b/text-utils/col.c
index 3d9e15d26..c6b2bdf56 100644
--- a/text-utils/col.c
+++ b/text-utils/col.c
@@ -88,7 +88,7 @@ typedef char CSET;
 typedef struct char_str {
 #define	CS_NORMAL	1
 #define	CS_ALTERNATE	2
-	short		c_column;	/* column character is in */
+	int		c_column;	/* column character is in */
 	CSET		c_set;		/* character set (currently only 2) */
 	wchar_t		c_char;		/* character in question */
 	int		c_width;	/* character width */
@@ -243,7 +243,7 @@ int main(int argc, char **argv)
 		errno = 0;
 		if ((ch = getwchar()) == WEOF) {
 			if (errno == EILSEQ) {
-				warn(NULL);
+				warn(_("failed on line %d"), max_line);
 				ret = EXIT_FAILURE;
 			}
 			break;
@@ -476,8 +476,9 @@ void flush_line(LINE *l)
 	nchars = l->l_line_len;
 
 	if (l->l_needs_sort) {
-		static CHAR *sorted;
-		static int count_size, *count, i, save, sorted_size, tot;
+		static CHAR *sorted = NULL;
+		static int count_size = 0, *count = NULL, sorted_size = 0;
+		int i, tot;
 
 		/*
 		 * Do an O(n) sort on l->l_line by column being careful to
@@ -494,7 +495,7 @@ void flush_line(LINE *l)
 			    (unsigned)sizeof(int) * count_size);
 		}
 		memset(count, 0, sizeof(int) * l->l_max_col + 1);
-		for (i = nchars, c = l->l_line; --i >= 0; c++)
+		for (i = nchars, c = l->l_line; c && --i >= 0; c++)
 			count[c->c_column]++;
 
 		/*
@@ -502,7 +503,7 @@ void flush_line(LINE *l)
 		 * indices into new line.
 		 */
 		for (tot = 0, i = 0; i <= l->l_max_col; i++) {
-			save = count[i];
+			int save = count[i];
 			count[i] = tot;
 			tot += save;
 		}