The option parsing code of fortune(6) contains a hand-rolled strtonum.
There are several problems with it: fortune won't accept any files
whose name starts with a number larger than 100 and the string
conversion is susceptible to overflow, which leads to bizarre errors:
$ fortune 101dalmatians
percentages must be <= 100
$ fortune 4294967280% all
fortune: no place to put residual probability (-16%)
The patch below fixes both these issues and makes some further minor
simplifications. Now the only impossible names for a fortune file are
the ones matching the regex [0-9][0-9.]*%
Index: fortune.c
===================================================================
RCS file: /var/cvs/src/games/fortune/fortune/fortune.c,v
retrieving revision 1.51
diff -u -p -r1.51 fortune.c
--- fortune.c 10 Jan 2016 13:35:09 -0000 1.51
+++ fortune.c 1 Mar 2016 14:19:22 -0000
@@ -38,6 +38,7 @@
#include <assert.h>
#include <ctype.h>
#include <dirent.h>
+#include <err.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
@@ -330,37 +331,34 @@ form_file_list(char **files, int file_cn
}
for (i = 0; i < file_cnt; i++) {
percent = NO_PROB;
- if (!isdigit((unsigned char)files[i][0]))
- sp = files[i];
- else {
- percent = 0;
- for (sp = files[i]; isdigit((unsigned char)*sp); sp++)
- percent = percent * 10 + *sp - '0';
- if (percent > 100) {
- fprintf(stderr, "percentages must be <= 100\n");
- return 0;
- }
- if (*sp == '.') {
- fprintf(stderr, "percentages must be
integers\n");
- return 0;
- }
+
+ if (isdigit((unsigned char)files[i][0])) {
+ int pos = strspn(files[i], "0123456789.");
+
/*
- * If the number isn't followed by a '%', then
- * it was not a percentage, just the first part
- * of a file name which starts with digits.
+ * Only try to interpret files[i] as a percentage if
+ * it ends in '%'. Otherwise assume it's a file name.
*/
- if (*sp != '%') {
- percent = NO_PROB;
- sp = files[i];
- }
- else if (*++sp == '\0') {
- if (++i >= file_cnt) {
- fprintf(stderr, "percentages must
precede files\n");
- return 0;
- }
- sp = files[i];
+ if (files[i][pos] == '%' && files[i][pos+1] == '\0') {
+ const char *errstr;
+ char *prefix;
+
+ if ((prefix = strndup(files[i], pos)) == NULL)
+ err(1, NULL);
+ if (strchr(prefix, '.') != NULL)
+ errx(1, "percentages must be integers");
+ percent = strtonum(prefix, 0, 100, &errstr);
+ if (errstr != NULL)
+ errx(1, "percentage is %s: %s", errstr,
+ prefix);
+ free(prefix);
+
+ if (++i >= file_cnt)
+ errx(1,
+ "percentages must precede files");
}
}
+ sp = files[i];
if (strcmp(sp, "all") == 0)
sp = FORTDIR;
if (!add_file(percent, sp, NULL, &File_list, &File_tail, NULL))
