From 7e161bef0bc9d5ea5e6f3dd490ecd5da6f642671 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Sat, 1 Apr 2017 10:01:40 -0400 Subject: getopt: fix fencepost error in ambiguous-W-option handling getopt_long contains an undocumented (AFAICT) feature in which, if you put "W;" in the short-options list, then '-W foo' and '-Wfoo' are treated as equivalent to '--foo'. This is implemented with a partial second copy of the code for handling long options, and that code increments optind one too many times when recovering from an ambiguous abbreviated option, which can cause the main loop to walk past the end of argv and crash. I discovered this while writing a test case that tries to exercise all of getopt's error reporting paths; I wouldn't be surprised to learn that this feature is never used by real applications. * posix/getopt.c (_getopt_internal_r): Don't increment d->optind a second time when reporting ambiguous -W options. --- posix/getopt.c | 1 - 1 file changed, 1 deletion(-) (limited to 'posix/getopt.c') diff --git a/posix/getopt.c b/posix/getopt.c index f1fa0166d8..e616aa6e4d 100644 --- a/posix/getopt.c +++ b/posix/getopt.c @@ -850,7 +850,6 @@ _getopt_internal_r (int argc, char *const *argv, const char *optstring, #endif } d->__nextchar += strlen (d->__nextchar); - d->optind++; return '?'; } if (pfound != NULL) -- cgit v1.2.3