From dc48df09cd2a5c7180545ea8fb1be920e0b407ca Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Thu, 17 Apr 2025 17:07:51 -0300 Subject: [PATCH] argp: Fix shift bug From gnulib commits 06094e390b0 and 88033d3779362a. --- argp/argp-parse.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/argp/argp-parse.c b/argp/argp-parse.c index 82c7b784de..99f8d9ecd4 100644 --- a/argp/argp-parse.c +++ b/argp/argp-parse.c @@ -735,12 +735,15 @@ parser_parse_opt (struct parser *parser, int opt, char *val) } } else - /* A long option. We use shifts instead of masking for extracting - the user value in order to preserve the sign. */ - err = - group_parse (&parser->groups[group_key - 1], &parser->state, - (opt << GROUP_BITS) >> GROUP_BITS, - parser->opt_data.optarg); + /* A long option. Preserve the sign in the user key, without + invoking undefined behavior. Assume two's complement. */ + { + int user_key = + ((opt & (1 << (USER_BITS - 1))) ? ~USER_MASK : 0) | (opt & USER_MASK); + err = + group_parse (&parser->groups[group_key - 1], &parser->state, + user_key, parser->opt_data.optarg); + } if (err == EBADKEY) /* At least currently, an option not recognized is an error in the -- 2.47.2