From da5b32fb4656ab69fe1156eb7e36c7c961839e8a Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 8 Jun 2022 13:45:13 +0200 Subject: [PATCH] extensions: string: Review parse_string() function * Compare against sizeof(info->pattern) which is more clear than having to know that this buffer is of size XT_STRING_MAX_PATTERN_SIZE * Invert the check and error early to reduce indenting * Pass info->patlen to memcpy() to avoid reading past end of 's' Signed-off-by: Phil Sutter --- extensions/libxt_string.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/extensions/libxt_string.c +++ b/extensions/libxt_string.c @@ -78,14 +78,13 @@ static void string_init(struct xt_entry_ static void parse_string(const char *s, struct xt_string_info *info) -{ +{ /* xt_string does not need \0 at the end of the pattern */ - if (strlen(s) <= XT_STRING_MAX_PATTERN_SIZE) { - memcpy(info->pattern, s, XT_STRING_MAX_PATTERN_SIZE); - info->patlen = strnlen(s, XT_STRING_MAX_PATTERN_SIZE); - return; - } - xtables_error(PARAMETER_PROBLEM, "STRING too long \"%s\"", s); + if (strlen(s) > sizeof(info->pattern)) + xtables_error(PARAMETER_PROBLEM, "STRING too long \"%s\"", s); + + info->patlen = strnlen(s, sizeof(info->pattern)); + memcpy(info->pattern, s, info->patlen); } static void