From mboxrd@z Thu Jan 1 00:00:00 1970 From: Allain Legacy Subject: [PATCH v5 4/6] cfgfile: use strnlen to constrain memchr search Date: Fri, 31 Mar 2017 09:52:01 -0400 Message-ID: <20170331135203.117461-5-allain.legacy@windriver.com> References: <20170330185407.61220-1-allain.legacy@windriver.com> <20170331135203.117461-1-allain.legacy@windriver.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , To: , Return-path: Received: from mail.windriver.com (mail.windriver.com [147.11.1.11]) by dpdk.org (Postfix) with ESMTP id 562602BE9 for ; Fri, 31 Mar 2017 15:52:30 +0200 (CEST) In-Reply-To: <20170331135203.117461-1-allain.legacy@windriver.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" The call to memchr() uses the absolute length of the string buffer instead of the actual length of the string returned by fgets(). This causes the search to go beyond the '\n' character and find ';' characters in random garbage on the stack. This then causes the 'len' variable to be updated and the subsequent search for the '=' character to potentially find one beyond the first newline character. Since this bug relies on ';' and '=' characters appearing in random places in the 'buffer' variable it is intermittently reproducible at best. Signed-off-by: Allain Legacy Acked-by: Cristian Dumitrescu --- lib/librte_cfgfile/rte_cfgfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/librte_cfgfile/rte_cfgfile.c b/lib/librte_cfgfile/rte_cfgfile.c index 63e34bbb0..e4a3885b7 100644 --- a/lib/librte_cfgfile/rte_cfgfile.c +++ b/lib/librte_cfgfile/rte_cfgfile.c @@ -191,7 +191,7 @@ rte_cfgfile_load_with_params(const char *filename, int flags, "Check if line too long\n", lineno); goto error1; } - pos = memchr(buffer, params->comment_character, sizeof(buffer)); + pos = memchr(buffer, params->comment_character, len); if (pos != NULL) { *pos = '\0'; len = pos - buffer; -- 2.12.1