Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755592Ab2HTR3r (ORCPT ); Mon, 20 Aug 2012 13:29:47 -0400 Received: from mx.meyering.net ([88.168.87.75]:44788 "EHLO hx.meyering.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753889Ab2HTR3a (ORCPT ); Mon, 20 Aug 2012 13:29:30 -0400 X-Greylist: delayed 1926 seconds by postgrey-1.27 at vger.kernel.org; Mon, 20 Aug 2012 13:29:30 EDT From: Jim Meyering To: linux-kernel@vger.kernel.org Cc: Jim Meyering , Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org Subject: [PATCH] cifs: remove misleading strncpy: each name has length < 16 Date: Mon, 20 Aug 2012 18:55:24 +0200 Message-Id: <1345481724-30108-6-git-send-email-jim@meyering.net> X-Mailer: git-send-email 1.7.12 In-Reply-To: <1345481724-30108-1-git-send-email-jim@meyering.net> References: <1345481724-30108-1-git-send-email-jim@meyering.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1601 Lines: 42 From: Jim Meyering Each of the protocols[i].name strings (statically declared above) has length less than 16, so this use of strncpy is misleading: strncpy(pSMB->DialectsArray+count, protocols[i].name, 16); Besides, if a new name were added with length N >= 16, the existing strncpy-using code would be buggy, creating a ->DialectsArray buffer containing N-16+1 unset bytes where the NUL terminator should have been. Instead, traverse the name only once go get its length, use a BUG_ON assertion to enforce the length restriction and use memcpy to perform the copy. Signed-off-by: Jim Meyering --- fs/cifs/cifssmb.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c index 074923c..16a9018 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -441,8 +441,10 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses) count = 0; for (i = 0; i < CIFS_NUM_PROT; i++) { - strncpy(pSMB->DialectsArray+count, protocols[i].name, 16); - count += strlen(protocols[i].name) + 1; + size_t len = strlen(protocols[i].name); + BUG_ON(len >= 16); + memcpy(pSMB->DialectsArray+count, protocols[i].name, len + 1); + count += len + 1; /* null at end of source and target buffers anyway */ } inc_rfc1001_len(pSMB, count); -- 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/