From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sheng Yong Subject: Re: [RFC PATCH] mkfs.f2fs: avoid dumplicate extension Date: Sat, 28 Nov 2015 08:39:40 +0800 Message-ID: <5658F7CC.7030402@huawei.com> References: <1448643312-28861-1-git-send-email-shengyong1@huawei.com> <56585619.4050709@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1a2TYp-0003eX-Sk for linux-f2fs-devel@lists.sourceforge.net; Sat, 28 Nov 2015 00:40:19 +0000 Received: from szxga03-in.huawei.com ([119.145.14.66]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1a2TYk-0006tn-6U for linux-f2fs-devel@lists.sourceforge.net; Sat, 28 Nov 2015 00:40:19 +0000 In-Reply-To: <56585619.4050709@kernel.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Chao Yu Cc: jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net On 11/27/2015 9:09 PM, Chao Yu wrote: > Hi Sheng Yong, > > On 11/28/15 12:55 AM, Sheng Yong wrote: >> Before copying user specified extension to extension_list, check if it is >> already in the list. >> >> Signed-off-by: Sheng Yong >> --- >> mkfs/f2fs_format.c | 23 ++++++++++++++++++++++- >> 1 file changed, 22 insertions(+), 1 deletion(-) >> >> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c >> index 176bdea..b7ea19f 100644 >> --- a/mkfs/f2fs_format.c >> +++ b/mkfs/f2fs_format.c >> @@ -118,6 +118,26 @@ const char *media_ext_lists[] = { >> NULL >> }; >> >> +static int extension_exist(const char *name, const int len) > > bool is_extension_exist? > >> +{ >> + const char **extlist = media_ext_lists; >> + int name_len, min_len; >> + int ret; >> + >> + >> + while (*extlist) { >> + name_len = strlen(*extlist); >> + min_len = name_len < len ? name_len : len; >> + ret = strncmp(*extlist, name, min_len); > > How about using strcmp(*extlist, name)? It will return 0 only if the two strings > are the same. > Hi, Chao Yu Thanks for your reply. I was considering strcmp may have security issue. >> + >> + if (ret == 0 && name_len == len) >> + return 1; >> + extlist++; >> + } >> + >> + return 0; >> +} >> + >> static void configure_extension_list(void) >> { >> const char **extlist = media_ext_lists; >> @@ -144,7 +164,8 @@ static void configure_extension_list(void) >> ue = strtok(ext_str, ","); >> while (ue != NULL) { >> name_len = strlen(ue); > > We should verify the length of extension to avoid memcpy overflow. I will send a > patch for fixing. I agree. And I think we should make sure there is a '\0' at the end of each string in extension_list. > >> - memcpy(sb.extension_list[i++], ue, name_len); >> + if (!extension_exist(ue, name_len)) > > How do you think of comparing extension user defined with sb.extension_list? > In this way, duplication user defined can be avoided completely. Right. I'll send a v2 latter. thanks, Sheng > > Thanks, > >> + memcpy(sb.extension_list[i++], ue, name_len); >> ue = strtok(NULL, ","); >> if (i >= F2FS_MAX_EXTENSION) >> break; >> > > . > ------------------------------------------------------------------------------