From: Ferruh Yigit <ferruh.yigit@intel.com>
To: "Chaitanya Babu, TalluriX" <tallurix.chaitanya.babu@intel.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Pattan, Reshma" <reshma.pattan@intel.com>,
"Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com>,
"Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH v2] lib/cfgfile: replace strcat with strlcat
Date: Wed, 27 Mar 2019 11:37:50 +0000 [thread overview]
Message-ID: <d5f01da4-b9a7-67f1-860a-dcd7c354da40@intel.com> (raw)
In-Reply-To: <761FB0F2AB727F4FA9CE98D18810B0151B1F18AA@BGSMSX103.gar.corp.intel.com>
On 3/26/2019 10:04 AM, Chaitanya Babu, TalluriX wrote:
> Hi
>
>> -----Original Message-----
>> From: Yigit, Ferruh
>> Sent: Friday, March 8, 2019 11:01 PM
>> To: Richardson, Bruce <bruce.richardson@intel.com>; Chaitanya Babu, TalluriX
>> <tallurix.chaitanya.babu@intel.com>
>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>;
>> Parthasarathy, JananeeX M <jananeex.m.parthasarathy@intel.com>;
>> Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; stable@dpdk.org
>> Subject: Re: [PATCH v2] lib/cfgfile: replace strcat with strlcat
>>
>> On 3/8/2019 2:02 PM, Bruce Richardson wrote:
>>> On Fri, Mar 08, 2019 at 12:45:50PM +0000, Chaitanya Babu Talluri wrote:
>>>> Replace strcat with strlcat to avoid buffer overflow.
>>>>
>>>> Fixes: a6a47ac9c2 ("cfgfile: rework load function")
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Chaitanya Babu Talluri
>>>> <tallurix.chaitanya.babu@intel.com>
>>>> ---
>>>> v2: Instead of strcat, used strlcat.
>>>> ---
>>>> lib/librte_cfgfile/rte_cfgfile.c | 4 +++-
>>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/lib/librte_cfgfile/rte_cfgfile.c
>>>> b/lib/librte_cfgfile/rte_cfgfile.c
>>>> index 7d8c941ea..3296bb6f8 100644
>>>> --- a/lib/librte_cfgfile/rte_cfgfile.c
>>>> +++ b/lib/librte_cfgfile/rte_cfgfile.c
>>>> @@ -8,6 +8,7 @@
>>>> #include <ctype.h>
>>>> #include <errno.h>
>>>> #include <rte_common.h>
>>>> +#include <rte_string_fns.h>
>>>>
>>>> #include "rte_cfgfile.h"
>>>>
>>>> @@ -224,10 +225,11 @@ rte_cfgfile_load_with_params(const char
>> *filename, int flags,
>>>> _strip(split[1], strlen(split[1]));
>>>> char *end = memchr(split[1], '\\', strlen(split[1]));
>>>>
>>>> + size_t split_len = strlen(split[1]) + 1;
>>>> while (end != NULL) {
>>>> if (*(end+1) == params->comment_character)
>> {
>>>> *end = '\0';
>>>> - strcat(split[1], end+1);
>>>> + strlcat(split[1], end+1, split_len);
>>>
>>> I don't think this will do what you want. Remember that strlcat takes
>>> the total length of the buffer, which means that if split_len is set
>>> to the current length (as you do before the while statement), then
>>> passing that as the length parameter will cause strlcat to do nothing,
>>> since it sees the buffer as already full.
>>
>> The logic doesn't lengthen the 'split[1]' content, indeed it reduces the initial
>> size although it uses string concatenation, that is why it should be OK to use
>> 'split_len' here.
>>
>> What code does is, it finds specific char in 'split' buffer and removes it by
>> shifting remaining chars one byte to the left. So it shouldn't pass the initial size
>> of the buffer.
>>
>> There is a overlapping strings concern, which 'strcat' & 'strlcat' don't support,
>> but I guess it is OK here since we are sure that strings are separated by a
>> NULL, so where a char read and written should be different although overall
>> dst and src buffers overlap.
>
> Yes, although the same string is manipulated the split string (*end = '\0') is separated with NULL.
> Strlcat works fine here and expected concatenation is happening.
> If there are no further comments request for ACK please.
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>
next prev parent reply other threads:[~2019-03-27 11:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 9:30 [dpdk-stable] [PATCH] lib: fix strcat with equivalent logic Chaitanya Babu Talluri
2019-02-14 14:00 ` [dpdk-stable] [dpdk-dev] " Bruce Richardson
2019-03-08 12:45 ` [dpdk-stable] [PATCH v2] lib/cfgfile: replace strcat with strlcat Chaitanya Babu Talluri
2019-03-08 14:02 ` Bruce Richardson
2019-03-08 17:30 ` Ferruh Yigit
[not found] ` <761FB0F2AB727F4FA9CE98D18810B0151B1F18AA@BGSMSX103.gar.corp.intel.com>
2019-03-27 11:37 ` Ferruh Yigit [this message]
2019-04-05 12:53 ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d5f01da4-b9a7-67f1-860a-dcd7c354da40@intel.com \
--to=ferruh.yigit@intel.com \
--cc=bruce.richardson@intel.com \
--cc=cristian.dumitrescu@intel.com \
--cc=dev@dpdk.org \
--cc=jananeex.m.parthasarathy@intel.com \
--cc=reshma.pattan@intel.com \
--cc=stable@dpdk.org \
--cc=tallurix.chaitanya.babu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).