Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Hi, In article <45676db9-d890-14a0-7743-f0340b7d1...@mail.com>, john doe wrote: >> [andy@xcp-dev dnsmasq (hosts-dirs *)]$ git diff --ignore-space-at-eol >> diff --git a/src/inotify.c b/src/inotify.c >> old mode 100644 >> new mode 100755 > > Is the change of the mode intentionel (from 644 to 755)? No. Probably a combination of my editor and it being accessed via Samba. The key change is to the content of inotify.c. Andy ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
On 2/11/2018 4:58 PM, Andy Hawkins wrote: Hi, In article , Andy Hawkins wrote: I could have a look at submitting a patch, but my editor is showing some very strange indentation of the source, so I suspect I have my tab settings incorrect. What is the standard setting for tabs on the dnasmasq source files? Here's an attempt at a patch. If it needs to be in a different format, then please let me know. The changes are minimal however, so applying the patch manually should be trivial. [andy@xcp-dev dnsmasq (hosts-dirs *)]$ git diff --ignore-space-at-eol diff --git a/src/inotify.c b/src/inotify.c old mode 100644 new mode 100755 Is the change of the mode intentionel (from 644 to 755)? index eda1d56..a655fe2 --- a/src/inotify.c +++ b/src/inotify.c @@ -235,8 +235,8 @@ int inotify_check(time_t now) /* ignore emacs backups and dotfiles */ if (in->len == 0 || - in->name[in->len - 1] == '~' || - (in->name[0] == '#' && in->name[in->len - 1] == '#') || + in->name[strlen(in->name) - 1] == '~' || + (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#') || in->name[0] == '.') continue; Hope that helps. Andy ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss -- John Doe ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Dominik,
I'm thinking you do not want to call
--
in->name[strlen(in->name)-1];
--
before testing for "if (in->len == 0"
Lonnie
On Feb 11, 2018, at 10:10 AM, Dominik Derigs wrote:
> Forgot to attach the proposed patch.
>
> Best,
> Dominik
>
>
> On 11.02.2018 17:02, Dominik Derigs wrote:
>> Hey Andy (and list),
>>
>> According to the inotify man page, the name buffer will always be
>> null-terminated. Furthermore, the name buffer seems to be allocated in
>> chunks of 16 bytes. I have not found an official confirmation for that.
>>
>> I the way to go would be: char lastchar = in->name[strlen(in->name)-1];
>>
>> I have extended your test code by the following two lines:
>>
>> if(in->name == NULL) continue;
>> printf("DD: strlen: %lu\n", strlen(in->name));
>> char lastchar = in->name[strlen(in->name)-1];
>> printf("DD: strlen last char: %c\n", lastchar);
>>
>> Here are results obtained with your + my debug output:
>>
>> For a short filename without ~
>>
>> ADH: len: 16
>> ADH: name: shortfilename
>> ADH: last char:
>> DD: strlen: 13
>> DD: strlen last char: e
>>
>> For a short filename with ~
>>
>> ADH: len: 16
>> ADH: name: shortfilename~
>> ADH: last char:
>> DD: strlen: 14
>> DD: strlen last char: ~
>>
>> For a long filename without ~
>>
>> ADH: len: 32
>> ADH: name: veryverylongfilename
>> ADH: last char:
>> DD: strlen: 20
>> DD: strlen last char: e
>>
>> For a long filename with ~
>>
>> ADH: len: 32
>> ADH: name: veryverylongfilename~
>> ADH: last char:
>> DD: strlen: 21
>> DD: strlen last char: ~
>>
>> Best regards,
>> Dominik
>>
>>
>> On 11.02.2018 12:57, Andy Hawkins wrote:
>>> Hi,
>>>
>>> In article ,
>>> Andy Hawkins wrote:
In inotify.c, around line 236 is the following code block:
/* ignore emacs backups and dotfiles */
if (in->len == 0 ||
in->name[in->len - 1] == '~' ||
(in->name[0] == '#' && in->name[in->len - 1] == '#') ||
in->name[0] == '.')
continue;
However, if I create a file called 'fred~' in the directory I've specified
using dhcp-hostsdir I still get an event in syslog that shows this file is
being processed:
Feb 11 11:14:34 xcp-gateway dnsmasq[1039]: inotify, new or changed file
/etc/dnsmasq/dhcp-hosts.d/fred~
>>> Ok, I've done some debugging. I added the following lines:
>>>
>>> my_syslog(LOG_INFO, "ADH: len: %d", in->len);
>>> my_syslog(LOG_INFO, "ADH: name: %s", in->name);
>>> my_syslog(LOG_INFO, "ADH: last char: %c", in->name[in->len - 1]);
>>>
>>> And I get the following output:
>>>
>>> dnsmasq: ADH: len: 16
>>> dnsmasq: ADH: name: fred4~
>>> dnsmasq: ADH: last char:
>>>
>>> So, it appears that the length in in->len is being interpreted correctly.
>>>
>>> According to the inotify man page:
>>>
>>> The len field counts all of the bytes in name, including the null
>>> bytes; the length of each inotify_event structure is thus
>>> sizeof(struct inotify_event)+len.
>>>
>>> So in fact, 'len' seems to be a fixed length, irrespective of the length of
>>> the file name in the 'name' field.
>>>
>>> It looks like the check should actually be something like:
>>>
>>> /* ignore emacs backups and dotfiles */
>>> if (in->len == 0 ||
>>> in->name[strlen(in->name) - 1] == '~' ||
>>> (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#') ||
>>> in->name[0] == '.')
>>>
>>> I guess you may need to check that there's a null in the name somewhere
>>> before using strlen, otherwise you might end up running off the end of the
>>> string. I don't know inotify well enough to know if there's guaranteed to be
>>> a null in there somewhere. The manpage does say that the name field is null
>>> terminated, but I don't know if that's guaranteed or not.
>>>
>>> I could have a look at submitting a patch, but my editor is showing some
>>> very strange indentation of the source, so I suspect I have my tab settings
>>> incorrect. What is the standard setting for tabs on the dnasmasq source
>>> files?
>>>
>>> Thanks
>>>
>>> Andy
>>>
>>>
>>> ___
>>> Dnsmasq-discuss mailing list
>>> Dnsmasq-discuss@lists.thekelleys.org.uk
>>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>
> ___
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> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
___
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Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Hi, In article , Andy Hawkins wrote: > I could have a look at submitting a patch, but my editor is showing some > very strange indentation of the source, so I suspect I have my tab settings > incorrect. What is the standard setting for tabs on the dnasmasq source > files? Here's an attempt at a patch. If it needs to be in a different format, then please let me know. The changes are minimal however, so applying the patch manually should be trivial. [andy@xcp-dev dnsmasq (hosts-dirs *)]$ git diff --ignore-space-at-eol diff --git a/src/inotify.c b/src/inotify.c old mode 100644 new mode 100755 index eda1d56..a655fe2 --- a/src/inotify.c +++ b/src/inotify.c @@ -235,8 +235,8 @@ int inotify_check(time_t now) /* ignore emacs backups and dotfiles */ if (in->len == 0 || - in->name[in->len - 1] == '~' || - (in->name[0] == '#' && in->name[in->len - 1] == '#') || + in->name[strlen(in->name) - 1] == '~' || + (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#') || in->name[0] == '.') continue; Hope that helps. Andy ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Forgot to attach the proposed patch.
Best,
Dominik
On 11.02.2018 17:02, Dominik Derigs wrote:
> Hey Andy (and list),
>
> According to the inotify man page, the name buffer will always be
> null-terminated. Furthermore, the name buffer seems to be allocated in
> chunks of 16 bytes. I have not found an official confirmation for that.
>
> I the way to go would be: char lastchar = in->name[strlen(in->name)-1];
>
> I have extended your test code by the following two lines:
>
> if(in->name == NULL) continue;
> printf("DD: strlen: %lu\n", strlen(in->name));
> char lastchar = in->name[strlen(in->name)-1];
> printf("DD: strlen last char: %c\n", lastchar);
>
> Here are results obtained with your + my debug output:
>
> For a short filename without ~
>
> ADH: len: 16
> ADH: name: shortfilename
> ADH: last char:
> DD: strlen: 13
> DD: strlen last char: e
>
> For a short filename with ~
>
> ADH: len: 16
> ADH: name: shortfilename~
> ADH: last char:
> DD: strlen: 14
> DD: strlen last char: ~
>
> For a long filename without ~
>
> ADH: len: 32
> ADH: name: veryverylongfilename
> ADH: last char:
> DD: strlen: 20
> DD: strlen last char: e
>
> For a long filename with ~
>
> ADH: len: 32
> ADH: name: veryverylongfilename~
> ADH: last char:
> DD: strlen: 21
> DD: strlen last char: ~
>
> Best regards,
> Dominik
>
>
> On 11.02.2018 12:57, Andy Hawkins wrote:
>> Hi,
>>
>> In article ,
>>Andy Hawkins wrote:
>>> In inotify.c, around line 236 is the following code block:
>>>
>>> /* ignore emacs backups and dotfiles */
>>> if (in->len == 0 ||
>>> in->name[in->len - 1] == '~' ||
>>> (in->name[0] == '#' && in->name[in->len - 1] == '#') ||
>>> in->name[0] == '.')
>>> continue;
>>>
>>> However, if I create a file called 'fred~' in the directory I've specified
>>> using dhcp-hostsdir I still get an event in syslog that shows this file is
>>> being processed:
>>>
>>> Feb 11 11:14:34 xcp-gateway dnsmasq[1039]: inotify, new or changed file
>>> /etc/dnsmasq/dhcp-hosts.d/fred~
>> Ok, I've done some debugging. I added the following lines:
>>
>> my_syslog(LOG_INFO, "ADH: len: %d", in->len);
>> my_syslog(LOG_INFO, "ADH: name: %s", in->name);
>> my_syslog(LOG_INFO, "ADH: last char: %c", in->name[in->len - 1]);
>>
>> And I get the following output:
>>
>> dnsmasq: ADH: len: 16
>> dnsmasq: ADH: name: fred4~
>> dnsmasq: ADH: last char:
>>
>> So, it appears that the length in in->len is being interpreted correctly.
>>
>> According to the inotify man page:
>>
>>The len field counts all of the bytes in name, including the null
>>bytes; the length of each inotify_event structure is thus
>>sizeof(struct inotify_event)+len.
>>
>> So in fact, 'len' seems to be a fixed length, irrespective of the length of
>> the file name in the 'name' field.
>>
>> It looks like the check should actually be something like:
>>
>> /* ignore emacs backups and dotfiles */
>> if (in->len == 0 ||
>> in->name[strlen(in->name) - 1] == '~' ||
>> (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#')
>> ||
>> in->name[0] == '.')
>>
>> I guess you may need to check that there's a null in the name somewhere
>> before using strlen, otherwise you might end up running off the end of the
>> string. I don't know inotify well enough to know if there's guaranteed to be
>> a null in there somewhere. The manpage does say that the name field is null
>> terminated, but I don't know if that's guaranteed or not.
>>
>> I could have a look at submitting a patch, but my editor is showing some
>> very strange indentation of the source, so I suspect I have my tab settings
>> incorrect. What is the standard setting for tabs on the dnasmasq source
>> files?
>>
>> Thanks
>>
>> Andy
>>
>>
>> ___
>> Dnsmasq-discuss mailing list
>> Dnsmasq-discuss@lists.thekelleys.org.uk
>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
diff --git a/inotify.c b/inotify.c
index b5a17dd..51d13be 100644
--- a/inotify.c
+++ b/inotify.c
@@ -234,9 +234,10 @@ int inotify_check(time_t now)
hit = 1;
/* ignore emacs backups and dotfiles */
+ char lastchar = in->name[strlen(in->name)-1];
if (in->len == 0 ||
- in->name[in->len - 1] == '~' ||
- (in->name[0] == '#' && in->name[in->len - 1] == '#') ||
+ lastchar == '~' ||
+ (in->name[0] == '#' && lastchar == '#') ||
in->name[0] == '.')
continue;
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Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Hey Andy (and list),
According to the inotify man page, the name buffer will always be
null-terminated. Furthermore, the name buffer seems to be allocated in
chunks of 16 bytes. I have not found an official confirmation for that.
I the way to go would be: char lastchar = in->name[strlen(in->name)-1];
I have extended your test code by the following two lines:
if(in->name == NULL) continue;
printf("DD: strlen: %lu\n", strlen(in->name));
char lastchar = in->name[strlen(in->name)-1];
printf("DD: strlen last char: %c\n", lastchar);
Here are results obtained with your + my debug output:
For a short filename without ~
ADH: len: 16
ADH: name: shortfilename
ADH: last char:
DD: strlen: 13
DD: strlen last char: e
For a short filename with ~
ADH: len: 16
ADH: name: shortfilename~
ADH: last char:
DD: strlen: 14
DD: strlen last char: ~
For a long filename without ~
ADH: len: 32
ADH: name: veryverylongfilename
ADH: last char:
DD: strlen: 20
DD: strlen last char: e
For a long filename with ~
ADH: len: 32
ADH: name: veryverylongfilename~
ADH: last char:
DD: strlen: 21
DD: strlen last char: ~
Best regards,
Dominik
On 11.02.2018 12:57, Andy Hawkins wrote:
> Hi,
>
> In article ,
>Andy Hawkins wrote:
>> In inotify.c, around line 236 is the following code block:
>>
>>/* ignore emacs backups and dotfiles */
>>if (in->len == 0 ||
>>in->name[in->len - 1] == '~' ||
>>(in->name[0] == '#' && in->name[in->len - 1] == '#') ||
>>in->name[0] == '.')
>> continue;
>>
>> However, if I create a file called 'fred~' in the directory I've specified
>> using dhcp-hostsdir I still get an event in syslog that shows this file is
>> being processed:
>>
>> Feb 11 11:14:34 xcp-gateway dnsmasq[1039]: inotify, new or changed file
>> /etc/dnsmasq/dhcp-hosts.d/fred~
> Ok, I've done some debugging. I added the following lines:
>
> my_syslog(LOG_INFO, "ADH: len: %d", in->len);
> my_syslog(LOG_INFO, "ADH: name: %s", in->name);
> my_syslog(LOG_INFO, "ADH: last char: %c", in->name[in->len - 1]);
>
> And I get the following output:
>
> dnsmasq: ADH: len: 16
> dnsmasq: ADH: name: fred4~
> dnsmasq: ADH: last char:
>
> So, it appears that the length in in->len is being interpreted correctly.
>
> According to the inotify man page:
>
>The len field counts all of the bytes in name, including the null
>bytes; the length of each inotify_event structure is thus
>sizeof(struct inotify_event)+len.
>
> So in fact, 'len' seems to be a fixed length, irrespective of the length of
> the file name in the 'name' field.
>
> It looks like the check should actually be something like:
>
> /* ignore emacs backups and dotfiles */
> if (in->len == 0 ||
> in->name[strlen(in->name) - 1] == '~' ||
> (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#') ||
> in->name[0] == '.')
>
> I guess you may need to check that there's a null in the name somewhere
> before using strlen, otherwise you might end up running off the end of the
> string. I don't know inotify well enough to know if there's guaranteed to be
> a null in there somewhere. The manpage does say that the name field is null
> terminated, but I don't know if that's guaranteed or not.
>
> I could have a look at submitting a patch, but my editor is showing some
> very strange indentation of the source, so I suspect I have my tab settings
> incorrect. What is the standard setting for tabs on the dnasmasq source
> files?
>
> Thanks
>
> Andy
>
>
> ___
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss@lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
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Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Hi, In article , Andy Hawkins wrote: > In inotify.c, around line 236 is the following code block: > > /* ignore emacs backups and dotfiles */ > if (in->len == 0 || > in->name[in->len - 1] == '~' || > (in->name[0] == '#' && in->name[in->len - 1] == '#') || > in->name[0] == '.') > continue; > > However, if I create a file called 'fred~' in the directory I've specified > using dhcp-hostsdir I still get an event in syslog that shows this file is > being processed: > > Feb 11 11:14:34 xcp-gateway dnsmasq[1039]: inotify, new or changed file > /etc/dnsmasq/dhcp-hosts.d/fred~ Ok, I've done some debugging. I added the following lines: my_syslog(LOG_INFO, "ADH: len: %d", in->len); my_syslog(LOG_INFO, "ADH: name: %s", in->name); my_syslog(LOG_INFO, "ADH: last char: %c", in->name[in->len - 1]); And I get the following output: dnsmasq: ADH: len: 16 dnsmasq: ADH: name: fred4~ dnsmasq: ADH: last char: So, it appears that the length in in->len is being interpreted correctly. According to the inotify man page: The len field counts all of the bytes in name, including the null bytes; the length of each inotify_event structure is thus sizeof(struct inotify_event)+len. So in fact, 'len' seems to be a fixed length, irrespective of the length of the file name in the 'name' field. It looks like the check should actually be something like: /* ignore emacs backups and dotfiles */ if (in->len == 0 || in->name[strlen(in->name) - 1] == '~' || (in->name[0] == '#' && in->name[strlen(in->name) - 1] == '#') || in->name[0] == '.') I guess you may need to check that there's a null in the name somewhere before using strlen, otherwise you might end up running off the end of the string. I don't know inotify well enough to know if there's guaranteed to be a null in there somewhere. The manpage does say that the name field is null terminated, but I don't know if that's guaranteed or not. I could have a look at submitting a patch, but my editor is showing some very strange indentation of the source, so I suspect I have my tab settings incorrect. What is the standard setting for tabs on the dnasmasq source files? Thanks Andy ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
Hi, In article <20180211083655.gy21...@gpm.stappers.nl>, Geert Stappers wrote: > I do read that statement as 80% of needed source code already present. > Craft the missing source code into a patch, posted to here > and see what happens. I decided to do exactly that, and started looking at the code. It looks like it should already be ignoring files that end in a ~. However, on my version it's not. In inotify.c, around line 236 is the following code block: /* ignore emacs backups and dotfiles */ if (in->len == 0 || in->name[in->len - 1] == '~' || (in->name[0] == '#' && in->name[in->len - 1] == '#') || in->name[0] == '.') continue; However, if I create a file called 'fred~' in the directory I've specified using dhcp-hostsdir I still get an event in syslog that shows this file is being processed: Feb 11 11:14:34 xcp-gateway dnsmasq[1039]: inotify, new or changed file /etc/dnsmasq/dhcp-hosts.d/fred~ This suggest that either I'm reading the code incorrectly (perfectly possible!) or that the code isn't doing what it is supposed to do? Which is it? Anyone? Thanks Andy ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Extension to hosts-dir and dhcohosts-dir
On Thu, Feb 08, 2018 at 09:11:43PM -, Andy Hawkins wrote: > In article <20180208164432.GA97242@wopr>, Kurt H Maier wrote: > > You should fix the editor; that behavior is dangerous for other reasons, > > similar to the ones outlined here: > > http://openwall.com/lists/oss-security/2017/11/27/2 > > I take your point. However, given that the facility is available for config > files, I don't see any reason why it shouldn't be extended to other > directories that contain files that are designed to be modified while > dnsmasq is running. I do read that statement as 80% of needed source code already present. Craft the missing source code into a patch, posted to here and see what happens. Groeten Geert Stappers -- Leven en laten leven ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
