[PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Isaac Boukris]

Abstract unix domain socket may embed null characters,
these should be translated to '@' when printed by ss the
same way the null prefix is currently being translated.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
---
 misc/ss.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/misc/ss.c b/misc/ss.c
index dd77b81..0e28998 100644
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -2895,7 +2895,9 @@ static int unix_show_sock(const struct sockaddr_nl *addr, struct nlmsghdr *nlh,
 		memcpy(name, RTA_DATA(tb[UNIX_DIAG_NAME]), len);
 		name[len] = '\0';
 		if (name[0] == '\0')
-			name[0] = '@';
+			for (int i = 0; i < len; i++)
+				if (name[i] == '\0')
+					name[i] = '@';
 		stat.name = &name[0];
 		memcpy(stat.local.data, &stat.name, sizeof(stat.name));
 	}
-- 
2.7.4

[PATCH] unix: escape all null bytes in abstract unix domain socket

[Isaac Boukris]

Abstract unix domain socket may embed null characters,
these should be translated to '@' when printed out to
proc the same way the null prefix is currently being
translated.

This helps for tools such as netstat, lsof and the proc
based implementation in ss to show all the significant
bytes of the name (instead of getting cut at the first
null occurrence).

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
---
 net/unix/af_unix.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 145082e..9250b03 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2805,14 +2805,19 @@ static int unix_seq_show(struct seq_file *seq, void *v)
 
 			i = 0;
 			len = u->addr->len - sizeof(short);
-			if (!UNIX_ABSTRACT(s))
+			if (!UNIX_ABSTRACT(s)) {
 				len--;
-			else {
+				for ( ; i < len; i++)
+					seq_putc(seq,
+						 u->addr->name->sun_path[i]);
+			} else {
 				seq_putc(seq, '@');
 				i++;
+				for ( ; i < len; i++)
+					seq_putc(seq,
+						 u->addr->name->sun_path[i] ?:
+						 '@');
 			}
-			for ( ; i < len; i++)
-				seq_putc(seq, u->addr->name->sun_path[i]);
 		}
 		unix_state_unlock(s);
 		seq_putc(seq, '\n');
-- 
2.7.4

Re: [PATCH] unix: escape all null bytes in abstract unix domain socket

[David Miller]

From: Isaac Boukris <iboukris@gmail.com>
Date: Sat, 29 Oct 2016 22:20:20 +0300

> Abstract unix domain socket may embed null characters,
> these should be translated to '@' when printed out to
> proc the same way the null prefix is currently being
> translated.
> 
> This helps for tools such as netstat, lsof and the proc
> based implementation in ss to show all the significant
> bytes of the name (instead of getting cut at the first
> null occurrence).
> 
> Signed-off-by: Isaac Boukris <iboukris@gmail.com>
 ...
> @@ -2805,14 +2805,19 @@ static int unix_seq_show(struct seq_file *seq, void *v)
>  
>  			i = 0;
>  			len = u->addr->len - sizeof(short);
> -			if (!UNIX_ABSTRACT(s))
> +			if (!UNIX_ABSTRACT(s)) {
>  				len--;
> -			else {
> +				for ( ; i < len; i++)
> +					seq_putc(seq,
> +						 u->addr->name->sun_path[i]);
> +			} else {
>  				seq_putc(seq, '@');
>  				i++;
> +				for ( ; i < len; i++)
> +					seq_putc(seq,
> +						 u->addr->name->sun_path[i] ?:
> +						 '@');
>  			}
> -			for ( ; i < len; i++)
> -				seq_putc(seq, u->addr->name->sun_path[i]);

I think this patch is simpler if you just do the "@" translation
unconditionally, if it'll never trigger for the !UNIX_ABSTRACT case
that is perfectly fine.

Re: [PATCH] unix: escape all null bytes in abstract unix domain socket

[Isaac Boukris]

Hi David, thanks for looking at it.

On Mon, Oct 31, 2016 at 9:31 PM, David Miller <davem@davemloft.net> wrote:
> From: Isaac Boukris <iboukris@gmail.com>
> Date: Sat, 29 Oct 2016 22:20:20 +0300
>
>> Abstract unix domain socket may embed null characters,
>> these should be translated to '@' when printed out to
>> proc the same way the null prefix is currently being
>> translated.
>>
>> This helps for tools such as netstat, lsof and the proc
>> based implementation in ss to show all the significant
>> bytes of the name (instead of getting cut at the first
>> null occurrence).
>>
>> Signed-off-by: Isaac Boukris <iboukris@gmail.com>
>  ...
>> @@ -2805,14 +2805,19 @@ static int unix_seq_show(struct seq_file *seq, void *v)
>>
>>                       i = 0;
>>                       len = u->addr->len - sizeof(short);
>> -                     if (!UNIX_ABSTRACT(s))
>> +                     if (!UNIX_ABSTRACT(s)) {
>>                               len--;
>> -                     else {
>> +                             for ( ; i < len; i++)
>> +                                     seq_putc(seq,
>> +                                              u->addr->name->sun_path[i]);
>> +                     } else {
>>                               seq_putc(seq, '@');
>>                               i++;
>> +                             for ( ; i < len; i++)
>> +                                     seq_putc(seq,
>> +                                              u->addr->name->sun_path[i] ?:
>> +                                              '@');
>>                       }
>> -                     for ( ; i < len; i++)
>> -                             seq_putc(seq, u->addr->name->sun_path[i]);
>
> I think this patch is simpler if you just do the "@" translation
> unconditionally, if it'll never trigger for the !UNIX_ABSTRACT case
> that is perfectly fine.

I've sent an updated patch.
Logically now, the 'else' block just above could be removed, but it
isn't obvious from the code that 'sun_path[0] == 0' so I left it as
is.

Re: [PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Stephen Hemminger]

On Sat, 29 Oct 2016 22:20:19 +0300
Isaac Boukris <iboukris@gmail.com> wrote:

> Abstract unix domain socket may embed null characters,
> these should be translated to '@' when printed by ss the
> same way the null prefix is currently being translated.
> 
> Signed-off-by: Isaac Boukris <iboukris@gmail.com>

Applied

Re: [PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Eric Dumazet]

On Sat, 2016-11-12 at 10:17 +0300, Stephen Hemminger wrote:
> On Sat, 29 Oct 2016 22:20:19 +0300
> Isaac Boukris <iboukris@gmail.com> wrote:
> 
> > Abstract unix domain socket may embed null characters,
> > these should be translated to '@' when printed by ss the
> > same way the null prefix is currently being translated.
> > 
> > Signed-off-by: Isaac Boukris <iboukris@gmail.com>
> 
> Applied

Probably not a good idea to have :

                       for (int i = 0; i < len; i++)
                               if (name[i] == '\0')
                                       name[i] = '@';

ss.c: In function 'unix_show_sock':
ss.c:3128:4: error: 'for' loop initial declarations are only allowed in C99 mode
ss.c:3128:4: note: use option -std=c99 or -std=gnu99 to compile your code
make[1]: *** [ss.o] Error 1

Re: [PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Stephen Hemminger]

On Fri, 02 Dec 2016 10:59:56 -0800
Eric Dumazet <eric.dumazet@gmail.com> wrote:

> On Sat, 2016-11-12 at 10:17 +0300, Stephen Hemminger wrote:
> > On Sat, 29 Oct 2016 22:20:19 +0300
> > Isaac Boukris <iboukris@gmail.com> wrote:
> >   
> > > Abstract unix domain socket may embed null characters,
> > > these should be translated to '@' when printed by ss the
> > > same way the null prefix is currently being translated.
> > > 
> > > Signed-off-by: Isaac Boukris <iboukris@gmail.com>  
> > 
> > Applied  
> 
> Probably not a good idea to have :
> 
>                        for (int i = 0; i < len; i++)
>                                if (name[i] == '\0')
>                                        name[i] = '@';
> 
> ss.c: In function 'unix_show_sock':
> ss.c:3128:4: error: 'for' loop initial declarations are only allowed in C99 mode
> ss.c:3128:4: note: use option -std=c99 or -std=gnu99 to compile your code
> make[1]: *** [ss.o] Error 1
> 
> 
> 

Thanks, fixed by patch from Simon

Re: [PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Eric Dumazet]

On Fri, 2016-12-02 at 15:18 -0800, Stephen Hemminger wrote:
>                                     name[i] = '@';
> > 
> > ss.c: In function 'unix_show_sock':
> > ss.c:3128:4: error: 'for' loop initial declarations are only allowed in C99 mode
> > ss.c:3128:4: note: use option -std=c99 or -std=gnu99 to compile your code
> > make[1]: *** [ss.o] Error 1
> > 
> > 
> > 
> 
> Thanks, fixed by patch from Simon

Right, thanks !

Re: [PATCH] iproute2: ss: escape all null bytes in abstract unix domain socket

[Isaac Boukris]

On Sat, Dec 3, 2016 at 1:24 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Fri, 2016-12-02 at 15:18 -0800, Stephen Hemminger wrote:
>>                                     name[i] = '@';
>> >
>> > ss.c: In function 'unix_show_sock':
>> > ss.c:3128:4: error: 'for' loop initial declarations are only allowed in C99 mode
>> > ss.c:3128:4: note: use option -std=c99 or -std=gnu99 to compile your code
>> > make[1]: *** [ss.o] Error 1
>> >
>> >
>> >
>>
>> Thanks, fixed by patch from Simon
>
> Right, thanks !


Thanks for notifying me. Sorry for the bug and thanks for the fix!