[PATCH 1/1] ip: fix igmp parsing when iface is long

[PATCH 1/1] ip: fix igmp parsing when iface is long

[Petr Vorel]

Entries with long vhost names in /proc/net/igmp have no whitespace
between name and colon, so sscanf() adds it to vhost and
'ip maddr show iface' doesn't include inet result.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
 ip/ipmaddr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c
index 22eb407..4f726fd 100644
--- a/ip/ipmaddr.c
+++ b/ip/ipmaddr.c
@@ -136,13 +136,17 @@ static void read_igmp(struct ma_info **result_p)
 
 	while (fgets(buf, sizeof(buf), fp)) {
 		struct ma_info *ma;
+		size_t len;
 
 		if (buf[0] != '\t') {
 			sscanf(buf, "%d%s", &m.index, m.name);
+			len = strlen(m.name);
+			if (m.name[len - 1] == ':')
+				len--;
 			continue;
 		}
 
-		if (filter.dev && strcmp(filter.dev, m.name))
+		if (filter.dev && strncmp(filter.dev, m.name, len))
 			continue;
 
 		sscanf(buf, "%08x%d", (__u32 *)&m.addr.data, &m.users);
-- 
2.11.0

Re: [PATCH 1/1] ip: fix igmp parsing when iface is long

[Petr Vorel]

Hi,

> Entries with long vhost names in /proc/net/igmp have no whitespace
> between name and colon, so sscanf() adds it to vhost and
> 'ip maddr show iface' doesn't include inet result.

Bug was also reported to bugzilla (https://bugzilla.kernel.org/show_bug.cgi?id=192741),
with updated comment in the patch.


Kind regards,
Petr

Re: [PATCH 1/1] ip: fix igmp parsing when iface is long

[Stephen Hemminger]

On Tue, 17 Jan 2017 09:08:09 +0100
Petr Vorel <pvorel@suse.cz> wrote:

> Hi,
> 
> > Entries with long vhost names in /proc/net/igmp have no whitespace
> > between name and colon, so sscanf() adds it to vhost and
> > 'ip maddr show iface' doesn't include inet result.  
> 
> Bug was also reported to bugzilla (https://bugzilla.kernel.org/show_bug.cgi?id=192741),
> with updated comment in the patch.
> 
> 
> Kind regards,
> Petr

Kernel bugzilla is irrelevant and ignored by network developers.

Re: [PATCH 1/1] ip: fix igmp parsing when iface is long

[Stephen Hemminger]

On Tue, 17 Jan 2017 00:25:50 +0100
Petr Vorel <pvorel@suse.cz> wrote:

> Entries with long vhost names in /proc/net/igmp have no whitespace
> between name and colon, so sscanf() adds it to vhost and
> 'ip maddr show iface' doesn't include inet result.
> 
> Signed-off-by: Petr Vorel <pvorel@suse.cz>

Looks good, applied