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| author | Jiri Bohac <jbohac@suse.cz> | 2021-03-18 04:42:53 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-18 14:40:53 -0700 |
| commit | 6c015a2256801597fadcbc11d287774c9c512fa5 (patch) | |
| tree | 1edd60c501e1d98ce8dca9924bf18d4428b7c5be | |
| parent | 600cc3c9c62defd920da07bc585eb739247bb732 (diff) | |
| download | linux-6c015a2256801597fadcbc11d287774c9c512fa5.tar.bz2 | |
net: check all name nodes in __dev_alloc_name
__dev_alloc_name(), when supplied with a name containing '%d',
will search for the first available device number to generate a
unique device name.
Since commit ff92741270bf8b6e78aa885f166b68c7a67ab13a ("net:
introduce name_node struct to be used in hashlist") network
devices may have alternate names. __dev_alloc_name() does take
these alternate names into account, possibly generating a name
that is already taken and failing with -ENFILE as a result.
This demonstrates the bug:
# rmmod dummy 2>/dev/null
# ip link property add dev lo altname dummy0
# modprobe dummy numdummies=1
modprobe: ERROR: could not insert 'dummy': Too many open files in system
Instead of creating a device named dummy1, modprobe fails.
Fix this by checking all the names in the d->name_node list, not just d->name.
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Fixes: ff92741270bf ("net: introduce name_node struct to be used in hashlist")
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/dev.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index bb568f7cb81b..0f72ff5d34ba 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1184,6 +1184,18 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) return -ENOMEM; for_each_netdev(net, d) { + struct netdev_name_node *name_node; + list_for_each_entry(name_node, &d->name_node->list, list) { + if (!sscanf(name_node->name, name, &i)) + continue; + if (i < 0 || i >= max_netdevices) + continue; + + /* avoid cases where sscanf is not exact inverse of printf */ + snprintf(buf, IFNAMSIZ, name, i); + if (!strncmp(buf, name_node->name, IFNAMSIZ)) + set_bit(i, inuse); + } if (!sscanf(d->name, name, &i)) continue; if (i < 0 || i >= max_netdevices) |