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| author | Jiri Bohac <jbohac@suse.cz> | 2021-03-18 06:42:53 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-30 15:32:02 +0300 |
| commit | 943e1583bf8a5cbcedfc4a00d92d8aac9e7e436d (patch) | |
| tree | 4c207eaf63e39909187ccb84b98176cf394171a7 /net | |
| parent | 748a158359d7c442ded1f29efe49975deec7f08f (diff) | |
| download | linux-943e1583bf8a5cbcedfc4a00d92d8aac9e7e436d.tar.xz | |
net: check all name nodes in __dev_alloc_name
[ Upstream commit 6c015a2256801597fadcbc11d287774c9c512fa5 ]
__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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to '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 75ca6c6d01d6..dbc286fd2047 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1195,6 +1195,18 @@ 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) |