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authorNicolas Dichtel <nicolas.dichtel@6wind.com>2017-10-11 16:24:48 +0200
committerDavid S. Miller <davem@davemloft.net>2017-10-16 20:52:43 +0100
commit2459b4c635858094df78abb9ca87d99f89fe8ca5 (patch)
tree8255b0b57d3acb2d5fe6099702dbfd9d87b09a82
parent2fd7c5abb8f35d6b701617f49aea9f0873284aee (diff)
downloadlinux-2459b4c635858094df78abb9ca87d99f89fe8ca5.tar.bz2
net: enable interface alias removal via rtnl
IFLA_IFALIAS is defined as NLA_STRING. It means that the minimal length of the attribute is 1 ("\0"). However, to remove an alias, the attribute length must be 0 (see dev_set_alias()). Let's define the type to NLA_BINARY to allow 0-length string, so that the alias can be removed. Example: $ ip l s dummy0 alias foo $ ip l l dev dummy0 5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff alias foo Before the patch: $ ip l s dummy0 alias "" RTNETLINK answers: Numerical result out of range After the patch: $ ip l s dummy0 alias "" $ ip l l dev dummy0 5: dummy0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether ae:20:30:4f:a7:f3 brd ff:ff:ff:ff:ff:ff CC: Oliver Hartkopp <oliver@hartkopp.net> CC: Stephen Hemminger <stephen@networkplumber.org> Fixes: 96ca4a2cc145 ("net: remove ifalias on empty given alias") Reported-by: Julien FLoret <julien.floret@6wind.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/rtnetlink.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a6bcf86ce471..5ace48926b19 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1483,7 +1483,10 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
[IFLA_LINKINFO] = { .type = NLA_NESTED },
[IFLA_NET_NS_PID] = { .type = NLA_U32 },
[IFLA_NET_NS_FD] = { .type = NLA_U32 },
- [IFLA_IFALIAS] = { .type = NLA_STRING, .len = IFALIASZ-1 },
+ /* IFLA_IFALIAS is a string, but policy is set to NLA_BINARY to
+ * allow 0-length string (needed to remove an alias).
+ */
+ [IFLA_IFALIAS] = { .type = NLA_BINARY, .len = IFALIASZ - 1 },
[IFLA_VFINFO_LIST] = {. type = NLA_NESTED },
[IFLA_VF_PORTS] = { .type = NLA_NESTED },
[IFLA_PORT_SELF] = { .type = NLA_NESTED },