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arp: Validate netmask earlier for SIOCDARP and SIOCSARP in arp_ioctl().

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When ioctl(SIOCDARP/SIOCSARP) is issued with ATF_PUBL, r.arp_netmask
must be 0.0.0.0 or 255.255.255.255.

Currently, the netmask is validated in arp_req_delete_public() or
arp_req_set_public() under rtnl_lock().

We have ATF_NETMASK test in arp_ioctl() before holding rtnl_lock(),
so let's move the netmask validation there.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240430015813.71143-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2024-04-29 18:58:08 -07:00 committed by Jakub Kicinski
parent 42033d0cfc
commit 0592367424
1 changed files with 15 additions and 12 deletions
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27
net/ipv4/arp.c
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@ -1023,11 +1023,8 @@ static int arp_req_set_proxy(struct net *net, struct net_device *dev, int on)
static int arp_req_set_public(struct net *net, struct arpreq *r,
struct net_device *dev)
{
__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
if (mask && mask != htonl(0xFFFFFFFF))
return -EINVAL;
if (!dev && (r->arp_flags & ATF_COM)) {
dev = dev_getbyhwaddr_rcu(net, r->arp_ha.sa_family,
r->arp_ha.sa_data);
@ -1035,6 +1032,8 @@ static int arp_req_set_public(struct net *net, struct arpreq *r,
return -ENODEV;
}
if (mask) {
__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
if (!pneigh_lookup(&arp_tbl, net, &ip, dev, 1))
return -ENOBUFS;
return 0;
@ -1171,14 +1170,13 @@ int arp_invalidate(struct net_device *dev, __be32 ip, bool force)
static int arp_req_delete_public(struct net *net, struct arpreq *r,
struct net_device *dev)
{
__be32 ip = ((struct sockaddr_in *) &r->arp_pa)->sin_addr.s_addr;
__be32 mask = ((struct sockaddr_in *)&r->arp_netmask)->sin_addr.s_addr;
if (mask == htonl(0xFFFFFFFF))
return pneigh_delete(&arp_tbl, net, &ip, dev);
if (mask) {
__be32 ip = ((struct sockaddr_in *)&r->arp_pa)->sin_addr.s_addr;
if (mask)
return -EINVAL;
return pneigh_delete(&arp_tbl, net, &ip, dev);
}
return arp_req_set_proxy(net, dev, 0);
}
@ -1211,9 +1209,10 @@ static int arp_req_delete(struct net *net, struct arpreq *r,
int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
{
int err;
struct arpreq r;
struct net_device *dev = NULL;
struct arpreq r;
__be32 *netmask;
int err;
switch (cmd) {
case SIOCDARP:
@ -1236,9 +1235,13 @@ int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg)
if (!(r.arp_flags & ATF_PUBL) &&
(r.arp_flags & (ATF_NETMASK | ATF_DONTPUB)))
return -EINVAL;
netmask = &((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr;
if (!(r.arp_flags & ATF_NETMASK))
((struct sockaddr_in *)&r.arp_netmask)->sin_addr.s_addr =
htonl(0xFFFFFFFFUL);
*netmask = htonl(0xFFFFFFFFUL);
else if (*netmask && *netmask != htonl(0xFFFFFFFFUL))
return -EINVAL;
rtnl_lock();
if (r.arp_dev[0]) {
err = -ENODEV;