| Message ID | 20250212113218.9859-1-oscmaes92@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: 802: enforce underlying device type for GARP and MRP | expand |
On Wed, Feb 12, 2025 at 12:32:18PM +0100, Oscar Maes wrote: > When creating a VLAN device, we initialize GARP (garp_init_applicant) > and MRP (mrp_init_applicant) for the underlying device. > > As part of the initialization process, we add the multicast address of > each applicant to the underlying device, by calling dev_mc_add. > > __dev_mc_add uses dev->addr_len to determine the length of the new > multicast address. > > This causes an out-of-bounds read if dev->addr_len is greater than 6, > since the multicast addresses provided by GARP and MRP are only 6 bytes > long. > > This behaviour can be reproduced using the following commands: > > ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo > ip l set up dev gretest > ip link add link gretest name vlantest type vlan id 100 > > Then, the following command will display the address of garp_pdu_rcv: > > ip maddr show | grep 01:80:c2:00:00:21 > > Fix this by enforcing the type and address length of > the underlying device during GARP and MRP initialization. > > Fixes: 22bedad3ce11 ("net: convert multicast list to list_head") > Reported-by: syzbot <syzbot+91161fe81857b396c8a0@syzkaller.appspotmail.com> > Closes: https://lore.kernel.org/netdev/000000000000ca9a81061a01ec20@google.com/ > Signed-off-by: Oscar Maes <oscmaes92@gmail.com> > --- > net/802/garp.c | 5 +++++ > net/802/mrp.c | 5 +++++ > 2 files changed, 10 insertions(+) > Hi, This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him a patch that has triggered this response. He used to manually respond to these common problems, but in order to save his sanity (he kept writing the same thing over and over, yet to different people), I was created. Hopefully you will not take offence and will fix the problem in your patch and resubmit it so that it can be accepted into the Linux kernel tree. You are receiving this message because of the following common error(s) as indicated below: - You have marked a patch with a "Fixes:" tag for a commit that is in an older released kernel, yet you do not have a cc: stable line in the signed-off-by area at all, which means that the patch will not be applied to any older kernel releases. To properly fix this, please follow the documented rules in the Documentation/process/stable-kernel-rules.rst file for how to resolve this. If you wish to discuss this problem further, or you have questions about how to resolve this issue, please feel free to respond to this email and Greg will reply once he has dug out from the pending patches received from other developers. thanks, greg k-h's patch email bot
On Wed, Feb 12, 2025 at 12:32:18PM +0100, Oscar Maes wrote: > When creating a VLAN device, we initialize GARP (garp_init_applicant) > and MRP (mrp_init_applicant) for the underlying device. > > As part of the initialization process, we add the multicast address of > each applicant to the underlying device, by calling dev_mc_add. > > __dev_mc_add uses dev->addr_len to determine the length of the new > multicast address. > > This causes an out-of-bounds read if dev->addr_len is greater than 6, > since the multicast addresses provided by GARP and MRP are only 6 bytes > long. > > This behaviour can be reproduced using the following commands: > > ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo > ip l set up dev gretest > ip link add link gretest name vlantest type vlan id 100 > > Then, the following command will display the address of garp_pdu_rcv: > > ip maddr show | grep 01:80:c2:00:00:21 > > Fix this by enforcing the type and address length of > the underlying device during GARP and MRP initialization. > > Fixes: 22bedad3ce11 ("net: convert multicast list to list_head") > Reported-by: syzbot <syzbot+91161fe81857b396c8a0@syzkaller.appspotmail.com> > Closes: https://lore.kernel.org/netdev/000000000000ca9a81061a01ec20@google.com/ > Signed-off-by: Oscar Maes <oscmaes92@gmail.com> > --- > net/802/garp.c | 5 +++++ > net/802/mrp.c | 5 +++++ > 2 files changed, 10 insertions(+) > > diff --git a/net/802/garp.c b/net/802/garp.c > index 27f0ab146..2f383ee73 100644 > --- a/net/802/garp.c > +++ b/net/802/garp.c > @@ -9,6 +9,7 @@ > #include <linux/skbuff.h> > #include <linux/netdevice.h> > #include <linux/etherdevice.h> > +#include <linux/if_arp.h> > #include <linux/rtnetlink.h> > #include <linux/llc.h> > #include <linux/slab.h> > @@ -574,6 +575,10 @@ int garp_init_applicant(struct net_device *dev, struct garp_application *appl) > > ASSERT_RTNL(); > > + err = -EINVAL; > + if (dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN) Checking for 'ARPHRD_ETHER' is not enough? Other virtual devices such as macsec, macvlan and ipvlan only look at 'dev->type' AFAICT. Also, how about moving this to vlan_check_real_dev()? It's common to both the IOCTL and netlink paths. > + goto err1; > + > if (!rtnl_dereference(dev->garp_port)) { > err = garp_init_port(dev); > if (err < 0) > diff --git a/net/802/mrp.c b/net/802/mrp.c > index e0c96d0da..1efee0b39 100644 > --- a/net/802/mrp.c > +++ b/net/802/mrp.c > @@ -12,6 +12,7 @@ > #include <linux/skbuff.h> > #include <linux/netdevice.h> > #include <linux/etherdevice.h> > +#include <linux/if_arp.h> > #include <linux/rtnetlink.h> > #include <linux/slab.h> > #include <linux/module.h> > @@ -859,6 +860,10 @@ int mrp_init_applicant(struct net_device *dev, struct mrp_application *appl) > > ASSERT_RTNL(); > > + err = -EINVAL; > + if (dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN) > + goto err1; > + > if (!rtnl_dereference(dev->mrp_port)) { > err = mrp_init_port(dev); > if (err < 0) > -- > 2.39.5 > >
diff --git a/net/802/garp.c b/net/802/garp.c index 27f0ab146..2f383ee73 100644 --- a/net/802/garp.c +++ b/net/802/garp.c @@ -9,6 +9,7 @@ #include <linux/skbuff.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> +#include <linux/if_arp.h> #include <linux/rtnetlink.h> #include <linux/llc.h> #include <linux/slab.h> @@ -574,6 +575,10 @@ int garp_init_applicant(struct net_device *dev, struct garp_application *appl) ASSERT_RTNL(); + err = -EINVAL; + if (dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN) + goto err1; + if (!rtnl_dereference(dev->garp_port)) { err = garp_init_port(dev); if (err < 0) diff --git a/net/802/mrp.c b/net/802/mrp.c index e0c96d0da..1efee0b39 100644 --- a/net/802/mrp.c +++ b/net/802/mrp.c @@ -12,6 +12,7 @@ #include <linux/skbuff.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> +#include <linux/if_arp.h> #include <linux/rtnetlink.h> #include <linux/slab.h> #include <linux/module.h> @@ -859,6 +860,10 @@ int mrp_init_applicant(struct net_device *dev, struct mrp_application *appl) ASSERT_RTNL(); + err = -EINVAL; + if (dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN) + goto err1; + if (!rtnl_dereference(dev->mrp_port)) { err = mrp_init_port(dev); if (err < 0)
When creating a VLAN device, we initialize GARP (garp_init_applicant) and MRP (mrp_init_applicant) for the underlying device. As part of the initialization process, we add the multicast address of each applicant to the underlying device, by calling dev_mc_add. __dev_mc_add uses dev->addr_len to determine the length of the new multicast address. This causes an out-of-bounds read if dev->addr_len is greater than 6, since the multicast addresses provided by GARP and MRP are only 6 bytes long. This behaviour can be reproduced using the following commands: ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo ip l set up dev gretest ip link add link gretest name vlantest type vlan id 100 Then, the following command will display the address of garp_pdu_rcv: ip maddr show | grep 01:80:c2:00:00:21 Fix this by enforcing the type and address length of the underlying device during GARP and MRP initialization. Fixes: 22bedad3ce11 ("net: convert multicast list to list_head") Reported-by: syzbot <syzbot+91161fe81857b396c8a0@syzkaller.appspotmail.com> Closes: https://lore.kernel.org/netdev/000000000000ca9a81061a01ec20@google.com/ Signed-off-by: Oscar Maes <oscmaes92@gmail.com> --- net/802/garp.c | 5 +++++ net/802/mrp.c | 5 +++++ 2 files changed, 10 insertions(+)