From: Or Cohen orcohen@paloaltonetworks.com
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to 4.9, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org --- net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index fb643945e424..b5b79f501541 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2161,7 +2161,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, int skb_len = skb->len; unsigned int snaplen, res; unsigned long status = TP_STATUS_USER; - unsigned short macoff, netoff, hdrlen; + unsigned short macoff, hdrlen; + unsigned int netoff; struct sk_buff *copy_skb = NULL; struct timespec ts; __u32 ts_status; @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, } macoff = netoff - maclen; } + if (netoff > USHRT_MAX) { + spin_lock(&sk->sk_receive_queue.lock); + po->stats.stats1.tp_drops++; + spin_unlock(&sk->sk_receive_queue.lock); + goto drop_n_restore; + } if (po->tp_version <= TPACKET_V2) { if (macoff + snaplen > po->rx_ring.frame_size) { if (po->copy_thresh &&
On Fri, Sep 04, 2020 at 03:30:52PM +0200, Stefan Nuernberger wrote:
From: Or Cohen orcohen@paloaltonetworks.com
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to 4.9, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org
net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
What is the git commit id of this patch in Linus's tree?
thanks,
greg k-h
On Fri, 2020-09-04 at 16:16 +0200, Greg Kroah-Hartman wrote:
On Fri, Sep 04, 2020 at 03:30:52PM +0200, Stefan Nuernberger wrote:
From: Or Cohen orcohen@paloaltonetworks.com
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to 4.9, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org
net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
What is the git commit id of this patch in Linus's tree?
Sorry, this isn't merged on Linus' tree yet. It's a heads up that the backport isn't straightforward.
Best, Stefan
thanks,
greg k-h
Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879
On Fri, Sep 04, 2020 at 02:22:46PM +0000, Nuernberger, Stefan wrote:
On Fri, 2020-09-04 at 16:16 +0200, Greg Kroah-Hartman wrote:
On Fri, Sep 04, 2020 at 03:30:52PM +0200, Stefan Nuernberger wrote:
From: Or Cohen orcohen@paloaltonetworks.com
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to 4.9, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org
net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
What is the git commit id of this patch in Linus's tree?
Sorry, this isn't merged on Linus' tree yet. It's a heads up that the backport isn't straightforward.
Ok, please be more specific about this when sending patches out...
greg k-h
Hi,
On Fri, Sep 04, 2020 at 04:36:48PM +0200, gregkh@linuxfoundation.org wrote:
On Fri, Sep 04, 2020 at 02:22:46PM +0000, Nuernberger, Stefan wrote:
On Fri, 2020-09-04 at 16:16 +0200, Greg Kroah-Hartman wrote:
On Fri, Sep 04, 2020 at 03:30:52PM +0200, Stefan Nuernberger wrote:
From: Or Cohen orcohen@paloaltonetworks.com
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to 4.9, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org
net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
What is the git commit id of this patch in Linus's tree?
Sorry, this isn't merged on Linus' tree yet. It's a heads up that the backport isn't straightforward.
Ok, please be more specific about this when sending patches out...
The commit is in Linux' tree now as acf69c946233259ab4d64f8869d4037a198c7f06 .
Older stable series, which do not have 8e8e2951e309 ("net/packet: make tp_drops atomic") will though need a backport as per above AFICS.
Regards, Salvatore
From: Or Cohen orcohen@paloaltonetworks.com
commit acf69c946233259ab4d64f8869d4037a198c7f06 upstream.
Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short.
This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb.
The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX.
This addresses CVE-2020-14386
Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen orcohen@paloaltonetworks.com Signed-off-by: Eric Dumazet edumazet@google.com
[ snu: backported to pre-5.3, changed tp_drops counting/locking ]
Signed-off-by: Stefan Nuernberger snu@amazon.com CC: David Woodhouse dwmw@amazon.co.uk CC: Amit Shah aams@amazon.com CC: stable@vger.kernel.org --- net/packet/af_packet.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index fb643945e424..b5b79f501541 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2161,7 +2161,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, int skb_len = skb->len; unsigned int snaplen, res; unsigned long status = TP_STATUS_USER; - unsigned short macoff, netoff, hdrlen; + unsigned short macoff, hdrlen; + unsigned int netoff; struct sk_buff *copy_skb = NULL; struct timespec ts; __u32 ts_status; @@ -2223,6 +2224,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, } macoff = netoff - maclen; } + if (netoff > USHRT_MAX) { + spin_lock(&sk->sk_receive_queue.lock); + po->stats.stats1.tp_drops++; + spin_unlock(&sk->sk_receive_queue.lock); + goto drop_n_restore; + } if (po->tp_version <= TPACKET_V2) { if (macoff + snaplen > po->rx_ring.frame_size) { if (po->copy_thresh &&
linux-stable-mirror@lists.linaro.org
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