packet: compat support for sock_fprog
Socket option PACKET_FANOUT_DATA takes a struct sock_fprog as argument
if PACKET_FANOUT has mode PACKET_FANOUT_CBPF. This structure contains
a pointer into user memory. If userland is 32-bit and kernel is 64-bit
the two disagree about the layout of struct sock_fprog.
Add compat setsockopt support to convert a 32-bit compat_sock_fprog to
a 64-bit sock_fprog. This is analogous to compat_sock_fprog support for
SO_REUSEPORT added in commit 1957598840f4 ("soreuseport: add compat
case for setsockopt SO_ATTACH_REUSEPORT_CBPF").
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4040eb9..9bff6ef 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -93,6 +93,7 @@
#include <net/inet_common.h>
#endif
#include <linux/bpf.h>
+#include <net/compat.h>
#include "internal.h"
@@ -3940,6 +3941,27 @@
}
+#ifdef CONFIG_COMPAT
+static int compat_packet_setsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, unsigned int optlen)
+{
+ struct packet_sock *po = pkt_sk(sock->sk);
+
+ if (level != SOL_PACKET)
+ return -ENOPROTOOPT;
+
+ if (optname == PACKET_FANOUT_DATA &&
+ po->fanout && po->fanout->type == PACKET_FANOUT_CBPF) {
+ optval = (char __user *)get_compat_bpf_fprog(optval);
+ if (!optval)
+ return -EFAULT;
+ optlen = sizeof(struct sock_fprog);
+ }
+
+ return packet_setsockopt(sock, level, optname, optval, optlen);
+}
+#endif
+
static int packet_notifier(struct notifier_block *this,
unsigned long msg, void *ptr)
{
@@ -4416,6 +4438,9 @@
.shutdown = sock_no_shutdown,
.setsockopt = packet_setsockopt,
.getsockopt = packet_getsockopt,
+#ifdef CONFIG_COMPAT
+ .compat_setsockopt = compat_packet_setsockopt,
+#endif
.sendmsg = packet_sendmsg,
.recvmsg = packet_recvmsg,
.mmap = packet_mmap,