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Commit 719c44d3 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

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 19575988 ("soreuseport: add compat
case for setsockopt SO_ATTACH_REUSEPORT_CBPF").

Reported-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ca8bdaf1

include/net/compat.h

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ int compat_sock_get_timestampns(struct sock *, struct timespec __user *); 


int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,

		      struct sockaddr __user **, struct iovec **);

struct sock_fprog __user *get_compat_bpf_fprog(char __user *optval);

asmlinkage long compat_sys_sendmsg(int, struct compat_msghdr __user *,

				   unsigned int);

asmlinkage long compat_sys_sendmmsg(int, struct compat_mmsghdr __user *,

net/compat.c

+15 −2
Original line number Diff line number Diff line
@@ -309,8 +309,8 @@ void scm_detach_fds_compat(struct msghdr *kmsg, struct scm_cookie *scm) 
	__scm_destroy(scm);

}



static int do_set_attach_filter(struct socket *sock, int level, int optname,

				char __user *optval, unsigned int optlen)

/* allocate a 64-bit sock_fprog on the user stack for duration of syscall. */

struct sock_fprog __user *get_compat_bpf_fprog(char __user *optval)

{

	struct compat_sock_fprog __user *fprog32 = (struct compat_sock_fprog __user *)optval;

	struct sock_fprog __user *kfprog = compat_alloc_user_space(sizeof(struct sock_fprog));
@@ -323,6 +323,19 @@ static int do_set_attach_filter(struct socket *sock, int level, int optname, 
	    __get_user(ptr, &fprog32->filter) ||

	    __put_user(len, &kfprog->len) ||

	    __put_user(compat_ptr(ptr), &kfprog->filter))

		return NULL;



	return kfprog;

}

EXPORT_SYMBOL_GPL(get_compat_bpf_fprog);



static int do_set_attach_filter(struct socket *sock, int level, int optname,

				char __user *optval, unsigned int optlen)

{

	struct sock_fprog __user *kfprog;



	kfprog = get_compat_bpf_fprog(optval);

	if (!kfprog)

		return -EFAULT;



	return sock_setsockopt(sock, level, optname, (char __user *)kfprog,

net/packet/af_packet.c

+25 −0
Original line number Diff line number Diff line
@@ -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 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, 
}





#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 @@ static const struct proto_ops packet_ops = { 
	.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,