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authorWillem de Bruijn <willemb@google.com>2016-06-07 12:06:34 -0400
committerDavid S. Miller <davem@davemloft.net>2016-06-09 23:41:03 -0700
commit719c44d340beeecd22cbda91b00ef55585b3c1a0 (patch)
tree5e53d5a92c7548ee9464b2133ad4651c23871297
parentca8bdaf13abbdcbb12ff12164aa2d5b522ec524d (diff)
downloadlinux-719c44d340beeecd22cbda91b00ef55585b3c1a0.tar.gz
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>
-rw-r--r--include/net/compat.h1
-rw-r--r--net/compat.c17
-rw-r--r--net/packet/af_packet.c25
3 files changed, 41 insertions, 2 deletions
diff --git a/include/net/compat.h b/include/net/compat.h
index 48103cf94e97..13de0ccaa059 100644
--- a/include/net/compat.h
+++ b/include/net/compat.h
@@ -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 *,
diff --git a/net/compat.c b/net/compat.c
index 1373947efb50..1cd2ec046164 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -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,
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4040eb92d9c9..9bff6ef16fa7 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 @@ 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,