path: root/net/compat.c
diff options
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 /net/compat.c
parentca8bdaf13abbdcbb12ff12164aa2d5b522ec524d (diff)
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>
Diffstat (limited to 'net/compat.c')
1 files changed, 15 insertions, 2 deletions
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)
-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;
+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,