From 719c44d340beeecd22cbda91b00ef55585b3c1a0 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 7 Jun 2016 12:06:34 -0400 Subject: 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 Signed-off-by: Willem de Bruijn Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/compat.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'net/compat.c') 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, -- cgit v1.2.3-59-g8ed1b