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| author | Willem de Bruijn <willemb@google.com> | 2016-06-07 12:06:34 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-09 23:41:03 -0700 |
| commit | 719c44d340beeecd22cbda91b00ef55585b3c1a0 (patch) | |
| tree | 5e53d5a92c7548ee9464b2133ad4651c23871297 /net/compat.c | |
| parent | ca8bdaf13abbdcbb12ff12164aa2d5b522ec524d (diff) | |
| download | lwn-719c44d340beeecd22cbda91b00ef55585b3c1a0.tar.gz lwn-719c44d340beeecd22cbda91b00ef55585b3c1a0.zip | |
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')
| -rw-r--r-- | net/compat.c | 17 |
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) __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, |