sock_diag: fix filter code sent to userspace

Filters need to be translated to real BPF code for userland, like SO_GETFILTER. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
mariux64 · Jun 11, 2013 · ed13998 · ed13998
1 parent 92bb73e
commit ed13998
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Showing 3 changed files with 9 additions and 3 deletions.
diff --git a/include/linux/filter.h b/include/linux/filter.h
@@ -46,6 +46,7 @@ extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 extern int sk_detach_filter(struct sock *sk);
 extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
 extern int sk_get_filter(struct sock *sk, struct sock_filter __user *filter, unsigned len);
+extern void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to);
 
 #ifdef CONFIG_BPF_JIT
 #include <stdarg.h>

diff --git a/net/core/filter.c b/net/core/filter.c
@@ -778,7 +778,7 @@ int sk_detach_filter(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(sk_detach_filter);
 
-static void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
+void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
 {
 	static const u16 decodes[] = {
 		[BPF_S_ALU_ADD_K]	= BPF_ALU|BPF_ADD|BPF_K,

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
@@ -73,8 +73,13 @@ int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
 		goto out;
 	}
 
-	if (filter)
-		memcpy(nla_data(attr), filter->insns, len);
+	if (filter) {
+		struct sock_filter *fb = (struct sock_filter *)nla_data(attr);
+		int i;
+
+		for (i = 0; i < filter->len; i++, fb++)
+			sk_decode_filter(&filter->insns[i], fb);
+	}
 
 out:
 	rcu_read_unlock();