seccomp selects BPF only instead of whole NET
Other BPF users (like tracing filters) will select BPF only too
Signed-off-by: Alexei Starovoitov <a...@plumgrid.com>
---
arch/Kconfig | 3 ++-
net/Kconfig | 4 ++++
net/Makefile | 2 +-
net/bpf/core.c | 21 +++++++++++++++++++++
4 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 97ff872c7acc..92f43a16eccc 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -324,7 +324,8 @@ config HAVE_ARCH_SECCOMP_FILTER
config SECCOMP_FILTER
def_bool y
- depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
+ depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP
+ select BPF
help
Enable tasks to build secure computing environments defined
in terms of Berkeley Packet Filter programs which implement
diff --git a/net/Kconfig b/net/Kconfig
index d92afe4204d9..e8dca9f836d9 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -6,6 +6,7 @@ menuconfig NET
bool "Networking support"
select NLATTR
select GENERIC_NET_UTILS
+ select BPF
---help---
Unless you really know what you are doing, you should say Y here.
The reason is that some programs need kernel networking support even
@@ -370,6 +371,9 @@ source "net/nfc/Kconfig"
endif # if NET
+config BPF
+ boolean
+
# Used by archs to tell that they support BPF_JIT
config HAVE_BPF_JIT
bool
diff --git a/net/Makefile b/net/Makefile
index d0e89323aee3..d56447bca1aa 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -8,7 +8,7 @@
obj-y := nonet.o
obj-$(CONFIG_NET) := socket.o core/
-obj-$(CONFIG_NET) += bpf/
+obj-$(CONFIG_BPF) += bpf/
tmp-$(CONFIG_COMPAT) := compat.o
obj-$(CONFIG_NET) += $(tmp-y)
diff --git a/net/bpf/core.c b/net/bpf/core.c
index 22c2d99414c0..8ca1b37ddc28 100644
--- a/net/bpf/core.c
+++ b/net/bpf/core.c
@@ -1040,3 +1040,24 @@ void sk_filter_free(struct sk_filter *fp)
bpf_jit_free(fp);
}
EXPORT_SYMBOL_GPL(sk_filter_free);
+
+/* kernel configuration that do not enable NET are not using
+ * classic BPF extensions
+ */
+bool __weak sk_convert_bpf_extensions(struct sock_filter *fp,
+ struct sock_filter_int **insnp)
+{
+ return false;
+}
+
+/* To emulate LD_ABS/LD_IND instructions __sk_run_filter() may call
+ * skb_copy_bits(), so provide a weak definition for it in NET-less config.
+ * seccomp_check_filter() verifies that seccomp filters are not using
+ * LD_ABS/LD_IND instructions. Other BPF users (like tracing filters)
+ * must not use these instructions unless ctx==skb
+ */
+int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
+ int len)
+{
+ return -EFAULT;
+}
--
1.7.9.5
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