1 files changed, 50 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0099-bpf-arsh-is-not-supported-in-32-bit-alu-thus-reject-.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0099-bpf-arsh-is-not-supported-in-32-bit-alu-thus-reject-.patch
new file mode 100644
index 00000000..acbc5668
--- /dev/null
+++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0099-bpf-arsh-is-not-supported-in-32-bit-alu-thus-reject-.patch
@@ -0,0 +1,50 @@
+From d4d31ba0cca574288cdaef8002d11cf27b300d0f Mon Sep 17 00:00:00 2001
+From: Daniel Borkmann <daniel@iogearbox.net>
+Date: Mon, 29 Jan 2018 02:48:57 +0100
+Subject: [PATCH 099/103] bpf: arsh is not supported in 32 bit alu thus reject
+ it
+
+[ upstream commit 7891a87efc7116590eaba57acc3c422487802c6f ]
+
+The following snippet was throwing an 'unknown opcode cc' warning
+in BPF interpreter:
+
+  0: (18) r0 = 0x0
+  2: (7b) *(u64 *)(r10 -16) = r0
+  3: (cc) (u32) r0 s>>= (u32) r0
+  4: (95) exit
+
+Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
+generation, not all of them do and interpreter does neither. We can
+leave existing ones and implement it later in bpf-next for the
+remaining ones, but reject this properly in verifier for the time
+being.
+
+Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
+Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
+Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
+Signed-off-by: Alexei Starovoitov <ast@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/bpf/verifier.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
+index 6767670..6caf0ff1 100644
+--- a/kernel/bpf/verifier.c
++++ b/kernel/bpf/verifier.c
+@@ -1753,6 +1753,11 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
+ 			return -EINVAL;
+ 		}
+ 
++		if (opcode == BPF_ARSH && BPF_CLASS(insn->code) != BPF_ALU64) {
++			verbose("BPF_ARSH not supported for 32 bit ALU\n");
++			return -EINVAL;
++		}
++
+ 		if ((opcode == BPF_LSH || opcode == BPF_RSH ||
+ 		     opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
+ 			int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
+-- 
+2.7.4
+