s390/bpf,jit: initialize A register if 1st insn is BPF_S_LDX_B_MSH

commit 6e0de817594c61f3b392a9245deeb09609ec707d upstream.

The A register needs to be initialized to zero in the prolog if the
first instruction of the BPF program is BPF_S_LDX_B_MSH to prevent
leaking the content of %r5 to user space.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 1919db6c06077d887fae4a74f119cb220c7bc6b3..3bc6b7e43b2494ff54ee2725ea06020c1b58d01c 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -243,7 +243,6 @@ static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
        case BPF_S_LD_W_IND:
        case BPF_S_LD_H_IND:
        case BPF_S_LD_B_IND:
-       case BPF_S_LDX_B_MSH:
        case BPF_S_LD_IMM:
        case BPF_S_LD_MEM:
        case BPF_S_MISC_TXA: