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

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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 9c36dc398f9070afb4d6151d214623d1cbcf9f4a..452d3ebd9d0fba3b513a6978b096bd22b27c1b46 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -276,7 +276,6 @@ 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: