[RFC PATCH bpf-next v1 02/14] MIPS: eBPF: mask 32-bit index for tail calls
From: Tony Ambardar <hidden>
Date: 2021-07-12 00:35:43
Also in:
bpf, linux-mips
Subsystem:
bpf jit for mips (32-bit and 64-bit), bpf [general] (safe dynamic programs and tools), mips, the rest · Maintainers:
Johan Almbladh, Paul Burton, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Thomas Bogendoerfer, Linus Torvalds
The program array index for tail-calls should be 32-bit, so zero-extend to
sanitize the value. This fixes failures seen for test_verifier test:
852/p runtime/jit: pass > 32bit index to tail_call FAIL retval 2 != 42
Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Signed-off-by: Tony Ambardar <redacted>
---
arch/mips/net/ebpf_jit.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c
index ed47a10d533f..64f76c7191b1 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c@@ -611,6 +611,8 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) * if (index >= array->map.max_entries) * goto out; */ + /* Mask index as 32-bit */ + emit_instr(ctx, dinsu, MIPS_R_A2, MIPS_R_ZERO, 32, 32); off = offsetof(struct bpf_array, map.max_entries); emit_instr(ctx, lwu, MIPS_R_T5, off, MIPS_R_A1); emit_instr(ctx, sltu, MIPS_R_AT, MIPS_R_T5, MIPS_R_A2);
--
2.25.1