From 904e6ddf4133c52fdb9654c2cd2ad90f320d48b9 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Tue, 13 Jun 2023 18:38:21 +0300 Subject: bpf: Use scalar ids in mark_chain_precision() Change mark_chain_precision() to track precision in situations like below: r2 = unknown value ... --- state #0 --- ... r1 = r2 // r1 and r2 now share the same ID ... --- state #1 {r1.id = A, r2.id = A} --- ... if (r2 > 10) goto exit; // find_equal_scalars() assigns range to r1 ... --- state #2 {r1.id = A, r2.id = A} --- r3 = r10 r3 += r1 // need to mark both r1 and r2 At the beginning of the processing of each state, ensure that if a register with a scalar ID is marked as precise, all registers sharing this ID are also marked as precise. This property would be used by a follow-up change in regsafe(). Signed-off-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20230613153824.3324830-2-eddyz87@gmail.com --- include/linux/bpf_verifier.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'include/linux/bpf_verifier.h') diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 5b11a3b0fec0..22fb13c738a9 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -557,6 +557,11 @@ struct backtrack_state { u64 stack_masks[MAX_CALL_FRAMES]; }; +struct bpf_idset { + u32 count; + u32 ids[BPF_ID_MAP_SIZE]; +}; + /* single container for all structs * one verifier_env per bpf_check() call */ @@ -588,7 +593,10 @@ struct bpf_verifier_env { const struct bpf_line_info *prev_linfo; struct bpf_verifier_log log; struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 1]; - struct bpf_id_pair idmap_scratch[BPF_ID_MAP_SIZE]; + union { + struct bpf_id_pair idmap_scratch[BPF_ID_MAP_SIZE]; + struct bpf_idset idset_scratch; + }; struct { int *insn_state; int *insn_stack; -- cgit v1.2.3