This is a note to let you know that I've just added the patch titled
bpf: refactor fixup_bpf_calls()
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: bpf-refactor-fixup_bpf_calls.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 79741b3bdec01a8628368fbcfccc7d189ed606cb Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov ast@fb.com Date: Wed, 15 Mar 2017 18:26:40 -0700 Subject: bpf: refactor fixup_bpf_calls()
From: Alexei Starovoitov ast@fb.com
commit 79741b3bdec01a8628368fbcfccc7d189ed606cb upstream.
reduce indent and make it iterate over instructions similar to convert_ctx_accesses(). Also convert hard BUG_ON into soft verifier error.
Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: David S. Miller davem@davemloft.net Cc: Jiri Slaby jslaby@suse.cz [Backported to 4.9.y - gregkh] Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/bpf/verifier.c | 75 +++++++++++++++++++++++--------------------------- 1 file changed, 35 insertions(+), 40 deletions(-)
--- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3362,55 +3362,50 @@ static int convert_ctx_accesses(struct b return 0; }
-/* fixup insn->imm field of bpf_call instructions: - * if (insn->imm == BPF_FUNC_map_lookup_elem) - * insn->imm = bpf_map_lookup_elem - __bpf_call_base; - * else if (insn->imm == BPF_FUNC_map_update_elem) - * insn->imm = bpf_map_update_elem - __bpf_call_base; - * else ... +/* fixup insn->imm field of bpf_call instructions * * this function is called after eBPF program passed verification */ -static void fixup_bpf_calls(struct bpf_prog *prog) +static int fixup_bpf_calls(struct bpf_verifier_env *env) { + struct bpf_prog *prog = env->prog; + struct bpf_insn *insn = prog->insnsi; const struct bpf_func_proto *fn; + const int insn_cnt = prog->len; int i;
- for (i = 0; i < prog->len; i++) { - struct bpf_insn *insn = &prog->insnsi[i]; - - if (insn->code == (BPF_JMP | BPF_CALL)) { - /* we reach here when program has bpf_call instructions - * and it passed bpf_check(), means that - * ops->get_func_proto must have been supplied, check it - */ - BUG_ON(!prog->aux->ops->get_func_proto); - - if (insn->imm == BPF_FUNC_get_route_realm) - prog->dst_needed = 1; - if (insn->imm == BPF_FUNC_get_prandom_u32) - bpf_user_rnd_init_once(); - if (insn->imm == BPF_FUNC_tail_call) { - /* mark bpf_tail_call as different opcode - * to avoid conditional branch in - * interpeter for every normal call - * and to prevent accidental JITing by - * JIT compiler that doesn't support - * bpf_tail_call yet - */ - insn->imm = 0; - insn->code |= BPF_X; - continue; - } + for (i = 0; i < insn_cnt; i++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL)) + continue; + + if (insn->imm == BPF_FUNC_get_route_realm) + prog->dst_needed = 1; + if (insn->imm == BPF_FUNC_get_prandom_u32) + bpf_user_rnd_init_once(); + if (insn->imm == BPF_FUNC_tail_call) { + /* mark bpf_tail_call as different opcode to avoid + * conditional branch in the interpeter for every normal + * call and to prevent accidental JITing by JIT compiler + * that doesn't support bpf_tail_call yet + */ + insn->imm = 0; + insn->code |= BPF_X; + continue; + }
- fn = prog->aux->ops->get_func_proto(insn->imm); - /* all functions that have prototype and verifier allowed - * programs to call them, must be real in-kernel functions - */ - BUG_ON(!fn->func); - insn->imm = fn->func - __bpf_call_base; + fn = prog->aux->ops->get_func_proto(insn->imm); + /* all functions that have prototype and verifier allowed + * programs to call them, must be real in-kernel functions + */ + if (!fn->func) { + verbose("kernel subsystem misconfigured func %d\n", + insn->imm); + return -EFAULT; } + insn->imm = fn->func - __bpf_call_base; } + + return 0; }
static void free_states(struct bpf_verifier_env *env) @@ -3515,7 +3510,7 @@ skip_full_check: ret = convert_ctx_accesses(env);
if (ret == 0) - fixup_bpf_calls(env->prog); + ret = fixup_bpf_calls(env);
if (log_level && log_len >= log_size - 1) { BUG_ON(log_len >= log_size);
Patches currently in stable-queue which might be from ast@fb.com are
queue-4.9/bpf-refactor-fixup_bpf_calls.patch queue-4.9/bpf-move-fixup_bpf_calls-function.patch