From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
kernel-team@fb.com, yonghong.song@linux.dev, memxor@gmail.com,
awerner32@gmail.com, Eduard Zingerman <eddyz87@gmail.com>
Subject: [PATCH bpf v3 05/11] bpf: extract setup_func_entry() utility function
Date: Tue, 21 Nov 2023 00:59:39 +0200 [thread overview]
Message-ID: <20231120225945.11741-6-eddyz87@gmail.com> (raw)
In-Reply-To: <20231120225945.11741-1-eddyz87@gmail.com>
Move code for simulated stack frame creation to a separate utility
function. This function would be used in the follow-up change for
callbacks handling.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
kernel/bpf/verifier.c | 84 ++++++++++++++++++++++++-------------------
1 file changed, 48 insertions(+), 36 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e6e1bcfe00f5..68ee4803d3a2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9370,11 +9370,10 @@ static int set_callee_state(struct bpf_verifier_env *env,
struct bpf_func_state *caller,
struct bpf_func_state *callee, int insn_idx);
-static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
- int *insn_idx, int subprog,
- set_callee_state_fn set_callee_state_cb)
+static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int callsite,
+ set_callee_state_fn set_callee_state_cb,
+ struct bpf_verifier_state *state)
{
- struct bpf_verifier_state *state = env->cur_state;
struct bpf_func_state *caller, *callee;
int err;
@@ -9384,13 +9383,53 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -E2BIG;
}
- caller = state->frame[state->curframe];
if (state->frame[state->curframe + 1]) {
verbose(env, "verifier bug. Frame %d already allocated\n",
state->curframe + 1);
return -EFAULT;
}
+ caller = state->frame[state->curframe];
+ callee = kzalloc(sizeof(*callee), GFP_KERNEL);
+ if (!callee)
+ return -ENOMEM;
+ state->frame[state->curframe + 1] = callee;
+
+ /* callee cannot access r0, r6 - r9 for reading and has to write
+ * into its own stack before reading from it.
+ * callee can read/write into caller's stack
+ */
+ init_func_state(env, callee,
+ /* remember the callsite, it will be used by bpf_exit */
+ callsite,
+ state->curframe + 1 /* frameno within this callchain */,
+ subprog /* subprog number within this prog */);
+ /* Transfer references to the callee */
+ err = copy_reference_state(callee, caller);
+ err = err ?: set_callee_state_cb(env, caller, callee, callsite);
+ if (err)
+ goto err_out;
+
+ /* only increment it after check_reg_arg() finished */
+ state->curframe++;
+
+ return 0;
+
+err_out:
+ free_func_state(callee);
+ state->frame[state->curframe + 1] = NULL;
+ return err;
+}
+
+static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ int *insn_idx, int subprog,
+ set_callee_state_fn set_callee_state_cb)
+{
+ struct bpf_verifier_state *state = env->cur_state;
+ struct bpf_func_state *caller, *callee;
+ int err;
+
+ caller = state->frame[state->curframe];
err = btf_check_subprog_call(env, subprog, caller->regs);
if (err == -EFAULT)
return err;
@@ -9460,35 +9499,12 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return 0;
}
- callee = kzalloc(sizeof(*callee), GFP_KERNEL);
- if (!callee)
- return -ENOMEM;
- state->frame[state->curframe + 1] = callee;
-
- /* callee cannot access r0, r6 - r9 for reading and has to write
- * into its own stack before reading from it.
- * callee can read/write into caller's stack
- */
- init_func_state(env, callee,
- /* remember the callsite, it will be used by bpf_exit */
- *insn_idx /* callsite */,
- state->curframe + 1 /* frameno within this callchain */,
- subprog /* subprog number within this prog */);
-
- /* Transfer references to the callee */
- err = copy_reference_state(callee, caller);
+ err = setup_func_entry(env, subprog, *insn_idx, set_callee_state_cb, state);
if (err)
- goto err_out;
-
- err = set_callee_state_cb(env, caller, callee, *insn_idx);
- if (err)
- goto err_out;
+ return err;
clear_caller_saved_regs(env, caller->regs);
- /* only increment it after check_reg_arg() finished */
- state->curframe++;
-
/* and go analyze first insn of the callee */
*insn_idx = env->subprog_info[subprog].start - 1;
@@ -9496,14 +9512,10 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
verbose(env, "caller:\n");
print_verifier_state(env, caller, true);
verbose(env, "callee:\n");
- print_verifier_state(env, callee, true);
+ print_verifier_state(env, state->frame[state->curframe], true);
}
- return 0;
-err_out:
- free_func_state(callee);
- state->frame[state->curframe + 1] = NULL;
- return err;
+ return 0;
}
int map_set_for_each_callback_args(struct bpf_verifier_env *env,
--
2.42.1
next prev parent reply other threads:[~2023-11-20 23:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-20 22:59 [PATCH bpf v3 00/11] verify callbacks as if they are called unknown number of times Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 01/11] selftests/bpf: track tcp payload offset as scalar in xdp_synproxy Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 02/11] selftests/bpf: track string payload offset as scalar in strobemeta Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 03/11] selftests/bpf: fix bpf_loop_bench for new callback verification scheme Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 04/11] bpf: extract __check_reg_arg() utility function Eduard Zingerman
2023-11-20 22:59 ` Eduard Zingerman [this message]
2023-11-20 22:59 ` [PATCH bpf v3 06/11] bpf: verify callbacks as if they are called unknown number of times Eduard Zingerman
2023-11-21 1:00 ` Andrii Nakryiko
2023-11-21 1:06 ` Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 07/11] selftests/bpf: tests for iterating callbacks Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 08/11] bpf: widening for callback iterators Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 09/11] selftests/bpf: test widening for iterating callbacks Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 10/11] bpf: keep track of max number of bpf_loop callback iterations Eduard Zingerman
2023-11-21 1:04 ` Andrii Nakryiko
2023-11-21 1:09 ` Eduard Zingerman
2023-11-21 1:14 ` Andrii Nakryiko
2023-11-21 1:26 ` Alexei Starovoitov
2023-11-21 1:35 ` Eduard Zingerman
2023-11-20 22:59 ` [PATCH bpf v3 11/11] selftests/bpf: check if max number of bpf_loop iterations is tracked Eduard Zingerman
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