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bpf: move {prev_,}insn_idx into verifier env

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commit c08435ec7f upstream.

Move prev_insn_idx and insn_idx from the do_check() function into
the verifier environment, so they can be read inside the various
helper functions for handling the instructions. It's easier to put
this into the environment rather than changing all call-sites only
to pass it along. insn_idx is useful in particular since this later
on allows to hold state in env->insn_aux_data[env->insn_idx].

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Vallish Vaidyeshwara <vallish@amazon.com>
[Backported to 4.14 by sblbir]
Signed-off-by: Balbir Singh <sblbir@amzn.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Daniel Borkmann
2019-04-03 18:39:05 +00:00
committed by Greg Kroah-Hartman
parent 8561489481
commit 6a42c49482
2 changed files with 33 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/bpf_verifier.h
View File

@@ -134,6 +134,8 @@ struct bpf_ext_analyzer_ops {
* one verifier_env per bpf_check() call
*/
struct bpf_verifier_env {
u32 insn_idx;
u32 prev_insn_idx;
struct bpf_prog *prog; /* eBPF program being verified */
struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
int stack_size; /* number of states to be processed */

64
kernel/bpf/verifier.c
View File

@@ -3892,7 +3892,6 @@ static int do_check(struct bpf_verifier_env *env)
struct bpf_insn *insns = env->prog->insnsi;
struct bpf_reg_state *regs;
int insn_cnt = env->prog->len;
int insn_idx, prev_insn_idx = 0;
int insn_processed = 0;
bool do_print_state = false;
@@ -3902,19 +3901,18 @@ static int do_check(struct bpf_verifier_env *env)
env->cur_state = state;
init_reg_state(state->regs);
state->parent = NULL;
insn_idx = 0;
for (;;) {
struct bpf_insn *insn;
u8 class;
int err;
if (insn_idx >= insn_cnt) {
if (env->insn_idx >= insn_cnt) {
verbose("invalid insn idx %d insn_cnt %d\n",
insn_idx, insn_cnt);
env->insn_idx, insn_cnt);
return -EFAULT;
}
insn = &insns[insn_idx];
insn = &insns[env->insn_idx];
class = BPF_CLASS(insn->code);
if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
@@ -3923,7 +3921,7 @@ static int do_check(struct bpf_verifier_env *env)
return -E2BIG;
}
err = is_state_visited(env, insn_idx);
err = is_state_visited(env, env->insn_idx);
if (err < 0)
return err;
if (err == 1) {
@@ -3931,9 +3929,9 @@ static int do_check(struct bpf_verifier_env *env)
if (log_level) {
if (do_print_state)
verbose("\nfrom %d to %d: safe\n",
prev_insn_idx, insn_idx);
env->prev_insn_idx, env->insn_idx);
else
verbose("%d: safe\n", insn_idx);
verbose("%d: safe\n", env->insn_idx);
}
goto process_bpf_exit;
}
@@ -3943,25 +3941,25 @@ static int do_check(struct bpf_verifier_env *env)
if (log_level > 1 || (log_level && do_print_state)) {
if (log_level > 1)
verbose("%d:", insn_idx);
verbose("%d:", env->insn_idx);
else
verbose("\nfrom %d to %d:",
prev_insn_idx, insn_idx);
env->prev_insn_idx, env->insn_idx);
print_verifier_state(env->cur_state);
do_print_state = false;
}
if (log_level) {
verbose("%d: ", insn_idx);
verbose("%d: ", env->insn_idx);
print_bpf_insn(env, insn);
}
err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx);
err = ext_analyzer_insn_hook(env, env->insn_idx, env->prev_insn_idx);
if (err)
return err;
regs = cur_regs(env);
env->insn_aux_data[insn_idx].seen = true;
env->insn_aux_data[env->insn_idx].seen = true;
if (class == BPF_ALU || class == BPF_ALU64) {
err = check_alu_op(env, insn);
if (err)
@@ -3986,13 +3984,13 @@ static int do_check(struct bpf_verifier_env *env)
/* check that memory (src_reg + off) is readable,
* the state of dst_reg will be updated by this func
*/
err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ,
insn->dst_reg, false);
err = check_mem_access(env, env->insn_idx, insn->src_reg,
insn->off, BPF_SIZE(insn->code),
BPF_READ, insn->dst_reg, false);
if (err)
return err;
prev_src_type = &env->insn_aux_data[insn_idx].ptr_type;
prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type;
if (*prev_src_type == NOT_INIT) {
/* saw a valid insn
@@ -4019,10 +4017,10 @@ static int do_check(struct bpf_verifier_env *env)
enum bpf_reg_type *prev_dst_type, dst_reg_type;
if (BPF_MODE(insn->code) == BPF_XADD) {
err = check_xadd(env, insn_idx, insn);
err = check_xadd(env, env->insn_idx, insn);
if (err)
return err;
insn_idx++;
env->insn_idx++;
continue;
}
@@ -4038,13 +4036,13 @@ static int do_check(struct bpf_verifier_env *env)
dst_reg_type = regs[insn->dst_reg].type;
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
insn->src_reg, false);
err = check_mem_access(env, env->insn_idx, insn->dst_reg,
insn->off, BPF_SIZE(insn->code),
BPF_WRITE, insn->src_reg, false);
if (err)
return err;
prev_dst_type = &env->insn_aux_data[insn_idx].ptr_type;
prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type;
if (*prev_dst_type == NOT_INIT) {
*prev_dst_type = dst_reg_type;
@@ -4073,9 +4071,9 @@ static int do_check(struct bpf_verifier_env *env)
}
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
-1, false);
err = check_mem_access(env, env->insn_idx, insn->dst_reg,
insn->off, BPF_SIZE(insn->code),
BPF_WRITE, -1, false);
if (err)
return err;
@@ -4091,7 +4089,7 @@ static int do_check(struct bpf_verifier_env *env)
return -EINVAL;
}
err = check_call(env, insn->imm, insn_idx);
err = check_call(env, insn->imm, env->insn_idx);
if (err)
return err;
@@ -4104,7 +4102,7 @@ static int do_check(struct bpf_verifier_env *env)
return -EINVAL;
}
insn_idx += insn->off + 1;
env->insn_idx += insn->off + 1;
continue;
} else if (opcode == BPF_EXIT) {
@@ -4132,7 +4130,7 @@ static int do_check(struct bpf_verifier_env *env)
}
process_bpf_exit:
err = pop_stack(env, &prev_insn_idx, &insn_idx);
err = pop_stack(env, &env->prev_insn_idx, &env->insn_idx);
if (err < 0) {
if (err != -ENOENT)
return err;
@@ -4142,7 +4140,7 @@ process_bpf_exit:
continue;
}
} else {
err = check_cond_jmp_op(env, insn, &insn_idx);
err = check_cond_jmp_op(env, insn, &env->insn_idx);
if (err)
return err;
}
@@ -4159,8 +4157,8 @@ process_bpf_exit:
if (err)
return err;
insn_idx++;
env->insn_aux_data[insn_idx].seen = true;
env->insn_idx++;
env->insn_aux_data[env->insn_idx].seen = true;
} else {
verbose("invalid BPF_LD mode\n");
return -EINVAL;
@@ -4170,7 +4168,7 @@ process_bpf_exit:
return -EINVAL;
}
insn_idx++;
env->insn_idx++;
}
verbose("processed %d insns, stack depth %d\n",