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bpf: split explored_states

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split explored_states into prune_point boolean mark
and link list of explored states.
This removes STATE_LIST_MARK hack and allows marks to be separate from states.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov 2019-05-21 20:17:06 -07:00 committed by Daniel Borkmann
parent 5d83902167
commit a8f500af0c
2 changed files with 14 additions and 18 deletions
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1
include/linux/bpf_verifier.h
View File

@ -233,6 +233,7 @@ struct bpf_insn_aux_data {
int sanitize_stack_off; /* stack slot to be cleared */
bool seen; /* this insn was processed by the verifier */
u8 alu_state; /* used in combination with alu_limit */
bool prune_point;
unsigned int orig_idx; /* original instruction index */
};

31
kernel/bpf/verifier.c
View File

@ -5436,7 +5436,6 @@ enum {
BRANCH = 2,
};
#define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
static struct bpf_verifier_state_list **explored_state(
struct bpf_verifier_env *env,
int idx)
@ -5446,7 +5445,7 @@ static struct bpf_verifier_state_list **explored_state(
static void init_explored_state(struct bpf_verifier_env *env, int idx)
{
env->explored_states[idx] = STATE_LIST_MARK;
env->insn_aux_data[idx].prune_point = true;
}
/* t, w, e - match pseudo-code above:
@ -6018,10 +6017,7 @@ static void clean_live_states(struct bpf_verifier_env *env, int insn,
int i;
sl = *explored_state(env, insn);
if (!sl)
return;
while (sl != STATE_LIST_MARK) {
while (sl) {
if (sl->state.curframe != cur->curframe)
goto next;
for (i = 0; i <= cur->curframe; i++)
@ -6376,18 +6372,18 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
struct bpf_verifier_state *cur = env->cur_state, *new;
int i, j, err, states_cnt = 0;
pprev = explored_state(env, insn_idx);
sl = *pprev;
if (!sl)
if (!env->insn_aux_data[insn_idx].prune_point)
/* this 'insn_idx' instruction wasn't marked, so we will not
* be doing state search here
*/
return 0;
pprev = explored_state(env, insn_idx);
sl = *pprev;
clean_live_states(env, insn_idx, cur);
while (sl != STATE_LIST_MARK) {
while (sl) {
if (states_equal(env, &sl->state, cur)) {
sl->hit_cnt++;
/* reached equivalent register/stack state,
@ -8145,13 +8141,12 @@ static void free_states(struct bpf_verifier_env *env)
for (i = 0; i < env->prog->len; i++) {
sl = env->explored_states[i];
if (sl)
while (sl != STATE_LIST_MARK) {
sln = sl->next;
free_verifier_state(&sl->state, false);
kfree(sl);
sl = sln;
}
while (sl) {
sln = sl->next;
free_verifier_state(&sl->state, false);
kfree(sl);
sl = sln;
}
}
kvfree(env->explored_states);