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-rw-r--r--kernel/bpf/core.c8
-rw-r--r--kernel/bpf/verifier.c87
2 files changed, 66 insertions, 29 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 08626b519ce2..cd3afe57ece3 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -64,8 +64,8 @@
#define OFF insn->off
#define IMM insn->imm
-struct bpf_mem_alloc bpf_global_ma, bpf_global_percpu_ma;
-bool bpf_global_ma_set, bpf_global_percpu_ma_set;
+struct bpf_mem_alloc bpf_global_ma;
+bool bpf_global_ma_set;
/* No hurry in this branch
*
@@ -2934,9 +2934,7 @@ static int __init bpf_global_ma_init(void)
ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
bpf_global_ma_set = !ret;
- ret = bpf_mem_alloc_init(&bpf_global_percpu_ma, 0, true);
- bpf_global_percpu_ma_set = !ret;
- return !bpf_global_ma_set || !bpf_global_percpu_ma_set;
+ return ret;
}
late_initcall(bpf_global_ma_init);
#endif
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bd1c42eb540f..6da370a047fe 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -26,6 +26,7 @@
#include <linux/poison.h>
#include <linux/module.h>
#include <linux/cpumask.h>
+#include <linux/bpf_mem_alloc.h>
#include <net/xdp.h>
#include "disasm.h"
@@ -41,6 +42,9 @@ static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
#undef BPF_LINK_TYPE
};
+struct bpf_mem_alloc bpf_global_percpu_ma;
+static bool bpf_global_percpu_ma_set;
+
/* bpf_check() is a static code analyzer that walks eBPF program
* instruction by instruction and updates register/stack state.
* All paths of conditional branches are analyzed until 'bpf_exit' insn.
@@ -336,6 +340,7 @@ struct bpf_kfunc_call_arg_meta {
struct btf *btf_vmlinux;
static DEFINE_MUTEX(bpf_verifier_lock);
+static DEFINE_MUTEX(bpf_percpu_ma_lock);
static const struct bpf_line_info *
find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
@@ -3516,12 +3521,29 @@ static int push_jmp_history(struct bpf_verifier_env *env,
/* Backtrack one insn at a time. If idx is not at the top of recorded
* history then previous instruction came from straight line execution.
+ * Return -ENOENT if we exhausted all instructions within given state.
+ *
+ * It's legal to have a bit of a looping with the same starting and ending
+ * insn index within the same state, e.g.: 3->4->5->3, so just because current
+ * instruction index is the same as state's first_idx doesn't mean we are
+ * done. If there is still some jump history left, we should keep going. We
+ * need to take into account that we might have a jump history between given
+ * state's parent and itself, due to checkpointing. In this case, we'll have
+ * history entry recording a jump from last instruction of parent state and
+ * first instruction of given state.
*/
static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
u32 *history)
{
u32 cnt = *history;
+ if (i == st->first_insn_idx) {
+ if (cnt == 0)
+ return -ENOENT;
+ if (cnt == 1 && st->jmp_history[0].idx == i)
+ return -ENOENT;
+ }
+
if (cnt && st->jmp_history[cnt - 1].idx == i) {
i = st->jmp_history[cnt - 1].prev_idx;
(*history)--;
@@ -4401,10 +4423,10 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno)
* Nothing to be tracked further in the parent state.
*/
return 0;
- if (i == first_idx)
- break;
subseq_idx = i;
i = get_prev_insn_idx(st, i, &history);
+ if (i == -ENOENT)
+ break;
if (i >= env->prog->len) {
/* This can happen if backtracking reached insn 0
* and there are still reg_mask or stack_mask
@@ -12074,8 +12096,19 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set)
return -ENOMEM;
- if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl] && !bpf_global_percpu_ma_set)
- return -ENOMEM;
+ if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
+ if (!bpf_global_percpu_ma_set) {
+ mutex_lock(&bpf_percpu_ma_lock);
+ if (!bpf_global_percpu_ma_set) {
+ err = bpf_mem_alloc_init(&bpf_global_percpu_ma, 0, true);
+ if (!err)
+ bpf_global_percpu_ma_set = true;
+ }
+ mutex_unlock(&bpf_percpu_ma_lock);
+ if (err)
+ return err;
+ }
+ }
if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
@@ -15386,8 +15419,7 @@ enum {
* w - next instruction
* e - edge
*/
-static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
- bool loop_ok)
+static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
{
int *insn_stack = env->cfg.insn_stack;
int *insn_state = env->cfg.insn_state;
@@ -15419,7 +15451,7 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
insn_stack[env->cfg.cur_stack++] = w;
return KEEP_EXPLORING;
} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
- if (loop_ok && env->bpf_capable)
+ if (env->bpf_capable)
return DONE_EXPLORING;
verbose_linfo(env, t, "%d: ", t);
verbose_linfo(env, w, "%d: ", w);
@@ -15439,24 +15471,20 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns,
struct bpf_verifier_env *env,
bool visit_callee)
{
- int ret;
+ int ret, insn_sz;
- ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
+ insn_sz = bpf_is_ldimm64(&insns[t]) ? 2 : 1;
+ ret = push_insn(t, t + insn_sz, FALLTHROUGH, env);
if (ret)
return ret;
- mark_prune_point(env, t + 1);
+ mark_prune_point(env, t + insn_sz);
/* when we exit from subprog, we need to record non-linear history */
- mark_jmp_point(env, t + 1);
+ mark_jmp_point(env, t + insn_sz);
if (visit_callee) {
mark_prune_point(env, t);
- ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env,
- /* It's ok to allow recursion from CFG point of
- * view. __check_func_call() will do the actual
- * check.
- */
- bpf_pseudo_func(insns + t));
+ ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
}
return ret;
}
@@ -15469,15 +15497,17 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns,
static int visit_insn(int t, struct bpf_verifier_env *env)
{
struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
- int ret, off;
+ int ret, off, insn_sz;
if (bpf_pseudo_func(insn))
return visit_func_call_insn(t, insns, env, true);
/* All non-branch instructions have a single fall-through edge. */
if (BPF_CLASS(insn->code) != BPF_JMP &&
- BPF_CLASS(insn->code) != BPF_JMP32)
- return push_insn(t, t + 1, FALLTHROUGH, env, false);
+ BPF_CLASS(insn->code) != BPF_JMP32) {
+ insn_sz = bpf_is_ldimm64(insn) ? 2 : 1;
+ return push_insn(t, t + insn_sz, FALLTHROUGH, env);
+ }
switch (BPF_OP(insn->code)) {
case BPF_EXIT:
@@ -15523,8 +15553,7 @@ static int visit_insn(int t, struct bpf_verifier_env *env)
off = insn->imm;
/* unconditional jump with single edge */
- ret = push_insn(t, t + off + 1, FALLTHROUGH, env,
- true);
+ ret = push_insn(t, t + off + 1, FALLTHROUGH, env);
if (ret)
return ret;
@@ -15537,11 +15566,11 @@ static int visit_insn(int t, struct bpf_verifier_env *env)
/* conditional jump with two edges */
mark_prune_point(env, t);
- ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
+ ret = push_insn(t, t + 1, FALLTHROUGH, env);
if (ret)
return ret;
- return push_insn(t, t + insn->off + 1, BRANCH, env, true);
+ return push_insn(t, t + insn->off + 1, BRANCH, env);
}
}
@@ -15607,11 +15636,21 @@ walk_cfg:
}
for (i = 0; i < insn_cnt; i++) {
+ struct bpf_insn *insn = &env->prog->insnsi[i];
+
if (insn_state[i] != EXPLORED) {
verbose(env, "unreachable insn %d\n", i);
ret = -EINVAL;
goto err_free;
}
+ if (bpf_is_ldimm64(insn)) {
+ if (insn_state[i + 1] != 0) {
+ verbose(env, "jump into the middle of ldimm64 insn %d\n", i);
+ ret = -EINVAL;
+ goto err_free;
+ }
+ i++; /* skip second half of ldimm64 */
+ }
}
ret = 0; /* cfg looks good */
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-09 22:14:46 +0100