summaryrefslogtreecommitdiffstats
path: root/kernel/bpf/verifier.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r--kernel/bpf/verifier.c38
1 files changed, 28 insertions, 10 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 38cfcf701eeb..fa1d8245b925 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2118,6 +2118,15 @@ static bool register_is_const(struct bpf_reg_state *reg)
return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
}
+static bool __is_pointer_value(bool allow_ptr_leaks,
+ const struct bpf_reg_state *reg)
+{
+ if (allow_ptr_leaks)
+ return false;
+
+ return reg->type != SCALAR_VALUE;
+}
+
static void save_register_state(struct bpf_func_state *state,
int spi, struct bpf_reg_state *reg)
{
@@ -2308,6 +2317,16 @@ static int check_stack_read(struct bpf_verifier_env *env,
* which resets stack/reg liveness for state transitions
*/
state->regs[value_regno].live |= REG_LIVE_WRITTEN;
+ } else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
+ /* If value_regno==-1, the caller is asking us whether
+ * it is acceptable to use this value as a SCALAR_VALUE
+ * (e.g. for XADD).
+ * We must not allow unprivileged callers to do that
+ * with spilled pointers.
+ */
+ verbose(env, "leaking pointer from stack off %d\n",
+ off);
+ return -EACCES;
}
mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
} else {
@@ -2673,15 +2692,6 @@ static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
return -EACCES;
}
-static bool __is_pointer_value(bool allow_ptr_leaks,
- const struct bpf_reg_state *reg)
-{
- if (allow_ptr_leaks)
- return false;
-
- return reg->type != SCALAR_VALUE;
-}
-
static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
{
return cur_regs(env) + regno;
@@ -3089,7 +3099,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
if (ret < 0)
return ret;
- if (atype == BPF_READ) {
+ if (atype == BPF_READ && value_regno >= 0) {
if (ret == SCALAR_VALUE) {
mark_reg_unknown(env, regs, value_regno);
return 0;
@@ -10487,6 +10497,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return -EINVAL;
}
env->ops = bpf_verifier_ops[tgt_prog->type];
+ prog->expected_attach_type = tgt_prog->expected_attach_type;
}
if (!tgt_prog->jited) {
verbose(env, "Can attach to only JITed progs\n");
@@ -10831,6 +10842,13 @@ err_release_maps:
* them now. Otherwise free_used_maps() will release them.
*/
release_maps(env);
+
+ /* extension progs temporarily inherit the attach_type of their targets
+ for verification purposes, so set it back to zero before returning
+ */
+ if (env->prog->type == BPF_PROG_TYPE_EXT)
+ env->prog->expected_attach_type = 0;
+
*prog = env->prog;
err_unlock:
if (!is_priv)