bpf: Add missed newline in verifier verbose log
[linux-2.6-microblaze.git] / kernel / bpf / verifier.c
index ce166a0..48718e1 100644 (file)
@@ -176,7 +176,6 @@ struct bpf_verifier_stack_elem {
        struct bpf_verifier_stack_elem *next;
 };
 
-#define BPF_COMPLEXITY_LIMIT_INSNS     131072
 #define BPF_COMPLEXITY_LIMIT_STACK     1024
 #define BPF_COMPLEXITY_LIMIT_STATES    64
 
@@ -212,7 +211,7 @@ struct bpf_call_arg_meta {
        int access_size;
        s64 msize_smax_value;
        u64 msize_umax_value;
-       int ptr_id;
+       int ref_obj_id;
        int func_id;
 };
 
@@ -346,35 +345,23 @@ static bool reg_type_may_be_null(enum bpf_reg_type type)
               type == PTR_TO_TCP_SOCK_OR_NULL;
 }
 
-static bool type_is_refcounted(enum bpf_reg_type type)
-{
-       return type == PTR_TO_SOCKET;
-}
-
-static bool type_is_refcounted_or_null(enum bpf_reg_type type)
-{
-       return type == PTR_TO_SOCKET || type == PTR_TO_SOCKET_OR_NULL;
-}
-
-static bool reg_is_refcounted(const struct bpf_reg_state *reg)
-{
-       return type_is_refcounted(reg->type);
-}
-
 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
 {
        return reg->type == PTR_TO_MAP_VALUE &&
                map_value_has_spin_lock(reg->map_ptr);
 }
 
-static bool reg_is_refcounted_or_null(const struct bpf_reg_state *reg)
+static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
 {
-       return type_is_refcounted_or_null(reg->type);
+       return type == PTR_TO_SOCKET ||
+               type == PTR_TO_SOCKET_OR_NULL ||
+               type == PTR_TO_TCP_SOCK ||
+               type == PTR_TO_TCP_SOCK_OR_NULL;
 }
 
-static bool arg_type_is_refcounted(enum bpf_arg_type type)
+static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
 {
-       return type == ARG_PTR_TO_SOCKET;
+       return type == ARG_PTR_TO_SOCK_COMMON;
 }
 
 /* Determine whether the function releases some resources allocated by another
@@ -389,7 +376,14 @@ static bool is_release_function(enum bpf_func_id func_id)
 static bool is_acquire_function(enum bpf_func_id func_id)
 {
        return func_id == BPF_FUNC_sk_lookup_tcp ||
-               func_id == BPF_FUNC_sk_lookup_udp;
+               func_id == BPF_FUNC_sk_lookup_udp ||
+               func_id == BPF_FUNC_skc_lookup_tcp;
+}
+
+static bool is_ptr_cast_function(enum bpf_func_id func_id)
+{
+       return func_id == BPF_FUNC_tcp_sock ||
+               func_id == BPF_FUNC_sk_fullsock;
 }
 
 /* string representation of 'enum bpf_reg_type' */
@@ -466,6 +460,8 @@ static void print_verifier_state(struct bpf_verifier_env *env,
                                verbose(env, ",call_%d", func(env, reg)->callsite);
                } else {
                        verbose(env, "(id=%d", reg->id);
+                       if (reg_type_may_be_refcounted_or_null(t))
+                               verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
                        if (t != SCALAR_VALUE)
                                verbose(env, ",off=%d", reg->off);
                        if (type_is_pkt_pointer(t))
@@ -1095,7 +1091,7 @@ static int check_subprogs(struct bpf_verifier_env *env)
         */
        subprog[env->subprog_cnt].start = insn_cnt;
 
-       if (env->log.level > 1)
+       if (env->log.level & BPF_LOG_LEVEL2)
                for (i = 0; i < env->subprog_cnt; i++)
                        verbose(env, "func#%d @%d\n", i, subprog[i].start);
 
@@ -1142,6 +1138,7 @@ static int mark_reg_read(struct bpf_verifier_env *env,
                         struct bpf_reg_state *parent)
 {
        bool writes = parent == state->parent; /* Observe write marks */
+       int cnt = 0;
 
        while (parent) {
                /* if read wasn't screened by an earlier write ... */
@@ -1153,12 +1150,25 @@ static int mark_reg_read(struct bpf_verifier_env *env,
                                parent->var_off.value, parent->off);
                        return -EFAULT;
                }
+               if (parent->live & REG_LIVE_READ)
+                       /* The parentage chain never changes and
+                        * this parent was already marked as LIVE_READ.
+                        * There is no need to keep walking the chain again and
+                        * keep re-marking all parents as LIVE_READ.
+                        * This case happens when the same register is read
+                        * multiple times without writes into it in-between.
+                        */
+                       break;
                /* ... then we depend on parent's value */
                parent->live |= REG_LIVE_READ;
                state = parent;
                parent = state->parent;
                writes = true;
+               cnt++;
        }
+
+       if (env->longest_mark_read_walk < cnt)
+               env->longest_mark_read_walk = cnt;
        return 0;
 }
 
@@ -1416,7 +1426,7 @@ static int check_stack_access(struct bpf_verifier_env *env,
                char tn_buf[48];
 
                tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
-               verbose(env, "variable stack access var_off=%s off=%d size=%d",
+               verbose(env, "variable stack access var_off=%s off=%d size=%d\n",
                        tn_buf, off, size);
                return -EACCES;
        }
@@ -1458,7 +1468,7 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno,
         * need to try adding each of min_value and max_value to off
         * to make sure our theoretical access will be safe.
         */
-       if (env->log.level)
+       if (env->log.level & BPF_LOG_LEVEL)
                print_verifier_state(env, state);
 
        /* The minimum value is only important with signed
@@ -2160,6 +2170,29 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
                                BPF_SIZE(insn->code), BPF_WRITE, -1, true);
 }
 
+static int __check_stack_boundary(struct bpf_verifier_env *env, u32 regno,
+                                 int off, int access_size,
+                                 bool zero_size_allowed)
+{
+       struct bpf_reg_state *reg = reg_state(env, regno);
+
+       if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
+           access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
+               if (tnum_is_const(reg->var_off)) {
+                       verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
+                               regno, off, access_size);
+               } else {
+                       char tn_buf[48];
+
+                       tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+                       verbose(env, "invalid stack type R%d var_off=%s access_size=%d\n",
+                               regno, tn_buf, access_size);
+               }
+               return -EACCES;
+       }
+       return 0;
+}
+
 /* when register 'regno' is passed into function that will read 'access_size'
  * bytes from that pointer, make sure that it's within stack boundary
  * and all elements of stack are initialized.
@@ -2172,7 +2205,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
 {
        struct bpf_reg_state *reg = reg_state(env, regno);
        struct bpf_func_state *state = func(env, reg);
-       int off, i, slot, spi;
+       int err, min_off, max_off, i, slot, spi;
 
        if (reg->type != PTR_TO_STACK) {
                /* Allow zero-byte read from NULL, regardless of pointer type */
@@ -2186,21 +2219,57 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
                return -EACCES;
        }
 
-       /* Only allow fixed-offset stack reads */
-       if (!tnum_is_const(reg->var_off)) {
-               char tn_buf[48];
+       if (tnum_is_const(reg->var_off)) {
+               min_off = max_off = reg->var_off.value + reg->off;
+               err = __check_stack_boundary(env, regno, min_off, access_size,
+                                            zero_size_allowed);
+               if (err)
+                       return err;
+       } else {
+               /* Variable offset is prohibited for unprivileged mode for
+                * simplicity since it requires corresponding support in
+                * Spectre masking for stack ALU.
+                * See also retrieve_ptr_limit().
+                */
+               if (!env->allow_ptr_leaks) {
+                       char tn_buf[48];
 
-               tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
-               verbose(env, "invalid variable stack read R%d var_off=%s\n",
-                       regno, tn_buf);
-               return -EACCES;
-       }
-       off = reg->off + reg->var_off.value;
-       if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
-           access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
-               verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
-                       regno, off, access_size);
-               return -EACCES;
+                       tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+                       verbose(env, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n",
+                               regno, tn_buf);
+                       return -EACCES;
+               }
+               /* Only initialized buffer on stack is allowed to be accessed
+                * with variable offset. With uninitialized buffer it's hard to
+                * guarantee that whole memory is marked as initialized on
+                * helper return since specific bounds are unknown what may
+                * cause uninitialized stack leaking.
+                */
+               if (meta && meta->raw_mode)
+                       meta = NULL;
+
+               if (reg->smax_value >= BPF_MAX_VAR_OFF ||
+                   reg->smax_value <= -BPF_MAX_VAR_OFF) {
+                       verbose(env, "R%d unbounded indirect variable offset stack access\n",
+                               regno);
+                       return -EACCES;
+               }
+               min_off = reg->smin_value + reg->off;
+               max_off = reg->smax_value + reg->off;
+               err = __check_stack_boundary(env, regno, min_off, access_size,
+                                            zero_size_allowed);
+               if (err) {
+                       verbose(env, "R%d min value is outside of stack bound\n",
+                               regno);
+                       return err;
+               }
+               err = __check_stack_boundary(env, regno, max_off, access_size,
+                                            zero_size_allowed);
+               if (err) {
+                       verbose(env, "R%d max value is outside of stack bound\n",
+                               regno);
+                       return err;
+               }
        }
 
        if (meta && meta->raw_mode) {
@@ -2209,10 +2278,10 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
                return 0;
        }
 
-       for (i = 0; i < access_size; i++) {
+       for (i = min_off; i < max_off + access_size; i++) {
                u8 *stype;
 
-               slot = -(off + i) - 1;
+               slot = -i - 1;
                spi = slot / BPF_REG_SIZE;
                if (state->allocated_stack <= slot)
                        goto err;
@@ -2225,8 +2294,16 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
                        goto mark;
                }
 err:
-               verbose(env, "invalid indirect read from stack off %d+%d size %d\n",
-                       off, i, access_size);
+               if (tnum_is_const(reg->var_off)) {
+                       verbose(env, "invalid indirect read from stack off %d+%d size %d\n",
+                               min_off, i - min_off, access_size);
+               } else {
+                       char tn_buf[48];
+
+                       tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+                       verbose(env, "invalid indirect read from stack var_off %s+%d size %d\n",
+                               tn_buf, i - min_off, access_size);
+               }
                return -EACCES;
 mark:
                /* reading any byte out of 8-byte 'spill_slot' will cause
@@ -2235,7 +2312,7 @@ mark:
                mark_reg_read(env, &state->stack[spi].spilled_ptr,
                              state->stack[spi].spilled_ptr.parent);
        }
-       return update_stack_depth(env, state, off);
+       return update_stack_depth(env, state, min_off);
 }
 
 static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
@@ -2414,16 +2491,15 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
                /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
                if (!type_is_sk_pointer(type))
                        goto err_type;
-       } else if (arg_type == ARG_PTR_TO_SOCKET) {
-               expected_type = PTR_TO_SOCKET;
-               if (type != expected_type)
-                       goto err_type;
-               if (meta->ptr_id || !reg->id) {
-                       verbose(env, "verifier internal error: mismatched references meta=%d, reg=%d\n",
-                               meta->ptr_id, reg->id);
-                       return -EFAULT;
+               if (reg->ref_obj_id) {
+                       if (meta->ref_obj_id) {
+                               verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+                                       regno, reg->ref_obj_id,
+                                       meta->ref_obj_id);
+                               return -EFAULT;
+                       }
+                       meta->ref_obj_id = reg->ref_obj_id;
                }
-               meta->ptr_id = reg->id;
        } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
                if (meta->func_id == BPF_FUNC_spin_lock) {
                        if (process_spin_lock(env, regno, true))
@@ -2740,32 +2816,38 @@ static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
        return true;
 }
 
-static bool check_refcount_ok(const struct bpf_func_proto *fn)
+static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id)
 {
        int count = 0;
 
-       if (arg_type_is_refcounted(fn->arg1_type))
+       if (arg_type_may_be_refcounted(fn->arg1_type))
                count++;
-       if (arg_type_is_refcounted(fn->arg2_type))
+       if (arg_type_may_be_refcounted(fn->arg2_type))
                count++;
-       if (arg_type_is_refcounted(fn->arg3_type))
+       if (arg_type_may_be_refcounted(fn->arg3_type))
                count++;
-       if (arg_type_is_refcounted(fn->arg4_type))
+       if (arg_type_may_be_refcounted(fn->arg4_type))
                count++;
-       if (arg_type_is_refcounted(fn->arg5_type))
+       if (arg_type_may_be_refcounted(fn->arg5_type))
                count++;
 
+       /* A reference acquiring function cannot acquire
+        * another refcounted ptr.
+        */
+       if (is_acquire_function(func_id) && count)
+               return false;
+
        /* We only support one arg being unreferenced at the moment,
         * which is sufficient for the helper functions we have right now.
         */
        return count <= 1;
 }
 
-static int check_func_proto(const struct bpf_func_proto *fn)
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
 {
        return check_raw_mode_ok(fn) &&
               check_arg_pair_ok(fn) &&
-              check_refcount_ok(fn) ? 0 : -EINVAL;
+              check_refcount_ok(fn, func_id) ? 0 : -EINVAL;
 }
 
 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
@@ -2799,19 +2881,20 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
 }
 
 static void release_reg_references(struct bpf_verifier_env *env,
-                                  struct bpf_func_state *state, int id)
+                                  struct bpf_func_state *state,
+                                  int ref_obj_id)
 {
        struct bpf_reg_state *regs = state->regs, *reg;
        int i;
 
        for (i = 0; i < MAX_BPF_REG; i++)
-               if (regs[i].id == id)
+               if (regs[i].ref_obj_id == ref_obj_id)
                        mark_reg_unknown(env, regs, i);
 
        bpf_for_each_spilled_reg(i, state, reg) {
                if (!reg)
                        continue;
-               if (reg_is_refcounted(reg) && reg->id == id)
+               if (reg->ref_obj_id == ref_obj_id)
                        __mark_reg_unknown(reg);
        }
 }
@@ -2820,15 +2903,20 @@ static void release_reg_references(struct bpf_verifier_env *env,
  * resources. Identify all copies of the same pointer and clear the reference.
  */
 static int release_reference(struct bpf_verifier_env *env,
-                            struct bpf_call_arg_meta *meta)
+                            int ref_obj_id)
 {
        struct bpf_verifier_state *vstate = env->cur_state;
+       int err;
        int i;
 
+       err = release_reference_state(cur_func(env), ref_obj_id);
+       if (err)
+               return err;
+
        for (i = 0; i <= vstate->curframe; i++)
-               release_reg_references(env, vstate->frame[i], meta->ptr_id);
+               release_reg_references(env, vstate->frame[i], ref_obj_id);
 
-       return release_reference_state(cur_func(env), meta->ptr_id);
+       return 0;
 }
 
 static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
@@ -2897,7 +2985,7 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
        /* and go analyze first insn of the callee */
        *insn_idx = target_insn;
 
-       if (env->log.level) {
+       if (env->log.level & BPF_LOG_LEVEL) {
                verbose(env, "caller:\n");
                print_verifier_state(env, caller);
                verbose(env, "callee:\n");
@@ -2937,7 +3025,7 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
                return err;
 
        *insn_idx = callee->callsite + 1;
-       if (env->log.level) {
+       if (env->log.level & BPF_LOG_LEVEL) {
                verbose(env, "returning from callee:\n");
                print_verifier_state(env, callee);
                verbose(env, "to caller at %d:\n", *insn_idx);
@@ -3047,7 +3135,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
        memset(&meta, 0, sizeof(meta));
        meta.pkt_access = fn->pkt_access;
 
-       err = check_func_proto(fn);
+       err = check_func_proto(fn, func_id);
        if (err) {
                verbose(env, "kernel subsystem misconfigured func %s#%d\n",
                        func_id_name(func_id), func_id);
@@ -3093,7 +3181,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
                        return err;
                }
        } else if (is_release_function(func_id)) {
-               err = release_reference(env, &meta);
+               err = release_reference(env, meta.ref_obj_id);
                if (err) {
                        verbose(env, "func %s#%d reference has not been acquired before\n",
                                func_id_name(func_id), func_id);
@@ -3149,17 +3237,11 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
        } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
                mark_reg_known_zero(env, regs, BPF_REG_0);
                regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;
-               if (is_acquire_function(func_id)) {
-                       int id = acquire_reference_state(env, insn_idx);
-
-                       if (id < 0)
-                               return id;
-                       /* For release_reference() */
-                       regs[BPF_REG_0].id = id;
-               } else {
-                       /* For mark_ptr_or_null_reg() */
-                       regs[BPF_REG_0].id = ++env->id_gen;
-               }
+               regs[BPF_REG_0].id = ++env->id_gen;
+       } else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) {
+               mark_reg_known_zero(env, regs, BPF_REG_0);
+               regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;
+               regs[BPF_REG_0].id = ++env->id_gen;
        } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {
                mark_reg_known_zero(env, regs, BPF_REG_0);
                regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
@@ -3170,6 +3252,20 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
                return -EINVAL;
        }
 
+       if (is_ptr_cast_function(func_id)) {
+               /* For release_reference() */
+               regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+       } else if (is_acquire_function(func_id)) {
+               int id = acquire_reference_state(env, insn_idx);
+
+               if (id < 0)
+                       return id;
+               /* For mark_ptr_or_null_reg() */
+               regs[BPF_REG_0].id = id;
+               /* For release_reference() */
+               regs[BPF_REG_0].ref_obj_id = id;
+       }
+
        do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
 
        err = check_map_func_compatibility(env, meta.map_ptr, func_id);
@@ -3268,6 +3364,9 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
 
        switch (ptr_reg->type) {
        case PTR_TO_STACK:
+               /* Indirect variable offset stack access is prohibited in
+                * unprivileged mode so it's not handled here.
+                */
                off = ptr_reg->off + ptr_reg->var_off.value;
                if (mask_to_left)
                        *ptr_limit = MAX_BPF_STACK + off;
@@ -3368,7 +3467,7 @@ do_sim:
                *dst_reg = *ptr_reg;
        }
        ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true);
-       if (!ptr_is_dst_reg)
+       if (!ptr_is_dst_reg && ret)
                *dst_reg = tmp;
        return !ret ? -EFAULT : 0;
 }
@@ -4665,11 +4764,19 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
                } else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
                        reg->type = PTR_TO_TCP_SOCK;
                }
-               if (is_null || !(reg_is_refcounted(reg) ||
-                                reg_may_point_to_spin_lock(reg))) {
-                       /* We don't need id from this point onwards anymore,
-                        * thus we should better reset it, so that state
-                        * pruning has chances to take effect.
+               if (is_null) {
+                       /* We don't need id and ref_obj_id from this point
+                        * onwards anymore, thus we should better reset it,
+                        * so that state pruning has chances to take effect.
+                        */
+                       reg->id = 0;
+                       reg->ref_obj_id = 0;
+               } else if (!reg_may_point_to_spin_lock(reg)) {
+                       /* For not-NULL ptr, reg->ref_obj_id will be reset
+                        * in release_reg_references().
+                        *
+                        * reg->id is still used by spin_lock ptr. Other
+                        * than spin_lock ptr type, reg->id can be reset.
                         */
                        reg->id = 0;
                }
@@ -4684,11 +4791,16 @@ static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
 {
        struct bpf_func_state *state = vstate->frame[vstate->curframe];
        struct bpf_reg_state *reg, *regs = state->regs;
+       u32 ref_obj_id = regs[regno].ref_obj_id;
        u32 id = regs[regno].id;
        int i, j;
 
-       if (reg_is_refcounted_or_null(&regs[regno]) && is_null)
-               release_reference_state(state, id);
+       if (ref_obj_id && ref_obj_id == id && is_null)
+               /* regs[regno] is in the " == NULL" branch.
+                * No one could have freed the reference state before
+                * doing the NULL check.
+                */
+               WARN_ON_ONCE(release_reference_state(state, id));
 
        for (i = 0; i < MAX_BPF_REG; i++)
                mark_ptr_or_null_reg(state, &regs[i], id, is_null);
@@ -4939,7 +5051,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
                        insn->dst_reg);
                return -EACCES;
        }
-       if (env->log.level)
+       if (env->log.level & BPF_LOG_LEVEL)
                print_verifier_state(env, this_branch->frame[this_branch->curframe]);
        return 0;
 }
@@ -5237,13 +5349,13 @@ static int check_cfg(struct bpf_verifier_env *env)
        int ret = 0;
        int i, t;
 
-       insn_state = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+       insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
        if (!insn_state)
                return -ENOMEM;
 
-       insn_stack = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+       insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
        if (!insn_stack) {
-               kfree(insn_state);
+               kvfree(insn_state);
                return -ENOMEM;
        }
 
@@ -5341,8 +5453,8 @@ check_state:
        ret = 0; /* cfg looks good */
 
 err_free:
-       kfree(insn_state);
-       kfree(insn_stack);
+       kvfree(insn_state);
+       kvfree(insn_stack);
        return ret;
 }
 
@@ -6052,15 +6164,17 @@ static int propagate_liveness(struct bpf_verifier_env *env,
        }
        /* Propagate read liveness of registers... */
        BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
-       /* We don't need to worry about FP liveness because it's read-only */
-       for (i = 0; i < BPF_REG_FP; i++) {
-               if (vparent->frame[vparent->curframe]->regs[i].live & REG_LIVE_READ)
-                       continue;
-               if (vstate->frame[vstate->curframe]->regs[i].live & REG_LIVE_READ) {
-                       err = mark_reg_read(env, &vstate->frame[vstate->curframe]->regs[i],
-                                           &vparent->frame[vstate->curframe]->regs[i]);
-                       if (err)
-                               return err;
+       for (frame = 0; frame <= vstate->curframe; frame++) {
+               /* We don't need to worry about FP liveness, it's read-only */
+               for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
+                       if (vparent->frame[frame]->regs[i].live & REG_LIVE_READ)
+                               continue;
+                       if (vstate->frame[frame]->regs[i].live & REG_LIVE_READ) {
+                               err = mark_reg_read(env, &vstate->frame[frame]->regs[i],
+                                                   &vparent->frame[frame]->regs[i]);
+                               if (err)
+                                       return err;
+                       }
                }
        }
 
@@ -6083,11 +6197,13 @@ static int propagate_liveness(struct bpf_verifier_env *env,
 static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 {
        struct bpf_verifier_state_list *new_sl;
-       struct bpf_verifier_state_list *sl;
+       struct bpf_verifier_state_list *sl, **pprev;
        struct bpf_verifier_state *cur = env->cur_state, *new;
        int i, j, err, states_cnt = 0;
 
-       sl = env->explored_states[insn_idx];
+       pprev = &env->explored_states[insn_idx];
+       sl = *pprev;
+
        if (!sl)
                /* this 'insn_idx' instruction wasn't marked, so we will not
                 * be doing state search here
@@ -6098,6 +6214,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 
        while (sl != STATE_LIST_MARK) {
                if (states_equal(env, &sl->state, cur)) {
+                       sl->hit_cnt++;
                        /* reached equivalent register/stack state,
                         * prune the search.
                         * Registers read by the continuation are read by us.
@@ -6113,10 +6230,40 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
                                return err;
                        return 1;
                }
-               sl = sl->next;
                states_cnt++;
+               sl->miss_cnt++;
+               /* heuristic to determine whether this state is beneficial
+                * to keep checking from state equivalence point of view.
+                * Higher numbers increase max_states_per_insn and verification time,
+                * but do not meaningfully decrease insn_processed.
+                */
+               if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
+                       /* the state is unlikely to be useful. Remove it to
+                        * speed up verification
+                        */
+                       *pprev = sl->next;
+                       if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
+                               free_verifier_state(&sl->state, false);
+                               kfree(sl);
+                               env->peak_states--;
+                       } else {
+                               /* cannot free this state, since parentage chain may
+                                * walk it later. Add it for free_list instead to
+                                * be freed at the end of verification
+                                */
+                               sl->next = env->free_list;
+                               env->free_list = sl;
+                       }
+                       sl = *pprev;
+                       continue;
+               }
+               pprev = &sl->next;
+               sl = *pprev;
        }
 
+       if (env->max_states_per_insn < states_cnt)
+               env->max_states_per_insn = states_cnt;
+
        if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
                return 0;
 
@@ -6130,6 +6277,8 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
        new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
        if (!new_sl)
                return -ENOMEM;
+       env->total_states++;
+       env->peak_states++;
 
        /* add new state to the head of linked list */
        new = &new_sl->state;
@@ -6214,8 +6363,7 @@ static int do_check(struct bpf_verifier_env *env)
        struct bpf_verifier_state *state;
        struct bpf_insn *insns = env->prog->insnsi;
        struct bpf_reg_state *regs;
-       int insn_cnt = env->prog->len, i;
-       int insn_processed = 0;
+       int insn_cnt = env->prog->len;
        bool do_print_state = false;
 
        env->prev_linfo = NULL;
@@ -6250,10 +6398,10 @@ static int do_check(struct bpf_verifier_env *env)
                insn = &insns[env->insn_idx];
                class = BPF_CLASS(insn->code);
 
-               if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
+               if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
                        verbose(env,
                                "BPF program is too large. Processed %d insn\n",
-                               insn_processed);
+                               env->insn_processed);
                        return -E2BIG;
                }
 
@@ -6262,7 +6410,7 @@ static int do_check(struct bpf_verifier_env *env)
                        return err;
                if (err == 1) {
                        /* found equivalent state, can prune the search */
-                       if (env->log.level) {
+                       if (env->log.level & BPF_LOG_LEVEL) {
                                if (do_print_state)
                                        verbose(env, "\nfrom %d to %d%s: safe\n",
                                                env->prev_insn_idx, env->insn_idx,
@@ -6280,8 +6428,9 @@ static int do_check(struct bpf_verifier_env *env)
                if (need_resched())
                        cond_resched();
 
-               if (env->log.level > 1 || (env->log.level && do_print_state)) {
-                       if (env->log.level > 1)
+               if (env->log.level & BPF_LOG_LEVEL2 ||
+                   (env->log.level & BPF_LOG_LEVEL && do_print_state)) {
+                       if (env->log.level & BPF_LOG_LEVEL2)
                                verbose(env, "%d:", env->insn_idx);
                        else
                                verbose(env, "\nfrom %d to %d%s:",
@@ -6292,7 +6441,7 @@ static int do_check(struct bpf_verifier_env *env)
                        do_print_state = false;
                }
 
-               if (env->log.level) {
+               if (env->log.level & BPF_LOG_LEVEL) {
                        const struct bpf_insn_cbs cbs = {
                                .cb_print       = verbose,
                                .private_data   = env,
@@ -6557,16 +6706,6 @@ process_bpf_exit:
                env->insn_idx++;
        }
 
-       verbose(env, "processed %d insns (limit %d), stack depth ",
-               insn_processed, BPF_COMPLEXITY_LIMIT_INSNS);
-       for (i = 0; i < env->subprog_cnt; i++) {
-               u32 depth = env->subprog_info[i].stack_depth;
-
-               verbose(env, "%d", depth);
-               if (i + 1 < env->subprog_cnt)
-                       verbose(env, "+");
-       }
-       verbose(env, "\n");
        env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
        return 0;
 }
@@ -6829,8 +6968,13 @@ static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 of
        struct bpf_prog *new_prog;
 
        new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
-       if (!new_prog)
+       if (IS_ERR(new_prog)) {
+               if (PTR_ERR(new_prog) == -ERANGE)
+                       verbose(env,
+                               "insn %d cannot be patched due to 16-bit range\n",
+                               env->insn_aux_data[off].orig_idx);
                return NULL;
+       }
        if (adjust_insn_aux_data(env, new_prog->len, off, len))
                return NULL;
        adjust_subprog_starts(env, off, len);
@@ -7772,6 +7916,14 @@ static void free_states(struct bpf_verifier_env *env)
        struct bpf_verifier_state_list *sl, *sln;
        int i;
 
+       sl = env->free_list;
+       while (sl) {
+               sln = sl->next;
+               free_verifier_state(&sl->state, false);
+               kfree(sl);
+               sl = sln;
+       }
+
        if (!env->explored_states)
                return;
 
@@ -7787,12 +7939,37 @@ static void free_states(struct bpf_verifier_env *env)
                        }
        }
 
-       kfree(env->explored_states);
+       kvfree(env->explored_states);
+}
+
+static void print_verification_stats(struct bpf_verifier_env *env)
+{
+       int i;
+
+       if (env->log.level & BPF_LOG_STATS) {
+               verbose(env, "verification time %lld usec\n",
+                       div_u64(env->verification_time, 1000));
+               verbose(env, "stack depth ");
+               for (i = 0; i < env->subprog_cnt; i++) {
+                       u32 depth = env->subprog_info[i].stack_depth;
+
+                       verbose(env, "%d", depth);
+                       if (i + 1 < env->subprog_cnt)
+                               verbose(env, "+");
+               }
+               verbose(env, "\n");
+       }
+       verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
+               "total_states %d peak_states %d mark_read %d\n",
+               env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
+               env->max_states_per_insn, env->total_states,
+               env->peak_states, env->longest_mark_read_walk);
 }
 
 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
              union bpf_attr __user *uattr)
 {
+       u64 start_time = ktime_get_ns();
        struct bpf_verifier_env *env;
        struct bpf_verifier_log *log;
        int i, len, ret = -EINVAL;
@@ -7834,8 +8011,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 
                ret = -EINVAL;
                /* log attributes have to be sane */
-               if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
-                   !log->level || !log->ubuf)
+               if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
+                   !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
                        goto err_unlock;
        }
 
@@ -7858,7 +8035,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
                        goto skip_full_check;
        }
 
-       env->explored_states = kcalloc(env->prog->len,
+       env->explored_states = kvcalloc(env->prog->len,
                                       sizeof(struct bpf_verifier_state_list *),
                                       GFP_USER);
        ret = -ENOMEM;
@@ -7916,6 +8093,9 @@ skip_full_check:
        if (ret == 0)
                ret = fixup_call_args(env);
 
+       env->verification_time = ktime_get_ns() - start_time;
+       print_verification_stats(env);
+
        if (log->level && bpf_verifier_log_full(log))
                ret = -ENOSPC;
        if (log->level && !log->ubuf) {