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11506 smatch resync

@@ -30,11 +30,11 @@
 static int my_call_id;
 
 STATE(called);
 static bool func_gets_user_data;
 
-static const char * kstr_funcs[] = {
+static const char *kstr_funcs[] = {
         "kstrtoull", "kstrtoll", "kstrtoul", "kstrtol", "kstrtouint",
         "kstrtoint", "kstrtou64", "kstrtos64", "kstrtou32", "kstrtos32",
         "kstrtou16", "kstrtos16", "kstrtou8", "kstrtos8", "kstrtoull_from_user"
         "kstrtoll_from_user", "kstrtoul_from_user", "kstrtol_from_user",
         "kstrtouint_from_user", "kstrtoint_from_user", "kstrtou16_from_user",

@@ -43,14 +43,17 @@
         "kstrtos32_from_user",
 };
 
 static const char *returns_user_data[] = {
         "simple_strtol", "simple_strtoll", "simple_strtoul", "simple_strtoull",
-        "kvm_register_read", "nlmsg_data", "nla_data", "memdup_user",
-        "kmap_atomic", "skb_network_header",
+        "kvm_register_read",
 };
 
+static const char *returns_pointer_to_user_data[] = {
+        "nlmsg_data", "nla_data", "memdup_user", "kmap_atomic", "skb_network_header",
+};
+
 static void set_points_to_user_data(struct expression *expr);
 
 static struct stree *start_states;
 static struct stree_stack *saved_stack;
 static void save_start_states(struct statement *stmt)

@@ -82,65 +85,104 @@
 
 static void pre_merge_hook(struct sm_state *sm)
 {
         struct smatch_state *user;
         struct smatch_state *extra;
+        struct smatch_state *state;
         struct range_list *rl;
         sval_t dummy;
         sval_t sval_100;
 
         sval_100.value = 100;
         sval_100.type = &int_ctype;
 
-        user = get_state(my_id, sm->name, sm->sym);
-        if (!user)
+        user = __get_state(my_id, sm->name, sm->sym);
+        if (!user || !estate_rl(user))
                 return;
-        if (!__in_function_def && !estate_rl(sm->state)) {
-                /*
-                 * If the one side is capped and the other side is empty then
-                 * let's just mark it as not-user data because the information
-                 * isn't going to be useful.  How this looks is:
-                 *
-                 * if (user_var > trusted)
-                 *      user_var = trusted;  <-- empty state
-                 * else
-                 *      <-- capped
-                 *
-                 * The problem is that sometimes things are capped to a literal
-                 * and we'd like to keep the state in that case...  Ugh.  I've
-                 * added a check which assumes that everything less than 100 is
-                 * probably capped against a literal.
-                 *
-                 */
-                if (is_capped_var_sym(sm->name, sm->sym) &&
-                    sval_cmp(estate_max(user), sval_100) > 0)
-                        set_state(my_id, sm->name, sm->sym, alloc_estate_empty());
+        extra = __get_state(SMATCH_EXTRA, sm->name, sm->sym);
+        if (!extra)
                 return;
-        }
-        extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
-        if (!extra || !estate_rl(extra))
-                return;
         rl = rl_intersection(estate_rl(user), estate_rl(extra));
         if (rl_to_sval(rl, &dummy))
                 rl = NULL;
-        set_state(my_id, sm->name, sm->sym, alloc_estate_rl(clone_rl(rl)));
+        state = alloc_estate_rl(clone_rl(rl));
+        if (estate_capped(user) || is_capped_var_sym(sm->name, sm->sym))
+                estate_set_capped(state);
+        set_state(my_id, sm->name, sm->sym, state);
 }
 
 static void extra_nomod_hook(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
 {
-        struct smatch_state *user;
+        struct smatch_state *user, *new;
         struct range_list *rl;
 
-        user = get_state(my_id, name, sym);
+        user = __get_state(my_id, name, sym);
         if (!user)
                 return;
         rl = rl_intersection(estate_rl(user), estate_rl(state));
         if (rl_equiv(rl, estate_rl(user)))
                 return;
-        set_state(my_id, name, sym, alloc_estate_rl(rl));
+        new = alloc_estate_rl(rl);
+        if (estate_capped(user))
+                estate_set_capped(new);
+        set_state(my_id, name, sym, new);
 }
 
+static bool binop_capped(struct expression *expr)
+{
+        struct range_list *left_rl;
+        int comparison;
+
+        if (expr->op == '-' && get_user_rl(expr->left, &left_rl)) {
+                if (user_rl_capped(expr->left))
+                        return true;
+                comparison = get_comparison(expr->left, expr->right);
+                if (comparison && show_special(comparison)[0] == '>')
+                        return true;
+                return false;
+        }
+
+        if (expr->op == '&' || expr->op == '%') {
+                if (is_capped(expr->left) || is_capped(expr->right))
+                        return true;
+                if (user_rl_capped(expr->left) || user_rl_capped(expr->right))
+                        return true;
+                return false;
+        }
+
+        if (user_rl_capped(expr->left) &&
+            user_rl_capped(expr->right))
+                return true;
+        return false;
+}
+
+bool user_rl_capped(struct expression *expr)
+{
+        struct smatch_state *state;
+        struct range_list *rl;
+        sval_t sval;
+
+        expr = strip_expr(expr);
+        if (!expr)
+                return false;
+        if (get_value(expr, &sval))
+                return true;
+        if (expr->type == EXPR_BINOP)
+                return binop_capped(expr);
+        if ((expr->type == EXPR_PREOP || expr->type == EXPR_POSTOP) &&
+            (expr->op == SPECIAL_INCREMENT || expr->op == SPECIAL_DECREMENT))
+                return user_rl_capped(expr->unop);
+        state = get_state_expr(my_id, expr);
+        if (state)
+                return estate_capped(state);
+
+        if (get_user_rl(expr, &rl))
+                return false;  /* uncapped user data */
+
+        return true;  /* not actually user data */
+}
+
 static void tag_inner_struct_members(struct expression *expr, struct symbol *member)
 {
         struct expression *edge_member;
         struct symbol *base = get_real_base_type(member);
         struct symbol *tmp;

@@ -345,10 +387,26 @@
                 return 0;
 
         return 1;
 }
 
+static bool is_points_to_user_data_fn(struct expression *expr)
+{
+        int i;
+
+        expr = strip_expr(expr);
+        if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||
+            !expr->fn->symbol)
+                return false;
+        expr = expr->fn;
+        for (i = 0; i < ARRAY_SIZE(returns_pointer_to_user_data); i++) {
+                if (sym_name_is(returns_pointer_to_user_data[i], expr))
+                        return true;
+        }
+        return false;
+}
+
 static int get_rl_from_function(struct expression *expr, struct range_list **rl)
 {
         int i;
 
         if (expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL ||

@@ -376,10 +434,12 @@
         expr = strip_expr(expr);
         if (!expr)
                 return 0;
         if (is_skb_data(expr))
                 return 1;
+        if (is_points_to_user_data_fn(expr))
+                return 1;
         if (get_rl_from_function(expr, &rl))
                 return 1;
 
         if (expr->type == EXPR_BINOP && expr->op == '+') {
                 if (points_to_user_data(expr->left))

@@ -391,11 +451,11 @@
 
         name = expr_to_var_sym(expr, &sym);
         if (!name || !sym)
                 goto free;
         snprintf(buf, sizeof(buf), "*%s", name);
-        state = get_state(my_id, buf, sym);
+        state = __get_state(my_id, buf, sym);
         if (state && estate_rl(state))
                 ret = 1;
 free:
         free_string(name);
         return ret;

@@ -404,16 +464,22 @@
 static void set_points_to_user_data(struct expression *expr)
 {
         char *name;
         struct symbol *sym;
         char buf[256];
+        struct symbol *type;
 
         name = expr_to_var_sym(expr, &sym);
         if (!name || !sym)
                 goto free;
         snprintf(buf, sizeof(buf), "*%s", name);
-        set_state(my_id, buf, sym, alloc_estate_whole(&llong_ctype));
+        type = get_type(expr);
+        if (type && type->type == SYM_PTR)
+                type = get_real_base_type(type);
+        if (!type || type->type != SYM_BASETYPE)
+                type = &llong_ctype;
+        set_state(my_id, buf, sym, alloc_estate_whole(type));
 free:
         free_string(name);
 }
 
 static int comes_from_skb_data(struct expression *expr)

@@ -487,28 +553,81 @@
 free:
         free_string(name);
         return ret;
 }
 
+static bool handle_op_assign(struct expression *expr)
+{
+        struct expression *binop_expr;
+        struct smatch_state *state;
+        struct range_list *rl;
+
+        switch (expr->op) {
+        case SPECIAL_ADD_ASSIGN:
+        case SPECIAL_SUB_ASSIGN:
+        case SPECIAL_AND_ASSIGN:
+        case SPECIAL_MOD_ASSIGN:
+        case SPECIAL_SHL_ASSIGN:
+        case SPECIAL_SHR_ASSIGN:
+        case SPECIAL_OR_ASSIGN:
+        case SPECIAL_XOR_ASSIGN:
+        case SPECIAL_MUL_ASSIGN:
+        case SPECIAL_DIV_ASSIGN:
+                binop_expr = binop_expression(expr->left,
+                                              op_remove_assign(expr->op),
+                                              expr->right);
+                if (!get_user_rl(binop_expr, &rl))
+                        return true;
+
+                rl = cast_rl(get_type(expr->left), rl);
+                state = alloc_estate_rl(rl);
+                if (user_rl_capped(binop_expr))
+                        estate_set_capped(state);
+                set_state_expr(my_id, expr->left, state);
+                return true;
+        }
+        return false;
+}
+
 static void match_assign(struct expression *expr)
 {
         struct range_list *rl;
+        static struct expression *handled;
+        struct smatch_state *state;
+        struct expression *faked;
 
+        faked = get_faked_expression();
+        if (faked && faked == handled)
+                return;
         if (is_fake_call(expr->right))
                 goto clear_old_state;
         if (handle_get_user(expr))
                 return;
-        if (points_to_user_data(expr->right))
+        if (points_to_user_data(expr->right)) {
+                handled = expr;
                 set_points_to_user_data(expr->left);
+        }
         if (handle_struct_assignment(expr))
                 return;
 
+        if (handle_op_assign(expr))
+                return;
+        if (expr->op != '=')
+                goto clear_old_state;
+
+        /* Handled by DB code */
+        if (expr->right->type == EXPR_CALL || __in_fake_parameter_assign)
+                return;
+
         if (!get_user_rl(expr->right, &rl))
                 goto clear_old_state;
 
         rl = cast_rl(get_type(expr->left), rl);
-        set_state_expr(my_id, expr->left, alloc_estate_rl(rl));
+        state = alloc_estate_rl(rl);
+        if (user_rl_capped(expr->right))
+                estate_set_capped(state);
+        set_state_expr(my_id, expr->left, state);
 
         return;
 
 clear_old_state:
         if (get_state_expr(my_id, expr->left))

@@ -536,65 +655,119 @@
                                 expr->op == SPECIAL_EQUAL ? alloc_estate_empty() : NULL,
                                 expr->op == SPECIAL_EQUAL ? NULL : alloc_estate_empty());
         }
 }
 
-static void handle_unsigned_lt_gt(struct expression *expr)
+static struct range_list *strip_negatives(struct range_list *rl)
 {
+        sval_t min = rl_min(rl);
+        sval_t minus_one;
+        sval_t over;
+        sval_t max = sval_type_max(rl_type(rl));
+
+        minus_one.type = rl_type(rl);
+        minus_one.value = INT_MAX + 1ULL;
+        over.type = rl_type(rl);
+        over.value = -1;
+
+        if (!rl)
+                return NULL;
+
+        if (type_unsigned(rl_type(rl)) && type_bits(rl_type(rl)) > 31)
+                return remove_range(rl, over, max);
+
+        return remove_range(rl, min, minus_one);
+}
+
+static void handle_compare(struct expression *expr)
+{
+        struct expression  *left, *right;
+        struct range_list *left_rl = NULL;
+        struct range_list *right_rl = NULL;
+        struct range_list *user_rl;
+        struct smatch_state *capped_state;
+        struct smatch_state *left_true = NULL;
+        struct smatch_state *left_false = NULL;
+        struct smatch_state *right_true = NULL;
+        struct smatch_state *right_false = NULL;
         struct symbol *type;
-        struct range_list *left;
-        struct range_list *right;
-        struct range_list *non_negative;
-        sval_t min, minus_one;
+        sval_t sval;
 
+        left = strip_expr(expr->left);
+        right = strip_expr(expr->right);
+
+        while (left->type == EXPR_ASSIGNMENT)
+                left = strip_expr(left->left);
+
         /*
-         * conditions are mostly handled by smatch_extra.c.  The special case
-         * here is that say you have if (user_int < unknown_u32) {
-         * In Smatch extra we say that, We have no idea what value
-         * unknown_u32 is so the only thin we can say for sure is that
-         * user_int is not -1 (UINT_MAX).  But in check_user_data2.c we should
-         * assume that unless unknown_u32 is user data, it's probably less than
-         * INT_MAX.
+         * Conditions are mostly handled by smatch_extra.c, but there are some
+         * times where the exact values are not known so we can't do that.
          *
+         * Normally, we might consider using smatch_capped.c to supliment smatch
+         * extra but that doesn't work when we merge unknown uncapped kernel
+         * data with unknown capped user data.  The result is uncapped user
+         * data.  We need to keep it separate and say that the user data is
+         * capped.  In the past, I would have marked this as just regular
+         * kernel data (not user data) but we can't do that these days because
+         * we need to track user data for Spectre.
+         *
+         * The other situation which we have to handle is when we do have an
+         * int and we compare against an unknown unsigned kernel variable.  In
+         * that situation we assume that the kernel data is less than INT_MAX.
+         * Otherwise then we get all sorts of array underflow false positives.
+         *
          */
 
-        type = get_type(expr);
-        if (!type_unsigned(type))
+        /* Handled in smatch_extra.c */
+        if (get_implied_value(left, &sval) ||
+            get_implied_value(right, &sval))
                 return;
 
-        /*
-         * Assume if (user < trusted) { ... because I am lazy and because this
-         * is the correct way to write code.
-         */
-        if (!get_user_rl(expr->left, &left))
+        get_user_rl(left, &left_rl);
+        get_user_rl(right, &right_rl);
+
+        /* nothing to do */
+        if (!left_rl && !right_rl)
                 return;
-        if (get_user_rl(expr->right, &right))
+        /* if both sides are user data that's not a good limit */
+        if (left_rl && right_rl)
                 return;
 
-        if (!sval_is_negative(rl_min(left)))
-                return;
-        min = rl_min(left);
-        minus_one.type = rl_type(left);
-        minus_one.value = -1;
-        non_negative = remove_range(left, min, minus_one);
+        if (left_rl)
+                user_rl = left_rl;
+        else
+                user_rl = right_rl;
 
+        type = get_type(expr);
+        if (type_unsigned(type))
+                user_rl = strip_negatives(user_rl);
+        capped_state = alloc_estate_rl(user_rl);
+        estate_set_capped(capped_state);
+
         switch (expr->op) {
         case '<':
         case SPECIAL_UNSIGNED_LT:
         case SPECIAL_LTE:
         case SPECIAL_UNSIGNED_LTE:
-                set_true_false_states_expr(my_id, expr->left,
-                                           alloc_estate_rl(non_negative), NULL);
+                if (left_rl)
+                        left_true = capped_state;
+                else
+                        right_false = capped_state;
                 break;
         case '>':
         case SPECIAL_UNSIGNED_GT:
         case SPECIAL_GTE:
         case SPECIAL_UNSIGNED_GTE:
-                set_true_false_states_expr(my_id, expr->left,
-                                           NULL, alloc_estate_rl(non_negative));
+                if (left_rl)
+                        left_false = capped_state;
+                else
+                        right_true = capped_state;
                 break;
         }
+
+        set_true_false_states_expr(my_id, left, left_true, left_false);
+        set_true_false_states_expr(my_id, right, right_true, right_false);
 }
 
 static void match_condition(struct expression *expr)
 {
         if (expr->type != EXPR_COMPARE)

@@ -604,11 +777,11 @@
             expr->op == SPECIAL_NOTEQUAL) {
                 handle_eq_noteq(expr);
                 return;
         }
 
-        handle_unsigned_lt_gt(expr);
+        handle_compare(expr);
 }
 
 static void match_user_assign_function(const char *fn, struct expression *expr, void *unused)
 {
         tag_as_user_data(expr->left);

@@ -652,42 +825,10 @@
                 return 1;
         }
         return 0;
 }
 
-struct db_info {
-        struct range_list *rl;
-        struct expression *call;
-};
-static int returned_rl_callback(void *_info, int argc, char **argv, char **azColName)
-{
-        struct db_info *db_info = _info;
-        struct range_list *rl;
-        char *return_ranges = argv[0];
-        char *user_ranges = argv[1];
-        struct expression *arg;
-        int comparison;
-
-        if (argc != 2)
-                return 0;
-
-        call_results_to_rl(db_info->call, get_type(db_info->call), user_ranges, &rl);
-        if (str_to_comparison_arg(return_ranges, db_info->call, &comparison, &arg) &&
-            comparison == SPECIAL_EQUAL) {
-                struct range_list *orig_rl;
-
-                if (!get_user_rl(arg, &orig_rl))
-                        return 0;
-                rl = rl_intersection(rl, orig_rl);
-                if (!rl)
-                        return 0;
-        }
-        db_info->rl = rl_union(db_info->rl, rl);
-
-        return 0;
-}
-
 static int has_user_data(struct symbol *sym)
 {
         struct sm_state *tmp;
 
         FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {

@@ -713,54 +854,41 @@
         return 0;
 }
 
 static int db_returned_user_rl(struct expression *call, struct range_list **rl)
 {
-        struct db_info db_info = {};
+        struct smatch_state *state;
+        char buf[48];
 
-        /* for function pointers assume everything is used */
-        if (call->fn->type != EXPR_SYMBOL)
-                return 0;
         if (is_fake_call(call))
                 return 0;
-
-        db_info.call = call;
-        run_sql(&returned_rl_callback, &db_info,
-                "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
-                get_static_filter(call->fn->symbol), USER_DATA3_SET);
-        if (db_info.rl) {
-                func_gets_user_data = true;
-                *rl = db_info.rl;
-                return 1;
-        }
-
-        run_sql(&returned_rl_callback, &db_info,
-                "select return, value from return_states where %s and type = %d and parameter = -1 and key = '$';",
-                get_static_filter(call->fn->symbol), USER_DATA3);
-        if (db_info.rl) {
-                if (!we_pass_user_data(call))
+        snprintf(buf, sizeof(buf), "return %p", call);
+        state = get_state(my_id, buf, NULL);
+        if (!state || !estate_rl(state))
                         return 0;
-                *rl = db_info.rl;
+        *rl = estate_rl(state);
                 return 1;
-        }
-
-        return 0;
 }
 
 struct stree *get_user_stree(void)
 {
         return get_all_states_stree(my_id);
 }
 
 static int user_data_flag;
 static int no_user_data_flag;
-static struct range_list *var_user_rl(struct expression *expr)
+struct range_list *var_user_rl(struct expression *expr)
 {
         struct smatch_state *state;
         struct range_list *rl;
         struct range_list *absolute_rl;
 
+        if (expr->type == EXPR_PREOP && expr->op == '&') {
+                no_user_data_flag = 1;
+                return NULL;
+        }
+
         if (expr->type == EXPR_BINOP && expr->op == '%') {
                 struct range_list *left, *right;
 
                 if (!get_user_rl(expr->right, &right))
                         return NULL;

@@ -767,11 +895,11 @@
                 get_absolute_rl(expr->left, &left);
                 rl = rl_binop(left, '%', right);
                 goto found;
         }
 
-        if (!option_spammy && expr->type == EXPR_BINOP && expr->op == '/') {
+        if (expr->type == EXPR_BINOP && expr->op == '/') {
                 struct range_list *left = NULL;
                 struct range_list *right = NULL;
                 struct range_list *abs_right;
 
                 /*

@@ -837,37 +965,41 @@
         user_data_flag = 1;
         absolute_rl = var_to_absolute_rl(expr);
         return clone_rl(rl_intersection(rl, absolute_rl));
 }
 
+static bool is_ptr_subtract(struct expression *expr)
+{
+        expr = strip_expr(expr);
+        if (!expr)
+                return false;
+        if (expr->type == EXPR_BINOP && expr->op == '-' &&
+            type_is_ptr(get_type(expr->left))) {
+                return true;
+        }
+        return false;
+}
+
 int get_user_rl(struct expression *expr, struct range_list **rl)
 {
+        if (is_ptr_subtract(expr))
+                return 0;
+
         user_data_flag = 0;
         no_user_data_flag = 0;
         custom_get_absolute_rl(expr, &var_user_rl, rl);
         if (!user_data_flag || no_user_data_flag)
                 *rl = NULL;
 
         return !!*rl;
 }
 
-int get_user_rl_spammy(struct expression *expr, struct range_list **rl)
-{
-        int ret;
-
-        option_spammy++;
-        ret = get_user_rl(expr, rl);
-        option_spammy--;
-
-        return ret;
-}
-
 int is_user_rl(struct expression *expr)
 {
         struct range_list *tmp;
 
-        return get_user_rl_spammy(expr, &tmp);
+        return !!get_user_rl(expr, &tmp);
 }
 
 int get_user_rl_var_sym(const char *name, struct symbol *sym, struct range_list **rl)
 {
         struct smatch_state *state;

@@ -878,27 +1010,39 @@
                 return 1;
         }
         return 0;
 }
 
-static void match_call_info(struct expression *expr)
+static char *get_user_rl_str(struct expression *expr, struct symbol *type)
 {
         struct range_list *rl;
+        static char buf[64];
+
+        if (!get_user_rl(expr, &rl))
+                return NULL;
+        rl = cast_rl(type, rl);
+        snprintf(buf, sizeof(buf), "%s%s",
+                 show_rl(rl), user_rl_capped(expr) ? "[c]" : "");
+        return buf;
+}
+
+static void match_call_info(struct expression *expr)
+{
         struct expression *arg;
         struct symbol *type;
-        int i = 0;
+        char *str;
+        int i;
 
         i = -1;
         FOR_EACH_PTR(expr->args, arg) {
                 i++;
                 type = get_arg_type(expr->fn, i);
-
-                if (!get_user_rl(arg, &rl))
+                str = get_user_rl_str(arg, type);
+                if (!str)
                         continue;
 
-                rl = cast_rl(type, rl);
-                sql_insert_caller_info(expr, USER_DATA3, i, "$", show_rl(rl));
+                sql_insert_caller_info(expr, USER_DATA, i, "$", str);
         } END_FOR_EACH_PTR(arg);
 }
 
 static int is_struct_ptr(struct symbol *sym)
 {

@@ -918,10 +1062,11 @@
 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
 {
         struct smatch_state *state;
         struct range_list *rl;
         struct symbol *type;
+        char buf[64];
 
         /*
          * Smatch uses a hack where if we get an unsigned long we say it's
          * both user data and it points to user data.  But if we pass it to a
          * function which takes an int, then it's just user data.  There's not

@@ -937,45 +1082,106 @@
 
         if (strcmp(printed_name, "*$") == 0 &&
             is_struct_ptr(sm->sym))
                 return;
 
-        state = get_state(SMATCH_EXTRA, sm->name, sm->sym);
+        state = __get_state(SMATCH_EXTRA, sm->name, sm->sym);
         if (!state || !estate_rl(state))
                 rl = estate_rl(sm->state);
         else
                 rl = rl_intersection(estate_rl(sm->state), estate_rl(state));
 
-        sql_insert_caller_info(call, USER_DATA3, param, printed_name, show_rl(rl));
+        if (!rl)
+                return;
+
+        snprintf(buf, sizeof(buf), "%s%s", show_rl(rl),
+                 estate_capped(sm->state) ? "[c]" : "");
+        sql_insert_caller_info(call, USER_DATA, param, printed_name, buf);
 }
 
+static void db_param_set(struct expression *expr, int param, char *key, char *value)
+{
+        struct expression *arg;
+        char *name;
+        struct symbol *sym;
+        struct smatch_state *state;
+
+        while (expr->type == EXPR_ASSIGNMENT)
+                expr = strip_expr(expr->right);
+        if (expr->type != EXPR_CALL)
+                return;
+
+        arg = get_argument_from_call_expr(expr->args, param);
+        if (!arg)
+                return;
+        name = get_variable_from_key(arg, key, &sym);
+        if (!name || !sym)
+                goto free;
+
+        state = get_state(my_id, name, sym);
+        if (!state)
+                goto free;
+
+        set_state(my_id, name, sym, alloc_estate_empty());
+free:
+        free_string(name);
+}
+
+static bool param_data_capped(const char *value)
+{
+        if (strstr(value, ",c") || strstr(value, "[c"))
+                return true;
+        return false;
+}
+
 static void set_param_user_data(const char *name, struct symbol *sym, char *key, char *value)
 {
         struct range_list *rl = NULL;
         struct smatch_state *state;
+        struct expression *expr;
         struct symbol *type;
         char fullname[256];
+        char *key_orig = key;
+        bool add_star = false;
 
-        if (strcmp(key, "*$") == 0)
-                snprintf(fullname, sizeof(fullname), "*%s", name);
-        else if (strncmp(key, "$", 1) == 0)
-                snprintf(fullname, 256, "%s%s", name, key + 1);
-        else
-                return;
+        if (strcmp(key, "**$") == 0) {
+                snprintf(fullname, sizeof(fullname), "**%s", name);
+        } else {
+                if (key[0] == '*') {
+                        add_star = true;
+                        key++;
+                }
 
-        type = get_member_type_from_key(symbol_expression(sym), key);
+                snprintf(fullname, 256, "%s%s%s", add_star ? "*" : "", name, key + 1);
+        }
 
-        /* if the caller passes a void pointer with user data */
-        if (strcmp(key, "*$") == 0 && type && type != &void_ctype) {
-                struct expression *expr = symbol_expression(sym);
+        expr = symbol_expression(sym);
+        type = get_member_type_from_key(expr, key_orig);
 
-                tag_as_user_data(expr);
-                set_points_to_user_data(expr);
+        /*
+         * Say this function takes a struct ponter but the caller passes
+         * this_function(skb->data).  We have two options, we could pass *$
+         * as user data or we could pass foo->bar, foo->baz as user data.
+         * The second option is easier to implement so we do that.
+         *
+         */
+        if (strcmp(key_orig, "*$") == 0) {
+                struct symbol *tmp = type;
+
+                while (tmp && tmp->type == SYM_PTR)
+                        tmp = get_real_base_type(tmp);
+
+                if (tmp && (tmp->type == SYM_STRUCT || tmp->type == SYM_UNION)) {
+                        tag_as_user_data(symbol_expression(sym));
                 return;
         }
+        }
+
         str_to_rl(type, value, &rl);
         state = alloc_estate_rl(rl);
+        if (param_data_capped(value) || is_capped(expr))
+                estate_set_capped(state);
         set_state(my_id, fullname, sym, state);
 }
 
 static void set_called(const char *name, struct symbol *sym, char *key, char *value)
 {

@@ -1010,12 +1216,29 @@
         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
         } END_FOR_EACH_PTR(arg);
 }
 
+static void store_user_data_return(struct expression *expr, char *key, char *value)
+{
+        struct range_list *rl;
+        struct symbol *type;
+        char buf[48];
+
+        if (strcmp(key, "$") != 0)
+                return;
+
+        type = get_type(expr);
+        snprintf(buf, sizeof(buf), "return %p", expr);
+        call_results_to_rl(expr, type, value, &rl);
+
+        set_state(my_id, buf, NULL, alloc_estate_rl(rl));
+}
+
 static void set_to_user_data(struct expression *expr, char *key, char *value)
 {
+        struct smatch_state *state;
         char *name;
         struct symbol *sym;
         struct symbol *type;
         struct range_list *rl = NULL;
 

@@ -1024,14 +1247,16 @@
         if (!name || !sym)
                 goto free;
 
         call_results_to_rl(expr, type, value, &rl);
 
-        set_state(my_id, name, sym, alloc_estate_rl(rl));
+        state = alloc_estate_rl(rl);
+        if (param_data_capped(value))
+                estate_set_capped(state);
+        set_state(my_id, name, sym, state);
 free:
         free_string(name);
-
 }
 
 static void returns_param_user_data(struct expression *expr, int param, char *key, char *value)
 {
         struct expression *arg;

@@ -1045,12 +1270,14 @@
 
         if (!we_pass_user_data(call))
                 return;
 
         if (param == -1) {
-                if (expr->type != EXPR_ASSIGNMENT)
+                if (expr->type != EXPR_ASSIGNMENT) {
+                        store_user_data_return(expr, key, value);
                         return;
+                }
                 set_to_user_data(expr->left, key, value);
                 return;
         }
 
         arg = get_argument_from_call_expr(call->args, param);

@@ -1064,12 +1291,14 @@
         struct expression *arg;
 
         func_gets_user_data = true;
 
         if (param == -1) {
-                if (expr->type != EXPR_ASSIGNMENT)
+                if (expr->type != EXPR_ASSIGNMENT) {
+                        store_user_data_return(expr, key, value);
                         return;
+                }
                 if (strcmp(key, "*$") == 0) {
                         set_points_to_user_data(expr->left);
                         tag_as_user_data(expr->left);
                 } else {
                         set_to_user_data(expr->left, key, value);

@@ -1086,22 +1315,10 @@
         if (!arg)
                 return;
         set_to_user_data(arg, key, value);
 }
 
-static int has_empty_state(struct sm_state *sm)
-{
-        struct sm_state *tmp;
-
-        FOR_EACH_PTR(sm->possible, tmp) {
-                if (!estate_rl(tmp->state))
-                        return 1;
-        } END_FOR_EACH_PTR(tmp);
-
-        return 0;
-}
-
 static void param_set_to_user_data(int return_id, char *return_ranges, struct expression *expr)
 {
         struct sm_state *sm;
         struct smatch_state *start_state;
         struct range_list *rl;

@@ -1108,23 +1325,25 @@
         int param;
         char *return_str;
         const char *param_name;
         struct symbol *ret_sym;
         bool return_found = false;
+        bool pointed_at_found = false;
+        char buf[64];
 
         expr = strip_expr(expr);
         return_str = expr_to_str(expr);
         ret_sym = expr_to_sym(expr);
 
         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
-                if (has_empty_state(sm))
-                        continue;
-
                 param = get_param_num_from_sym(sm->sym);
                 if (param < 0)
                         continue;
 
+                if (!param_was_set_var_sym(sm->name, sm->sym))
+                        continue;
+
                 /* The logic here was that if we were passed in a user data then
                  * we don't record that.  It's like the difference between
                  * param_filter and param_set.  When I think about it, I'm not
                  * sure it actually works.  It's probably harmless because we
                  * checked earlier that we're not returning a parameter...

@@ -1138,24 +1357,19 @@
                 if (!param_name)
                         continue;
                 if (strcmp(param_name, "$") == 0)  /* The -1 param is handled after the loop */
                         continue;
 
+                snprintf(buf, sizeof(buf), "%s%s",
+                         show_rl(estate_rl(sm->state)),
+                         estate_capped(sm->state) ? "[c]" : "");
                 sql_insert_return_states(return_id, return_ranges,
-                                         func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
-                                         param, param_name, show_rl(estate_rl(sm->state)));
+                                         func_gets_user_data ? USER_DATA_SET : USER_DATA,
+                                         param, param_name, buf);
         } END_FOR_EACH_SM(sm);
 
-        if (points_to_user_data(expr)) {
-                sql_insert_return_states(return_id, return_ranges,
-                                         (is_skb_data(expr) || !func_gets_user_data) ?
-                                         USER_DATA3_SET : USER_DATA3,
-                                         -1, "*$", "");
-                goto free_string;
-        }
-
-
+        /* This if for "return foo;" where "foo->bar" is user data. */
         FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
                 if (!ret_sym)
                         break;
                 if (ret_sym != sm->sym)
                         continue;

@@ -1163,27 +1377,65 @@
                 param_name = state_name_to_param_name(sm->name, return_str);
                 if (!param_name)
                         continue;
                 if (strcmp(param_name, "$") == 0)
                         return_found = true;
+                if (strcmp(param_name, "*$") == 0)
+                        pointed_at_found = true;
+                snprintf(buf, sizeof(buf), "%s%s",
+                         show_rl(estate_rl(sm->state)),
+                         estate_capped(sm->state) ? "[c]" : "");
                 sql_insert_return_states(return_id, return_ranges,
-                                         func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
-                                         -1, param_name, show_rl(estate_rl(sm->state)));
+                                         func_gets_user_data ? USER_DATA_SET : USER_DATA,
+                                         -1, param_name, buf);
         } END_FOR_EACH_SM(sm);
 
-
+        /* This if for "return ntohl(foo);" */
         if (!return_found && get_user_rl(expr, &rl)) {
+                snprintf(buf, sizeof(buf), "%s%s",
+                         show_rl(rl), user_rl_capped(expr) ? "[c]" : "");
                 sql_insert_return_states(return_id, return_ranges,
-                                         func_gets_user_data ? USER_DATA3_SET : USER_DATA3,
-                                         -1, "$", show_rl(rl));
-                goto free_string;
+                                         func_gets_user_data ? USER_DATA_SET : USER_DATA,
+                                         -1, "$", buf);
         }
 
-free_string:
+        /*
+         * This is to handle things like return skb->data where we don't set a
+         * state for that.
+         */
+        if (!pointed_at_found && points_to_user_data(expr)) {
+                sql_insert_return_states(return_id, return_ranges,
+                                         (is_skb_data(expr) || func_gets_user_data) ?
+                                         USER_DATA_SET : USER_DATA,
+                                         -1, "*$", "s64min-s64max");
+        }
+
         free_string(return_str);
 }
 
+static void returns_param_capped(struct expression *expr, int param, char *key, char *value)
+{
+        struct smatch_state *state, *new;
+        struct symbol *sym;
+        char *name;
+
+        name = return_state_to_var_sym(expr, param, key, &sym);
+        if (!name || !sym)
+                goto free;
+
+        state = get_state(my_id, name, sym);
+        if (!state || estate_capped(state))
+                goto free;
+
+        new = clone_estate(state);
+        estate_set_capped(new);
+
+        set_state(my_id, name, sym, new);
+free:
+        free_string(name);
+}
+
 static struct int_stack *gets_data_stack;
 static void match_function_def(struct symbol *sym)
 {
         func_gets_user_data = false;
 }

@@ -1196,19 +1448,21 @@
 static void match_inline_end(struct expression *expr)
 {
         func_gets_user_data = pop_int(&gets_data_stack);
 }
 
-void register_kernel_user_data2(int id)
+void register_kernel_user_data(int id)
 {
         int i;
 
         my_id = id;
 
         if (option_project != PROJ_KERNEL)
                 return;
 
+        set_dynamic_states(my_id);
+
         add_hook(&match_function_def, FUNC_DEF_HOOK);
         add_hook(&match_inline_start, INLINE_FN_START);
         add_hook(&match_inline_end, INLINE_FN_END);
 
         add_hook(&save_start_states, AFTER_DEF_HOOK);

@@ -1236,24 +1490,25 @@
         add_function_hook("sscanf", &match_sscanf, NULL);
 
         add_hook(&match_syscall_definition, AFTER_DEF_HOOK);
 
         add_hook(&match_assign, ASSIGNMENT_HOOK);
+        select_return_states_hook(PARAM_SET, &db_param_set);
         add_hook(&match_condition, CONDITION_HOOK);
 
         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
         add_member_info_callback(my_id, struct_member_callback);
-        select_caller_info_hook(set_param_user_data, USER_DATA3);
-        select_return_states_hook(USER_DATA3, &returns_param_user_data);
-        select_return_states_hook(USER_DATA3_SET, &returns_param_user_data_set);
+        select_caller_info_hook(set_param_user_data, USER_DATA);
+        select_return_states_hook(USER_DATA, &returns_param_user_data);
+        select_return_states_hook(USER_DATA_SET, &returns_param_user_data_set);
+        select_return_states_hook(CAPPED_DATA, &returns_param_capped);
         add_split_return_callback(&param_set_to_user_data);
 }
 
-void register_kernel_user_data3(int id)
+void register_kernel_user_data2(int id)
 {
         my_call_id = id;
 
         if (option_project != PROJ_KERNEL)
                 return;
         select_caller_info_hook(set_called, INTERNAL);
 }
-