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[njs] The maximum depth of nested functions is set to 128.

Alexander Borisov
July 15, 2021 01:36PM
details: https://hg.nginx.org/njs/rev/424dd99ada9a
branches:
changeset: 1682:424dd99ada9a
user: Alexander Borisov <alexander.borisov@nginx.com>
date: Thu Jul 15 20:32:44 2021 +0300
description:
The maximum depth of nested functions is set to 128.

diffstat:

src/njs_generator.c | 22 +++++++++++++++++-----
src/njs_generator.h | 2 ++
src/test/njs_unit_test.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 49 insertions(+), 5 deletions(-)

diffs (126 lines):

diff -r 20dec02c7283 -r 424dd99ada9a src/njs_generator.c
--- a/src/njs_generator.c Thu Jul 15 20:32:43 2021 +0300
+++ b/src/njs_generator.c Thu Jul 15 20:32:44 2021 +0300
@@ -10,6 +10,9 @@
#include <njs_main.h>


+#define NJS_FUNCTION_MAX_DEPTH 128
+
+
typedef struct njs_generator_patch_s njs_generator_patch_t;

typedef enum {
@@ -275,7 +278,7 @@ static njs_int_t njs_generate_function_d
njs_generator_t *generator, njs_parser_node_t *node);
static njs_int_t njs_generate_function_scope(njs_vm_t *vm,
njs_function_lambda_t *lambda, njs_parser_node_t *node,
- const njs_str_t *name);
+ const njs_str_t *name, njs_uint_t depth);
static njs_int_t njs_generate_scope_end(njs_vm_t *vm,
njs_generator_t *generator, njs_parser_node_t *node);
static int64_t njs_generate_lambda_variables(njs_vm_t *vm,
@@ -3043,7 +3046,8 @@ njs_generate_function_expression(njs_vm_
return NJS_ERROR;
}

- ret = njs_generate_function_scope(vm, lambda, node, &lex_entry->name);
+ ret = njs_generate_function_scope(vm, lambda, node, &lex_entry->name,
+ generator->depth);
if (njs_slow_path(ret != NJS_OK)) {
return ret;
}
@@ -3078,7 +3082,7 @@ njs_generate_function(njs_vm_t *vm, njs_

name = module ? &njs_entry_module : &njs_entry_anonymous;

- ret = njs_generate_function_scope(vm, lambda, node, name);
+ ret = njs_generate_function_scope(vm, lambda, node, name, generator->depth);
if (njs_slow_path(ret != NJS_OK)) {
return ret;
}
@@ -3577,7 +3581,8 @@ njs_generate_function_declaration(njs_vm
return NJS_ERROR;
}

- ret = njs_generate_function_scope(vm, lambda, node, &lex_entry->name);
+ ret = njs_generate_function_scope(vm, lambda, node, &lex_entry->name,
+ generator->depth);
if (njs_slow_path(ret != NJS_OK)) {
return ret;
}
@@ -3599,7 +3604,7 @@ njs_generate_function_declaration(njs_vm

static njs_int_t
njs_generate_function_scope(njs_vm_t *vm, njs_function_lambda_t *lambda,
- njs_parser_node_t *node, const njs_str_t *name)
+ njs_parser_node_t *node, const njs_str_t *name, njs_uint_t depth)
{
njs_arr_t *arr;
njs_bool_t module;
@@ -3609,6 +3614,13 @@ njs_generate_function_scope(njs_vm_t *vm

njs_memzero(&generator, sizeof(njs_generator_t));

+ if (++depth >= NJS_FUNCTION_MAX_DEPTH) {
+ njs_range_error(vm, "Maximum function nesting depth exceeded");
+ return NJS_ERROR;
+ }
+
+ generator.depth = depth;
+
node = node->right;

code = njs_generate_scope(vm, &generator, node->scope, name);
diff -r 20dec02c7283 -r 424dd99ada9a src/njs_generator.h
--- a/src/njs_generator.h Thu Jul 15 20:32:43 2021 +0300
+++ b/src/njs_generator.h Thu Jul 15 20:32:44 2021 +0300
@@ -35,6 +35,8 @@ struct njs_generator_s {

/* Parsing Function() or eval(). */
uint8_t runtime; /* 1 bit */
+
+ njs_uint_t depth;
};


diff -r 20dec02c7283 -r 424dd99ada9a src/test/njs_unit_test.c
--- a/src/test/njs_unit_test.c Thu Jul 15 20:32:43 2021 +0300
+++ b/src/test/njs_unit_test.c Thu Jul 15 20:32:44 2021 +0300
@@ -9590,6 +9590,36 @@ static njs_unit_test_t njs_test[] =
"fn(1); arr"),
njs_str("1,2,3,4,5,6") },

+ /* Function nesting depth. */
+
+ { njs_str("() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => 1"),
+ njs_str("[object Function]") },
+
+ { njs_str("() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => () => () => () => () =>"
+ "() => () => () => () => () => () => () => 1"),
+ njs_str("RangeError: Maximum function nesting depth exceeded") },
+
/* Recursive factorial. */

{ njs_str("function f(a) {"
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[njs] The maximum depth of nested functions is set to 128.

Alexander Borisov 71 July 15, 2021 01:36PM



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