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checker: restrict too deep recursion, to prevent stackoverflows on windows 

For v itself, the nesting levels do not exceed 15, so a limit of 40 seems reasonable.
pull/13507/head
Delyan Angelov 2022-02-17 10:04:01 +02:00
parent 842fd7a27e
commit 901a4d8b84
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GPG Key ID: 66886C0F12D595ED
1 changed files with 20 additions and 3 deletions
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23
vlib/v/checker/checker.v
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@ -17,6 +17,13 @@ const int_min = int(0x80000000)
const int_max = int(0x7FFFFFFF)
// prevent stack overflows by restricting too deep recursion:
const expr_level_cutoff_limit = 40
const stmt_level_cutoff_limit = 40
const iface_level_cutoff_limit = 40
const (
valid_comptime_if_os = ['windows', 'ios', 'macos', 'mach', 'darwin', 'hpux', 'gnu',
'qnx', 'linux', 'freebsd', 'openbsd', 'netbsd', 'bsd', 'dragonfly', 'android', 'solaris',
@ -488,7 +495,7 @@ pub fn (mut c Checker) sum_type_decl(node ast.SumTypeDecl) {
pub fn (mut c Checker) expand_iface_embeds(idecl &ast.InterfaceDecl, level int, iface_embeds []ast.InterfaceEmbedding) []ast.InterfaceEmbedding {
// eprintln('> expand_iface_embeds: idecl.name: $idecl.name | level: $level | iface_embeds.len: $iface_embeds.len')
if level > 100 {
if level > checker.iface_level_cutoff_limit {
c.error('too many interface embedding levels: $level, for interface `$idecl.name`',
idecl.pos)
return []
@ -2310,6 +2317,17 @@ fn (mut c Checker) stmts(stmts []ast.Stmt) {
// `x := if cond { stmt1 stmt2 ExprStmt } else { stmt2 stmt3 ExprStmt }`,
// `x := match expr { Type1 { stmt1 stmt2 ExprStmt } else { stmt2 stmt3 ExprStmt }`.
fn (mut c Checker) stmts_ending_with_expression(stmts []ast.Stmt) {
if stmts.len == 0 {
c.scope_returns = false
c.expected_type = ast.void_type
return
}
if c.stmt_level > checker.stmt_level_cutoff_limit {
c.scope_returns = false
c.expected_type = ast.void_type
c.error('checker: too many stmt levels: $c.stmt_level ', stmts[0].pos)
return
}
mut unreachable := token.Pos{
line_nr: -1
}
@ -2360,8 +2378,7 @@ pub fn (mut c Checker) expr(node ast.Expr) ast.Type {
c.expr_level--
}
// c.expr_level set to 150 so that stack overflow does not occur on windows
if c.expr_level > 150 {
if c.expr_level > checker.expr_level_cutoff_limit {
c.error('checker: too many expr levels: $c.expr_level ', node.pos())
return ast.void_type
}