This patch fixes some incorrect behaviour of symbolic variables:
- prohibit redefining an existing symbol
- verify existance of a symbolic variable during parsing instead of evaluation
The second point makes sure we don't allow recursive definitions (var = $var),
which lead to a crash due to stack exhaustion.
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
src/parser.y | 21 ++++++++++++++++++---
tests/symbolic-define.1 | 7 +++++++
tests/symbolic-define.2 | 7 +++++++
tests/symbolic-define.3 | 6 ++++++
4 files changed, 38 insertions(+), 3 deletions(-)
create mode 100644 tests/symbolic-define.1
create mode 100644 tests/symbolic-define.2
create mode 100644 tests/symbolic-define.3
diff --git a/src/parser.y b/src/parser.y
index cc0aed6..f6c9488 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -520,7 +520,15 @@ common_block : INCLUDE QUOTED_STRING stmt_seperator
}
| DEFINE identifier '=' initializer_expr stmt_seperator
{
- symbol_bind(current_scope(state), $2, $4);
+ struct scope *scope = current_scope(state);
+
+ if (symbol_lookup(scope, $2) != NULL) {
+ erec_queue(error(&@2, "redfinition of symbol '%s'", $2),
+ state->msgs);
+ YYERROR;
+ }
+
+ symbol_bind(scope, $2, $4);
xfree($2);
}
| error stmt_seperator
@@ -1228,9 +1236,16 @@ symbol_expr : string
}
| '$' identifier
{
+ struct scope *scope = current_scope(state);
+
+ if (symbol_lookup(scope, $2) == NULL) {
+ erec_queue(error(&@2, "unknown identifier '%s'", $2),
+ state->msgs);
+ YYERROR;
+ }
+
$$ = symbol_expr_alloc(&@$, SYMBOL_DEFINE,
- current_scope(state),
- $2);
+ scope, $2);
xfree($2);
}
| AT identifier
diff --git a/tests/symbolic-define.1 b/tests/symbolic-define.1
new file mode 100644
index 0000000..712ef71
--- /dev/null
+++ b/tests/symbolic-define.1
@@ -0,0 +1,7 @@
+#! nft -f
+
+# error: variable use before definition
+define var2 = $var1
+define var1 = eth0
+
+filter input iif $var2
diff --git a/tests/symbolic-define.2 b/tests/symbolic-define.2
new file mode 100644
index 0000000..cd3c23c
--- /dev/null
+++ b/tests/symbolic-define.2
@@ -0,0 +1,7 @@
+#! nft -f
+
+# error: redefinition of an existing variable
+define var1 = eth0
+define var1 = eth0
+
+filter input iif $var1
diff --git a/tests/symbolic-define.3 b/tests/symbolic-define.3
new file mode 100644
index 0000000..ba224df
--- /dev/null
+++ b/tests/symbolic-define.3
@@ -0,0 +1,6 @@
+#! nft -f
+
+# error: recursive definition of a variable
+define var1 = $var1
+
+filter input iif $var1
--
1.8.5.3
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