Commit e3cacae7b1bfda0d839c280494f23284a1187adf
2018-03-10T23:32:12
xkbcomp: fix crashes in the parser when geometry tokens appear In the XKB format, floats and various keywords can only be used in the xkb_geometry section. xkbcommon removed support xkb_geometry, but still parses it for backward compatibility. As part of ignoring it, the float AST node and various keywords were removed, and instead NULL was returned by their parsing actions. However, the rest of the code does not handle NULLs, and so when they appear crashes usually ensue. To fix this, restore the float AST node and the ignored keywords. None of the evaluating code expects them, so nice error are displayed. Caught with the afl fuzzer. Signed-off-by: Ran Benita <ran234@gmail.com>
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diff --git a/src/xkbcomp/ast-build.c b/src/xkbcomp/ast-build.c
index 58f97f9..9c6ccd4 100644
--- a/src/xkbcomp/ast-build.c
+++ b/src/xkbcomp/ast-build.c
@@ -106,6 +106,13 @@ ExprCreateInteger(int ival)
}
ExprDef *
+ExprCreateFloat(void)
+{
+ EXPR_CREATE(ExprFloat, expr, EXPR_VALUE, EXPR_TYPE_FLOAT);
+ return expr;
+}
+
+ExprDef *
ExprCreateBoolean(bool set)
{
EXPR_CREATE(ExprBoolean, expr, EXPR_VALUE, EXPR_TYPE_BOOLEAN);
@@ -783,6 +790,7 @@ static const char *expr_value_type_strings[_EXPR_TYPE_NUM_VALUES] = {
[EXPR_TYPE_UNKNOWN] = "unknown",
[EXPR_TYPE_BOOLEAN] = "boolean",
[EXPR_TYPE_INT] = "int",
+ [EXPR_TYPE_FLOAT] = "float",
[EXPR_TYPE_STRING] = "string",
[EXPR_TYPE_ACTION] = "action",
[EXPR_TYPE_KEYNAME] = "keyname",
diff --git a/src/xkbcomp/ast-build.h b/src/xkbcomp/ast-build.h
index b57e4cd..6c76f38 100644
--- a/src/xkbcomp/ast-build.h
+++ b/src/xkbcomp/ast-build.h
@@ -37,6 +37,9 @@ ExprDef *
ExprCreateInteger(int ival);
ExprDef *
+ExprCreateFloat(void);
+
+ExprDef *
ExprCreateBoolean(bool set);
ExprDef *
diff --git a/src/xkbcomp/ast.h b/src/xkbcomp/ast.h
index 9778884..49c5ada 100644
--- a/src/xkbcomp/ast.h
+++ b/src/xkbcomp/ast.h
@@ -95,6 +95,7 @@ enum expr_value_type {
EXPR_TYPE_UNKNOWN = 0,
EXPR_TYPE_BOOLEAN,
EXPR_TYPE_INT,
+ EXPR_TYPE_FLOAT,
EXPR_TYPE_STRING,
EXPR_TYPE_ACTION,
EXPR_TYPE_KEYNAME,
@@ -188,6 +189,12 @@ typedef struct {
typedef struct {
ExprCommon expr;
+ /* We don't support floats, but we still represnt them in the AST, in
+ * order to provide proper error messages. */
+} ExprFloat;
+
+typedef struct {
+ ExprCommon expr;
xkb_atom_t key_name;
} ExprKeyName;
diff --git a/src/xkbcomp/parser.y b/src/xkbcomp/parser.y
index ead2016..d15d24b 100644
--- a/src/xkbcomp/parser.y
+++ b/src/xkbcomp/parser.y
@@ -591,13 +591,13 @@ Element : ACTION_TOK
| INDICATOR
{ $$ = xkb_atom_intern_literal(param->ctx, "indicator"); }
| SHAPE
- { $$ = XKB_ATOM_NONE; }
+ { $$ = xkb_atom_intern_literal(param->ctx, "shape"); }
| ROW
- { $$ = XKB_ATOM_NONE; }
+ { $$ = xkb_atom_intern_literal(param->ctx, "row"); }
| SECTION
- { $$ = XKB_ATOM_NONE; }
+ { $$ = xkb_atom_intern_literal(param->ctx, "section"); }
| TEXT
- { $$ = XKB_ATOM_NONE; }
+ { $$ = xkb_atom_intern_literal(param->ctx, "text"); }
;
OptMergeMode : MergeMode { $$ = $1; }
@@ -687,7 +687,7 @@ Terminal : String
| Integer
{ $$ = ExprCreateInteger($1); }
| Float
- { $$ = NULL; }
+ { $$ = ExprCreateFloat(/* Discard $1 */); }
| KEYNAME
{ $$ = ExprCreateKeyName($1); }
;