Malformed input returns NULL when decoding left/right side of binop.
This causes a NULL dereference in expr_evaluate_binop; left/right must
point to a valid expression.
Fix this in the parser, else would have to sprinkle NULL checks all over
the evaluation code.
After fix, loading the bogon yields:
internal:0:0-0: Error: Malformed object (too many properties): '{}'.
internal:0:0-0: Error: could not decode binop rhs, '<<'.
internal:0:0-0: Error: Invalid mangle statement value
internal:0:0-0: Error: Parsing expr array at index 1 failed.
internal:0:0-0: Error: Parsing command array at index 3 failed.
Fixes: 0ac39384fd9e ("json: Accept more than two operands in binary expressions")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
src/parser_json.c | 14 ++++
.../nft-j-f/binop_rhs_decode_error_crash | 76 +++++++++++++++++++
2 files changed, 90 insertions(+)
create mode 100644 tests/shell/testcases/bogons/nft-j-f/binop_rhs_decode_error_crash
diff --git a/src/parser_json.c b/src/parser_json.c
index 04d762741e4a..9d5ec2275b30 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -1210,11 +1210,25 @@ static struct expr *json_parse_binop_expr(struct json_ctx *ctx,
if (json_array_size(root) > 2) {
left = json_parse_primary_expr(ctx, json_array_get(root, 0));
+ if (!left) {
+ json_error(ctx, "Failed to parse LHS of binop expression.");
+ return NULL;
+ }
right = json_parse_primary_expr(ctx, json_array_get(root, 1));
+ if (!right) {
+ json_error(ctx, "Failed to parse RHS of binop expression.");
+ expr_free(left);
+ return NULL;
+ }
left = binop_expr_alloc(int_loc, thisop, left, right);
for (i = 2; i < json_array_size(root); i++) {
jright = json_array_get(root, i);
right = json_parse_primary_expr(ctx, jright);
+ if (!right) {
+ json_error(ctx, "Failed to parse RHS of binop expression.");
+ expr_free(left);
+ return NULL;
+ }
left = binop_expr_alloc(int_loc, thisop, left, right);
}
return left;
diff --git a/tests/shell/testcases/bogons/nft-j-f/binop_rhs_decode_error_crash b/tests/shell/testcases/bogons/nft-j-f/binop_rhs_decode_error_crash
new file mode 100644
index 000000000000..c5de17111ff6
--- /dev/null
+++ b/tests/shell/testcases/bogons/nft-j-f/binop_rhs_decode_error_crash
@@ -0,0 +1,76 @@
+{
+ "nftables": [
+ {
+ "metainfo": {
+ "version": "VERSION",
+ "release_name": "RELEASE_NAME",
+ "json_schema_version": 1
+ }
+ },
+ {
+ "table": {
+ "family": "ip",
+ "name": "t",
+ "handle": 0
+ }
+ },
+ {
+ "chain": {
+ "family": "ip",
+ "table": "t",
+ "name": "c",
+ "handle": 0,
+ "type": "filter",
+ "hook": "output",
+ "prio": 0,
+ "policy": "accept"
+ }
+ },
+ {
+ "rule": {
+ "family": "ip",
+ "table": "t",
+ "chain": "c",
+ "handle": 0,
+ "expr": [
+ {
+ "match": {
+ "op": "==",
+ "left": {
+ "meta": {
+ "key": "oif"
+ }
+ },
+ "right": "lo"
+ }
+ },
+ {
+ "mangle": {
+ "key": {
+ "ct": {
+ "key": "mark"
+ }
+ },
+ "value": {
+ "<<": [
+ {
+ "|": [
+ {
+ "meta": {
+ "key": "mark"
+ }
+ },
+ 16
+ ]
+ },
+ { },
+ 8
+ ]
+ }
+ }
+ }
+ ]
+ }
+ }
+ ]
+}
--
2.48.1
