Fix UAF in gatt_cl.cc
gatt_cl.cc accesses a header field after the buffer holding it may have
been freed.
Track the relevant state as a local variable instead.
Bug: 274617156
Test: atest: bluetooth, validated against fuzzer
Tag: #security
Ignore-AOSP-First: Security
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:cbaa83627b328eee8f2e26188909a5ebfb0388d5)
Merged-In: I085ecfa1a9ba098ecbfecbd3cb3e263ae13f9724
Change-Id: I085ecfa1a9ba098ecbfecbd3cb3e263ae13f9724
diff --git a/system/stack/gatt/gatt_cl.cc b/system/stack/gatt/gatt_cl.cc
index 89218e4..2698934 100644
--- a/system/stack/gatt/gatt_cl.cc
+++ b/system/stack/gatt/gatt_cl.cc
@@ -605,12 +605,17 @@
memcpy(value.value, p, value.len);
+ bool subtype_is_write_prepare = (p_clcb->op_subtype == GATT_WRITE_PREPARE);
+
if (!gatt_check_write_long_terminate(tcb, p_clcb, &value)) {
gatt_send_prepare_write(tcb, p_clcb);
return;
}
- if (p_clcb->op_subtype == GATT_WRITE_PREPARE) {
+ // We now know that we have not terminated, or else we would have returned
+ // early. We free the buffer only if the subtype is not equal to
+ // GATT_WRITE_PREPARE, so checking here is adequate to prevent UAF.
+ if (subtype_is_write_prepare) {
/* application should verify handle offset
and value are matched or not */
gatt_end_operation(p_clcb, p_clcb->status, &value);