From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Brian Delwiche <delwiche@google.com>
Date: Mon, 22 Apr 2024 16:43:29 +0000
Subject: [PATCH] Fix heap-buffer overflow in sdp_utils.cc

Fuzzer identifies a case where sdpu_compare_uuid_with_attr crashes with
an out of bounds comparison.  Although the bug claims this is due to a
comparison of a uuid with a smaller data field thana the discovery
attribute, my research suggests that this instead stems from a
comparison of a 128 bit UUID with a discovery attribute of some other,
invalid size.

Add checks for discovery attribute size.

Bug: 287184435
Test: atest bluetooth_test_gd_unit, net_test_stack_sdp
Tag: #security
Ignore-AOSP-First: Security
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:99210e2f251e2189c1eede15942c832e017404c2)
Merged-In: Ib536cbeac454efbf6af3d713c05c8e3e077e069b
Change-Id: Ib536cbeac454efbf6af3d713c05c8e3e077e069b
---
 stack/sdp/sdp_utils.cc | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/stack/sdp/sdp_utils.cc b/stack/sdp/sdp_utils.cc
index f8cde2c34..9581dc72a 100644
--- a/stack/sdp/sdp_utils.cc
+++ b/stack/sdp/sdp_utils.cc
@@ -949,8 +949,28 @@ bool sdpu_compare_uuid_arrays(uint8_t* p_uuid1, uint32_t len1, uint8_t* p_uuid2,
  ******************************************************************************/
 bool sdpu_compare_uuid_with_attr(const Uuid& uuid, tSDP_DISC_ATTR* p_attr) {
   int len = uuid.GetShortestRepresentationSize();
-  if (len == 2) return uuid.As16Bit() == p_attr->attr_value.v.u16;
-  if (len == 4) return uuid.As32Bit() == p_attr->attr_value.v.u32;
+  if (len == 2) {
+    if (SDP_DISC_ATTR_LEN(p_attr->attr_len_type) == Uuid::kNumBytes16) {
+      return uuid.As16Bit() == p_attr->attr_value.v.u16;
+    } else {
+      LOG(ERROR) << "invalid length for discovery attribute";
+      return (false);
+    }
+  }
+  if (len == 4) {
+    if (SDP_DISC_ATTR_LEN(p_attr->attr_len_type) == Uuid::kNumBytes32) {
+      return uuid.As32Bit() == p_attr->attr_value.v.u32;
+    } else {
+      LOG(ERROR) << "invalid length for discovery attribute";
+      return (false);
+    }
+  }
+
+  if (SDP_DISC_ATTR_LEN(p_attr->attr_len_type) != Uuid::kNumBytes128) {
+    LOG(ERROR) << "invalid length for discovery attribute";
+    return (false);
+  }
+
   if (memcmp(uuid.To128BitBE().data(), (void*)p_attr->attr_value.v.array,
              Uuid::kNumBytes128) == 0)
     return (true);