From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Chienyuan <chienyuanhuang@google.com>
Date: Tue, 12 Feb 2019 16:01:00 +0800
Subject: [PATCH] Fix OOB in bnep_is_packet_allowed

Bug: 112050983
Test: PoC
Change-Id: I5d331f46cdba86c8e61de206a2ede1d2b348d7e4
(cherry picked from commit 230f252b8a1a1073ec1a4081545b2ff62393d16d)
CRs-Fixed: 3155069
---
 stack/bnep/bnep_api.cc   | 13 +++++++++++--
 stack/bnep/bnep_int.h    |  4 ++--
 stack/bnep/bnep_utils.cc | 12 +++++++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/stack/bnep/bnep_api.cc b/stack/bnep/bnep_api.cc
index 0e7b69208..aaa97603f 100644
--- a/stack/bnep/bnep_api.cc
+++ b/stack/bnep/bnep_api.cc
@@ -349,7 +349,7 @@ tBNEP_RESULT BNEP_WriteBuf(uint16_t handle, const RawAddress& p_dest_addr,
   /* Check if the packet should be filtered out */
   p_data = (uint8_t*)(p_buf + 1) + p_buf->offset;
   if (bnep_is_packet_allowed(p_bcb, p_dest_addr, protocol, fw_ext_present,
-                             p_data) != BNEP_SUCCESS) {
+                             p_data, p_buf->len) != BNEP_SUCCESS) {
     /*
     ** If packet is filtered and ext headers are present
     ** drop the data and forward the ext headers
@@ -361,6 +361,11 @@ tBNEP_RESULT BNEP_WriteBuf(uint16_t handle, const RawAddress& p_dest_addr,
       org_len = p_buf->len;
       new_len = 0;
       do {
+        if ((new_len + 2) > org_len) {
+          osi_free(p_buf);
+          return BNEP_IGNORE_CMD;
+        }
+
         ext = *p_data++;
         length = *p_data++;
         p_data += length;
@@ -448,7 +453,7 @@ tBNEP_RESULT BNEP_Write(uint16_t handle, const RawAddress& p_dest_addr,
 
   /* Check if the packet should be filtered out */
   if (bnep_is_packet_allowed(p_bcb, p_dest_addr, protocol, fw_ext_present,
-                             p_data) != BNEP_SUCCESS) {
+                             p_data, len) != BNEP_SUCCESS) {
     /*
     ** If packet is filtered and ext headers are present
     ** drop the data and forward the ext headers
@@ -461,6 +466,10 @@ tBNEP_RESULT BNEP_Write(uint16_t handle, const RawAddress& p_dest_addr,
       new_len = 0;
       p = p_data;
       do {
+        if ((new_len + 2) > org_len) {
+          return BNEP_IGNORE_CMD;
+        }
+
         ext = *p_data++;
         length = *p_data++;
         p_data += length;
diff --git a/stack/bnep/bnep_int.h b/stack/bnep/bnep_int.h
index 2587147cc..5bba15da8 100644
--- a/stack/bnep/bnep_int.h
+++ b/stack/bnep/bnep_int.h
@@ -229,7 +229,7 @@ extern void bnep_sec_check_complete(const RawAddress* bd_addr,
 extern tBNEP_RESULT bnep_is_packet_allowed(tBNEP_CONN* p_bcb,
                                            const RawAddress& p_dest_addr,
                                            uint16_t protocol,
-                                           bool fw_ext_present,
-                                           uint8_t* p_data);
+                                           bool fw_ext_present, uint8_t* p_data,
+                                           uint16_t org_len);
 
 #endif
diff --git a/stack/bnep/bnep_utils.cc b/stack/bnep/bnep_utils.cc
index 48fd5d12b..f8c0203a9 100644
--- a/stack/bnep/bnep_utils.cc
+++ b/stack/bnep/bnep_utils.cc
@@ -1259,23 +1259,33 @@ void bnep_sec_check_complete(UNUSED_ATTR const RawAddress* bd_addr,
 tBNEP_RESULT bnep_is_packet_allowed(tBNEP_CONN* p_bcb,
                                     const RawAddress& p_dest_addr,
                                     uint16_t protocol, bool fw_ext_present,
-                                    uint8_t* p_data) {
+                                    uint8_t* p_data, uint16_t org_len) {
   if (p_bcb->rcvd_num_filters) {
     uint16_t i, proto;
 
     /* Findout the actual protocol to check for the filtering */
     proto = protocol;
     if (proto == BNEP_802_1_P_PROTOCOL) {
+      uint16_t new_len = 0;
       if (fw_ext_present) {
         uint8_t len, ext;
         /* parse the extension headers and findout actual protocol */
         do {
+          if ((new_len + 2) > org_len) {
+            return BNEP_IGNORE_CMD;
+          }
+
           ext = *p_data++;
           len = *p_data++;
           p_data += len;
 
+          new_len += (len + 2);
+
         } while (ext & 0x80);
       }
+      if ((new_len + 4) > org_len) {
+        return BNEP_IGNORE_CMD;
+      }
       p_data += 2;
       BE_STREAM_TO_UINT16(proto, p_data);
     }