From 57d5f3ee1318678332652342e18072230bfaea45 Mon Sep 17 00:00:00 2001
From: Henri Sivonen <hsivonen@hsivonen.fi>
Date: Tue, 21 Aug 2018 14:20:48 +0000
Subject: [PATCH] Bug 1484984 - Avoid writing past the logical length of a
 string in networking code. r=valentin

MozReview-Commit-ID: IIffoxnF6KS

Differential Revision: https://phabricator.services.mozilla.com/D3884

--HG--
extra : moz-landing-system : lando
---
 netwerk/base/Dashboard.cpp                 | 2 +-
 netwerk/base/nsNetAddr.cpp                 | 4 ++--
 netwerk/base/nsSocketTransport2.cpp        | 2 +-
 netwerk/protocol/http/Http2Compression.cpp | 2 +-
 netwerk/protocol/http/HttpBaseChannel.cpp  | 4 ++--
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/netwerk/base/Dashboard.cpp b/netwerk/base/Dashboard.cpp
index 4868b52e701d..5f0c77d286d5 100644
--- a/netwerk/base/Dashboard.cpp
+++ b/netwerk/base/Dashboard.cpp
@@ -886,7 +886,7 @@ HttpConnInfo::SetHTTP2ProtocolVersion(SpdyVersion pv)
 NS_IMETHODIMP
 Dashboard::GetLogPath(nsACString &aLogPath)
 {
-    aLogPath.SetCapacity(2048);
+    aLogPath.SetLength(2048);
     uint32_t len = LogModule::GetLogFile(aLogPath.BeginWriting(), 2048);
     aLogPath.SetLength(len);
     return NS_OK;
diff --git a/netwerk/base/nsNetAddr.cpp b/netwerk/base/nsNetAddr.cpp
index 19eb4bd597bc..01c496ec94de 100644
--- a/netwerk/base/nsNetAddr.cpp
+++ b/netwerk/base/nsNetAddr.cpp
@@ -45,12 +45,12 @@ NS_IMETHODIMP nsNetAddr::GetAddress(nsACString & aAddress)
   switch(mAddr.raw.family) {
   /* PR_NetAddrToString can handle INET and INET6, but not LOCAL. */
   case AF_INET:
-    aAddress.SetCapacity(kIPv4CStrBufSize);
+    aAddress.SetLength(kIPv4CStrBufSize);
     NetAddrToString(&mAddr, aAddress.BeginWriting(), kIPv4CStrBufSize);
     aAddress.SetLength(strlen(aAddress.BeginReading()));
     break;
   case AF_INET6:
-    aAddress.SetCapacity(kIPv6CStrBufSize);
+    aAddress.SetLength(kIPv6CStrBufSize);
     NetAddrToString(&mAddr, aAddress.BeginWriting(), kIPv6CStrBufSize);
     aAddress.SetLength(strlen(aAddress.BeginReading()));
     break;
diff --git a/netwerk/base/nsSocketTransport2.cpp b/netwerk/base/nsSocketTransport2.cpp
index e606e571007f..df155e4c5f96 100644
--- a/netwerk/base/nsSocketTransport2.cpp
+++ b/netwerk/base/nsSocketTransport2.cpp
@@ -1344,7 +1344,7 @@ nsSocketTransport::InitiateSocket()
         IsIPAddrLocal(&mNetAddr)) {
         if (SOCKET_LOG_ENABLED()) {
             nsAutoCString netAddrCString;
-            netAddrCString.SetCapacity(kIPv6CStrBufSize);
+            netAddrCString.SetLength(kIPv6CStrBufSize);
             if (!NetAddrToString(&mNetAddr,
                                  netAddrCString.BeginWriting(),
                                  kIPv6CStrBufSize))
diff --git a/netwerk/protocol/http/Http2Compression.cpp b/netwerk/protocol/http/Http2Compression.cpp
index 4ee353eec693..08e6934e53c4 100644
--- a/netwerk/protocol/http/Http2Compression.cpp
+++ b/netwerk/protocol/http/Http2Compression.cpp
@@ -1092,8 +1092,8 @@ Http2Compressor::EncodeHeaderBlock(const nsCString &nvInput,
 {
   mSetInitialMaxBufferSizeAllowed = false;
   mOutput = &output;
-  output.SetCapacity(1024);
   output.Truncate();
+  output.SetCapacity(1024);
   mParsedContentLength = -1;
 
   // first thing's first - context size updates (if necessary)
diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
index 31221da0d64e..099d10398a19 100644
--- a/netwerk/protocol/http/HttpBaseChannel.cpp
+++ b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -2591,7 +2591,7 @@ HttpBaseChannel::GetLocalAddress(nsACString& addr)
   if (mSelfAddr.raw.family == PR_AF_UNSPEC)
     return NS_ERROR_NOT_AVAILABLE;
 
-  addr.SetCapacity(kIPv6CStrBufSize);
+  addr.SetLength(kIPv6CStrBufSize);
   NetAddrToString(&mSelfAddr, addr.BeginWriting(), kIPv6CStrBufSize);
   addr.SetLength(strlen(addr.BeginReading()));
 
@@ -2700,7 +2700,7 @@ HttpBaseChannel::GetRemoteAddress(nsACString& addr)
   if (mPeerAddr.raw.family == PR_AF_UNSPEC)
     return NS_ERROR_NOT_AVAILABLE;
 
-  addr.SetCapacity(kIPv6CStrBufSize);
+  addr.SetLength(kIPv6CStrBufSize);
   NetAddrToString(&mPeerAddr, addr.BeginWriting(), kIPv6CStrBufSize);
   addr.SetLength(strlen(addr.BeginReading()));