fix bmcweb crash during sol communication

After establishing the obmc_console socket
communication, If client closes the connection
abruptly, async read/write operation fails with
asio.ssl.stream error. To handle the error, it calls
closeHandler call back function and cleans the session
and socket. Any ongoing async read operation should
be discarded by checking socket handle. Read/Write the
message from stream via async_read_some()/async_write
without checking socket handle, causes the crash.
Added socket handle validation before performing any
read/write operation to avoid crash.

Tested:
 - Without fix, when sol connection closes abruptly, at times
   saw the crash with below logs.
Nov 13 11:32:51 intel-obmc bmcweb[20169]: doRead error asio.ssl.stream:1
Nov 13 11:32:51 intel-obmc systemd[1]: bmcweb.service: Main process exited, code=dumped, status=11/SEGV
Nov 13 11:32:51 intel-obmc systemd[1]: bmcweb.service: Failed with result 'core-dump'.

 - With fix, verified the case and no crashes seen.
Nov 13 12:55:04 intel-obmc bmcweb[24426]: (2020-11-13 12:55:04) [ERROR "websocket.h":207] doRead error asio.ssl.stream:1
Nov 13 12:55:04 intel-obmc bmcweb[24426]: (2020-11-13 12:55:04) [ERROR "obmc_console.hpp":67] doread() - Socket closed

Signed-off-by: AppaRao Puli <apparao.puli@linux.intel.com>
Change-Id: I2afda509ca77a561651a8682e042c45ca7366642

1 files changed, 14 insertions, 0 deletions

diff --git a/include/obmc_console.hpp b/include/obmc_console.hpp
index 645ea8cdf5..17c106fbd5 100644
--- a/include/obmc_console.hpp
+++ b/include/obmc_console.hpp
@@ -36,6 +36,12 @@ inline void doWrite()
         return;
     }
 
+    if (!hostSocket)
+    {
+        BMCWEB_LOG_ERROR << "doWrite(): Socket closed.";
+        return;
+    }
+
     doingWrite = true;
     hostSocket->async_write_some(
         boost::asio::buffer(inputBuffer.data(), inputBuffer.size()),
@@ -62,6 +68,12 @@ inline void doWrite()
 
 inline void doRead()
 {
+    if (!hostSocket)
+    {
+        BMCWEB_LOG_ERROR << "doRead(): Socket closed.";
+        return;
+    }
+
     BMCWEB_LOG_DEBUG << "Reading from socket";
     hostSocket->async_read_some(
         boost::asio::buffer(outputBuffer.data(), outputBuffer.size()),
@@ -125,6 +137,8 @@ inline void requestRoutes(App& app)
         })
         .onclose([](crow::websocket::Connection& conn,
                     [[maybe_unused]] const std::string& reason) {
+            BMCWEB_LOG_INFO << "Closing websocket. Reason: " << reason;
+
             sessions.erase(&conn);
             if (sessions.empty())
             {