From: Michael Farrell <micolous+gh@gmail.com>
Date: Sat, 6 Oct 2018 15:33:44 +0000 (+1000)
Subject: FIX: crash on Bionic libc if CloseProxmark is called twice. (#672)
X-Git-Tag: v3.1.0~7^2
X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/commitdiff_plain/7b2cd970ec5f158a24c5ab20db80fbfa3cb88dda

FIX: crash on Bionic libc if CloseProxmark is called twice. (#672)

In Android O and later, if an invalid pthread_t is passed to pthread_join,
it calls fatal().

https://github.com/aosp-mirror/platform_bionic/blob/ed16b344e75f422fb36fbfd91fb30de339475880/libc/bionic/pthread_internal.cpp#L116-L128

This patch addresses it by:

1. Always memset(0) on USB_communications_thread at the end of
   CloseProxmark.

2. On Bionic, only call pthread_join on USB_communications_thread if it is
   not equal to 0.
---

diff --git a/client/comms.c b/client/comms.c
index 2030f8f3..86dca3ed 100644
--- a/client/comms.c
+++ b/client/comms.c
@@ -333,7 +333,20 @@ bool OpenProxmark(void *port, bool wait_for_port, int timeout, bool flash_mode)
 
 void CloseProxmark(void) {
 	conn.run = false;
+
+#ifdef __BIONIC__
+	// In Android O and later, if an invalid pthread_t is passed to pthread_join, it calls fatal().
+	// https://github.com/aosp-mirror/platform_bionic/blob/ed16b344e75f422fb36fbfd91fb30de339475880/libc/bionic/pthread_internal.cpp#L116-L128
+	//
+	// In Bionic libc, pthread_t is an integer.
+
+	if (USB_communication_thread != 0) {
+		pthread_join(USB_communication_thread, NULL);
+	}
+#else
+	// pthread_t is a struct on other libc, treat as an opaque memory reference
 	pthread_join(USB_communication_thread, NULL);
+#endif
 
 	if (sp) {
 		uart_close(sp);
@@ -351,6 +364,7 @@ void CloseProxmark(void) {
 	// Clean up our state
 	sp = NULL;
 	serial_port_name = NULL;
+	memset(&USB_communication_thread, 0, sizeof(pthread_t));
 }