adb: fix host-side serial number parsing for IPv6.

When the adb client sends a command to the adb server targeting a
particular device serial, it looks something like this:
  host-serial:<serial>:<command>

But if <serial> happens to be an IPv6 address (e.g. when `adb connect`
targets IPv6), the current parsing code doesn't handle the additional
colons properly. This CL fixes the host-serial parsing to handle this
case.

This only affects commands that explicitly name a device serial, e.g.:
  adb -s <IPv6> shell
  adb -s <IPv6> forward <port> <port>
Implicitly using a single attached device was unaffected by this bug.

Bug: http://b/30891386
Test: `adb -s [fe80::ba27:ebff:feb1:934%eth2]:5555 shell` works now,
      and new unittests pass.
Change-Id: Iffe784e61432ae94eb96ed3c8477900a3e807329

2 files changed, 27 insertions, 5 deletions

diff --git a/adb/socket_test.cpp b/adb/socket_test.cpp
index 2bb01a382..5e79b5e2e 100644
--- a/adb/socket_test.cpp
+++ b/adb/socket_test.cpp
@@ -307,6 +307,17 @@ TEST(socket_test, test_skip_host_serial) {
         // Don't register a port unless it's all numbers and ends with ':'.
         VerifySkipHostSerial(protocol + "foo:123", ":123");
         VerifySkipHostSerial(protocol + "foo:123bar:baz", ":123bar:baz");
+
+        VerifySkipHostSerial(protocol + "100.100.100.100:5555:foo", ":foo");
+        VerifySkipHostSerial(protocol + "[0123:4567:89ab:CDEF:0:9:a:f]:5555:foo", ":foo");
+        VerifySkipHostSerial(protocol + "[::1]:5555:foo", ":foo");
+
+        // If we can't find both [] then treat it as a normal serial with [ in it.
+        VerifySkipHostSerial(protocol + "[0123:foo", ":foo");
+
+        // Don't be fooled by random IPv6 addresses in the command string.
+        VerifySkipHostSerial(protocol + "foo:ping [0123:4567:89ab:CDEF:0:9:a:f]:5555",
+                             ":ping [0123:4567:89ab:CDEF:0:9:a:f]:5555");
     }
 }
 
diff --git a/adb/sockets.cpp b/adb/sockets.cpp
index abba7452b..41372e5cc 100644
--- a/adb/sockets.cpp
+++ b/adb/sockets.cpp
@@ -622,21 +622,32 @@ char* skip_host_serial(char* service) {
         service += 4;
     }
 
-    char* first_colon = strchr(service, ':');
-    if (!first_colon) {
+    // Check for an IPv6 address. `adb connect` creates the serial number from the canonical
+    // network address so it will always have the [] delimiters.
+    if (service[0] == '[') {
+        char* ipv6_end = strchr(service, ']');
+        if (ipv6_end != nullptr) {
+            service = ipv6_end;
+        }
+    }
+
+    // The next colon we find must either begin the port field or the command field.
+    char* colon_ptr = strchr(service, ':');
+    if (!colon_ptr) {
         // No colon in service string.
         return nullptr;
     }
 
-    char* serial_end = first_colon;
+    // If the next field is only decimal digits and ends with another colon, it's a port.
+    char* serial_end = colon_ptr;
     if (isdigit(serial_end[1])) {
         serial_end++;
         while (*serial_end && isdigit(*serial_end)) {
             serial_end++;
         }
         if (*serial_end != ':') {
-            // Something other than numbers was found, reset the end.
-            serial_end = first_colon;
+            // Something other than "<port>:" was found, this must be the command field instead.
+            serial_end = colon_ptr;
         }
     }
     return serial_end;