commit 541d3cdc0771b8de00ef4964bbfd50384b4b8c75
author Matthew Maurer <mmaurer@google.com> Tue Jun 18 12:17:28 2019 -0700
committer Matthew Maurer <mmaurer@google.com> Tue Jul 16 23:02:30 2019 +0000
tree dfe0c14a026cb60ee65ff2c2b5ef390f5632291f
parent c0bf7ba7dd7505bf3f89a4f9402f85c3d4e61da0

[app-mgmt-test] Use gauranteed invalid address

While it is unlikely, with ASLR or an unusual ELF the top page
(previously used as an invalid user address) could be occupied.

We currently forbid mapping pages below 0x8000, so this is more clearly
unmapped, but is neither NULL nor in the kernel range.

Bug: 80146040
Change-Id: I4b915b692fe5f20f4033009cbd7fade8f3b84395

app-mgmt-test/syscalls-test/main/main.c

diff --git a/app-mgmt-test/syscalls-test/main/main.c b/app-mgmt-test/syscalls-test/main/main.c
index e7d91dc..b2ac0ad 100644
--- a/app-mgmt-test/syscalls-test/main/main.c
+++ b/app-mgmt-test/syscalls-test/main/main.c
@@ -30,7 +30,7 @@
 #define PORT_BASE "com.android.appmgmt-unittest.syscalls"
 
 #define KERNEL_ADDRESS KERNEL_ASPACE_BASE
-#define INVALID_USER_ADDRESS (USER_ASPACE_BASE + USER_ASPACE_SIZE - 0x1000)
+#define INVALID_USER_ADDRESS (0x1000)
 
 #define TEST_DATA_BYTE 0x5a
 #define PAGE_SIZE 4096