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authorDavid Windsor <dave@progbits.org>2015-12-17 00:56:36 -0500
committerKees Cook <keescook@chromium.org>2016-03-01 14:29:15 -0800
commit5fd9e48084f5566aafb759882f549f37e5940501 (patch)
tree8f44f01ff67d74fd63278db2acbb4ca9afa3095e /drivers/misc
parent920d451f9ce68e306b1f35b2029450093163d476 (diff)
lkdtm: add test for atomic_t underflow/overflow
dmesg output of running this LKDTM test with PaX: [187095.475573] lkdtm: No crash points registered, enable through debugfs [187118.020257] lkdtm: Performing direct entry WRAP_ATOMIC [187118.030045] lkdtm: attempting atomic underflow [187118.030929] PAX: refcount overflow detected in: bash:1790, uid/euid: 0/0 [187118.071667] PAX: refcount overflow occured at: lkdtm_do_action+0x19e/0x400 [lkdtm] [187118.081423] CPU: 3 PID: 1790 Comm: bash Not tainted 4.2.6-pax-refcount-split+ #2 [187118.083403] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [187118.102596] task: ffff8800da8de040 ti: ffff8800da8e4000 task.ti: ffff8800da8e4000 [187118.111321] RIP: 0010:[<ffffffffc00fc2fe>] [<ffffffffc00fc2fe>] lkdtm_do_action+0x19e/0x400 [lkdtm] ... [187118.128074] lkdtm: attempting atomic overflow [187118.128080] PAX: refcount overflow detected in: bash:1790, uid/euid: 0/0 [187118.128082] PAX: refcount overflow occured at: lkdtm_do_action+0x1b6/0x400 [lkdtm] [187118.128085] CPU: 3 PID: 1790 Comm: bash Not tainted 4.2.6-pax-refcount-split+ #2 [187118.128086] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [187118.128088] task: ffff8800da8de040 ti: ffff8800da8e4000 task.ti: ffff8800da8e4000 [187118.128092] RIP: 0010:[<ffffffffc00fc316>] [<ffffffffc00fc316>] lkdtm_do_action+0x1b6/0x400 [lkdtm] Signed-off-by: David Windsor <dave@progbits.org> [cleaned up whitespacing, keescook] Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/lkdtm.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 8e00e2e992d1..c333e813ed34 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -107,6 +107,7 @@ enum ctype {
CT_ACCESS_USERSPACE,
CT_WRITE_RO,
CT_WRITE_KERN,
+ CT_WRAP_ATOMIC
};
static char* cp_name[] = {
@@ -147,6 +148,7 @@ static char* cp_type[] = {
"ACCESS_USERSPACE",
"WRITE_RO",
"WRITE_KERN",
+ "WRAP_ATOMIC"
};
static struct jprobe lkdtm;
@@ -620,6 +622,17 @@ static void lkdtm_do_action(enum ctype which)
do_overwritten();
break;
}
+ case CT_WRAP_ATOMIC: {
+ atomic_t under = ATOMIC_INIT(INT_MIN);
+ atomic_t over = ATOMIC_INIT(INT_MAX);
+
+ pr_info("attempting atomic underflow\n");
+ atomic_dec(&under);
+ pr_info("attempting atomic overflow\n");
+ atomic_inc(&over);
+
+ return;
+ }
case CT_NONE:
default:
break;