aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorChristophe Leroy <christophe.leroy@c-s.fr>2018-12-14 15:26:20 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-20 09:17:03 +0200
commite7ab5c78e51653c411af66308dada30f15b02413 (patch)
tree6dd0e71edb5d081df4e17cececb1e8cd29dde709
parent8167ea40725deb8617d66a3f63c08c9d924a6b04 (diff)
downloadlinux-yocto-e7ab5c78e51653c411af66308dada30f15b02413.tar.gz
linux-yocto-e7ab5c78e51653c411af66308dada30f15b02413.tar.bz2
linux-yocto-e7ab5c78e51653c411af66308dada30f15b02413.zip
lkdtm: Add tests for NULL pointer dereference
[ Upstream commit 59a12205d3c32aee4c13ca36889fdf7cfed31126 ] Introduce lkdtm tests for NULL pointer dereference: check access or exec at NULL address, since these errors tend to be reported differently from the general fault error text. For example from x86: pr_alert("BUG: unable to handle kernel %s at %px\n", address < PAGE_SIZE ? "NULL pointer dereference" : "paging request", (void *)address); Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/misc/lkdtm/core.c2
-rw-r--r--drivers/misc/lkdtm/lkdtm.h2
-rw-r--r--drivers/misc/lkdtm/perms.c18
3 files changed, 22 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index 2837dc77478e..f0f9eb30bd2b 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -152,7 +152,9 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(EXEC_VMALLOC),
CRASHTYPE(EXEC_RODATA),
CRASHTYPE(EXEC_USERSPACE),
+ CRASHTYPE(EXEC_NULL),
CRASHTYPE(ACCESS_USERSPACE),
+ CRASHTYPE(ACCESS_NULL),
CRASHTYPE(WRITE_RO),
CRASHTYPE(WRITE_RO_AFTER_INIT),
CRASHTYPE(WRITE_KERN),
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 3c6fd327e166..b69ee004a3f7 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -45,7 +45,9 @@ void lkdtm_EXEC_KMALLOC(void);
void lkdtm_EXEC_VMALLOC(void);
void lkdtm_EXEC_RODATA(void);
void lkdtm_EXEC_USERSPACE(void);
+void lkdtm_EXEC_NULL(void);
void lkdtm_ACCESS_USERSPACE(void);
+void lkdtm_ACCESS_NULL(void);
/* lkdtm_refcount.c */
void lkdtm_REFCOUNT_INC_OVERFLOW(void);
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index fa54add6375a..62f76d506f04 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -164,6 +164,11 @@ void lkdtm_EXEC_USERSPACE(void)
vm_munmap(user_addr, PAGE_SIZE);
}
+void lkdtm_EXEC_NULL(void)
+{
+ execute_location(NULL, CODE_AS_IS);
+}
+
void lkdtm_ACCESS_USERSPACE(void)
{
unsigned long user_addr, tmp = 0;
@@ -195,6 +200,19 @@ void lkdtm_ACCESS_USERSPACE(void)
vm_munmap(user_addr, PAGE_SIZE);
}
+void lkdtm_ACCESS_NULL(void)
+{
+ unsigned long tmp;
+ unsigned long *ptr = (unsigned long *)NULL;
+
+ pr_info("attempting bad read at %px\n", ptr);
+ tmp = *ptr;
+ tmp += 0xc0dec0de;
+
+ pr_info("attempting bad write at %px\n", ptr);
+ *ptr = tmp;
+}
+
void __init lkdtm_perms_init(void)
{
/* Make sure we can write to __ro_after_init values during __init */