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Message-Id: <20210623203936.3151093-10-keescook@chromium.org>
Date: Wed, 23 Jun 2021 13:39:36 -0700
From: Kees Cook <keescook@...omium.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Kees Cook <keescook@...omium.org>,
Guillaume Tucker <guillaume.tucker@...labora.com>,
David Laight <David.Laight@...LAB.COM>,
Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
kernelci@...ups.io, linux-kselftest@...r.kernel.org,
linux-hardening@...r.kernel.org
Subject: [PATCH 9/9] lkdtm/heap: Add init_on_alloc tests
Add SLAB and page allocator tests for init_on_alloc. Testing for
init_on_free was already happening via the poisoning tests.
Signed-off-by: Kees Cook <keescook@...omium.org>
---
drivers/misc/lkdtm/core.c | 2 +
drivers/misc/lkdtm/heap.c | 65 +++++++++++++++++++++++++
drivers/misc/lkdtm/lkdtm.h | 2 +
tools/testing/selftests/lkdtm/config | 1 +
tools/testing/selftests/lkdtm/tests.txt | 2 +
5 files changed, 72 insertions(+)
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index c185ae4719c3..9dda87c6b54a 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -127,6 +127,8 @@ static const struct crashtype crashtypes[] = {
CRASHTYPE(READ_AFTER_FREE),
CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
CRASHTYPE(READ_BUDDY_AFTER_FREE),
+ CRASHTYPE(SLAB_INIT_ON_ALLOC),
+ CRASHTYPE(BUDDY_INIT_ON_ALLOC),
CRASHTYPE(SLAB_FREE_DOUBLE),
CRASHTYPE(SLAB_FREE_CROSS),
CRASHTYPE(SLAB_FREE_PAGE),
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index a3bb0577ed8b..3d9aae5821a0 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -174,6 +174,71 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void)
kfree(val);
}
+void lkdtm_SLAB_INIT_ON_ALLOC(void)
+{
+ u8 *first;
+ u8 *val;
+
+ first = kmalloc(512, GFP_KERNEL);
+ if (!first) {
+ pr_info("Unable to allocate 512 bytes the first time.\n");
+ return;
+ }
+
+ memset(first, 0xAB, 512);
+ kfree(first);
+
+ val = kmalloc(512, GFP_KERNEL);
+ if (!val) {
+ pr_info("Unable to allocate 512 bytes the second time.\n");
+ return;
+ }
+ if (val != first) {
+ pr_warn("Reallocation missed clobbered memory.\n");
+ }
+
+ if (memchr(val, 0xAB, 512) == NULL) {
+ pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
+ } else {
+ pr_err("FAIL: Slab was not initialized\n");
+ pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
+ }
+ kfree(val);
+}
+
+void lkdtm_BUDDY_INIT_ON_ALLOC(void)
+{
+ u8 *first;
+ u8 *val;
+
+ first = (u8 *)__get_free_page(GFP_KERNEL);
+ if (!first) {
+ pr_info("Unable to allocate first free page\n");
+ return;
+ }
+
+ memset(first, 0xAB, PAGE_SIZE);
+ free_page((unsigned long)first);
+
+ val = (u8 *)__get_free_page(GFP_KERNEL);
+ if (!val) {
+ pr_info("Unable to allocate second free page\n");
+ return;
+ }
+
+ if (val != first) {
+ pr_warn("Reallocation missed clobbered memory.\n");
+ }
+
+ if (memchr(val, 0xAB, PAGE_SIZE) == NULL) {
+ pr_info("Memory appears initialized (%x, no earlier values)\n", *val);
+ } else {
+ pr_err("FAIL: Slab was not initialized\n");
+ pr_expected_config_param(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, "init_on_alloc");
+ }
+ free_page((unsigned long)val);
+}
+
void lkdtm_SLAB_FREE_DOUBLE(void)
{
int *val;
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index e491bc571808..6a30b60519f3 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -86,6 +86,8 @@ void lkdtm_WRITE_AFTER_FREE(void);
void lkdtm_READ_AFTER_FREE(void);
void lkdtm_WRITE_BUDDY_AFTER_FREE(void);
void lkdtm_READ_BUDDY_AFTER_FREE(void);
+void lkdtm_SLAB_INIT_ON_ALLOC(void);
+void lkdtm_BUDDY_INIT_ON_ALLOC(void);
void lkdtm_SLAB_FREE_DOUBLE(void);
void lkdtm_SLAB_FREE_CROSS(void);
void lkdtm_SLAB_FREE_PAGE(void);
diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config
index 849799bcfa95..013446e87f1f 100644
--- a/tools/testing/selftests/lkdtm/config
+++ b/tools/testing/selftests/lkdtm/config
@@ -5,3 +5,4 @@ CONFIG_FORTIFY_SOURCE=y
CONFIG_HARDENED_USERCOPY=y
# CONFIG_HARDENED_USERCOPY_FALLBACK is not set
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y
+CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
index 30080cc15623..846cfd508d3c 100644
--- a/tools/testing/selftests/lkdtm/tests.txt
+++ b/tools/testing/selftests/lkdtm/tests.txt
@@ -21,6 +21,8 @@ VMALLOC_LINEAR_OVERFLOW
READ_AFTER_FREE call trace:|Memory correctly poisoned
#WRITE_BUDDY_AFTER_FREE Corrupts memory on failure
READ_BUDDY_AFTER_FREE call trace:|Memory correctly poisoned
+SLAB_INIT_ON_ALLOC Memory appears initialized
+BUDDY_INIT_ON_ALLOC Memory appears initialized
SLAB_FREE_DOUBLE
SLAB_FREE_CROSS
SLAB_FREE_PAGE
--
2.30.2
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