[PATCH v7 09/10] livepatch/selftests: add data relocations test

Joe Lawrence
2023-03-06T14:12:53Z

Add a test which creates a variety of klp-data-relocations. Note that
this test case exercises late-klp-relocations for references to data.
For this, we only need to adjust pointer storage classes (and not the
target data) to affect where the relocation ends up.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
---
lib/livepatch/Makefile | 4 +-
lib/livepatch/test_klp_convert.h | 21 ++
lib/livepatch/test_klp_convert_data.c | 190 ++++++++++++++++++
lib/livepatch/test_klp_convert_mod_c.c | 36 ++++
.../selftests/livepatch/test-livepatch.sh | 95 +++++++++
5 files changed, 345 insertions(+), 1 deletion(-)
create mode 100644 lib/livepatch/test_klp_convert_data.c
create mode 100644 lib/livepatch/test_klp_convert_mod_c.c

diff --git a/lib/livepatch/Makefile b/lib/livepatch/Makefile
index 77e21317d4da..da39aaa5c8fc 100644
--- a/lib/livepatch/Makefile
+++ b/lib/livepatch/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \
test_klp_callbacks_mod.o \
test_klp_convert1.o \
test_klp_convert2.o \
+ test_klp_convert_data.o \
test_klp_convert_sections.o \
test_klp_convert_mod.o \
test_klp_livepatch.o \
@@ -19,4 +20,5 @@ obj-$(CONFIG_TEST_LIVEPATCH) += test_klp_atomic_replace.o \

test_klp_convert_mod-y := \
test_klp_convert_mod_a.o \
- test_klp_convert_mod_b.o
+ test_klp_convert_mod_b.o \
+ test_klp_convert_mod_c.o
diff --git a/lib/livepatch/test_klp_convert.h b/lib/livepatch/test_klp_convert.h
index 42befbfd63cb..08c0f4b1dc6b 100644
--- a/lib/livepatch/test_klp_convert.h
+++ b/lib/livepatch/test_klp_convert.h
@@ -12,5 +12,26 @@ extern const char *get_homonym_string(void);
extern const char *test_klp_get_driver_name(void);
extern char klp_string_a[] __asm__("klp_string.12345");
extern char klp_string_b[] __asm__("klp_string.67890");
+extern int global_small;
+// .rela.data.rel.ro, .rela.rodata supported ???:
+extern int const_global_small;
+extern int static_small;
+extern int static_const_small;
+extern int global_large[];
+// .rela.data.rel.ro, .rela.rodata supported ???:
+extern int const_global_large[];
+extern int static_large[];
+extern int static_const_large[];
+extern int local_small;
+extern int const_local_small;
+extern int static_local_small;
+extern int static_const_local_small;
+extern int local_large[4];
+extern int const_local_large[4];
+extern int static_local_large[4];
+extern int static_const_local_large[4];
+// .rela.data..ro_after_init supported ???:
+extern int static_ro_after_init;
+extern int static_read_mostly;

#endif
diff --git a/lib/livepatch/test_klp_convert_data.c b/lib/livepatch/test_klp_convert_data.c
new file mode 100644
index 000000000000..da94f7af272f
--- /dev/null
+++ b/lib/livepatch/test_klp_convert_data.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2021 Joe Lawrence <joe.lawrence@redhat.com>
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/cache.h>
+#include <linux/livepatch.h>
+#include "test_klp_convert.h"
+
+/* Small global */
+int *p_global_small = &global_small;
+
+/* Small global (const) */
+// .rela.data.rel.ro, .rela.rodata supported ???:
+int * const p_const_global_small = &const_global_small;
+
+/* Small file-static */
+static int *p_static_small = &static_small;
+
+/* Small file-static (constant) */
+static int * const p_static_const_small = &static_const_small;
+
+/* Large global */
+int *p_global_large[4] = {
+ &global_large[0], &global_large[1],
+ &global_large[2], &global_large[3],
+};
+
+/* Large global (const) */
+// .rela.data.rel.ro, .rela.rodata supported ???:
+int * const p_const_global_large[4] = {
+ &const_global_large[0], &const_global_large[1],
+ &const_global_large[2], &const_global_large[3],
+};
+
+/* Large file-static global */
+static int *p_static_large[4] = {
+ &static_large[0], &static_large[1],
+ &static_large[2], &static_large[3],
+};
+
+/* Large file-static (const) */
+static int * const p_static_const_large[4] = {
+ &static_const_large[0], &static_const_large[1],
+ &static_const_large[2], &static_const_large[3],
+};
+
+// .rela.data.rel.ro, .rela.rodata supported ???:
+// static int * __ro_after_init p_static_ro_after_init = &static_ro_after_init;
+static int * __read_mostly p_static_read_mostly = &static_read_mostly;
+
+static void print_variables(void)
+{
+ /* Small local */
+ int *p_local_small = &local_small;
+
+ /* Small local (const) */
+ int * const p_const_local_small = &const_local_small;
+
+ /* Small static-local */
+ static int *p_static_local_small = &static_local_small;
+
+ /* Small static-local (const) */
+ static int * const p_static_const_local_small = &static_const_local_small;
+
+ /* Large local */
+ int *p_local_large[4] = {
+ &local_large[0], &local_large[1],
+ &local_large[2], &local_large[3],
+ };
+
+ /* Large local (const) */
+ int * const p_const_local_large[4] = {
+ &const_local_large[0], &const_local_large[1],
+ &const_local_large[2], &const_local_large[3],
+ };
+
+ /* Large static-local local */
+ static int *p_static_local_large[4] = {
+ &static_local_large[0], &static_local_large[1],
+ &static_local_large[2], &static_local_large[3],
+ };
+
+ /* Large static-local (const) */
+ static int * const p_static_const_local_large[4] = {
+ &static_const_local_large[0], &static_const_local_large[1],
+ &static_const_local_large[2], &static_const_local_large[3],
+ };
+
+ pr_info("local_small: %x\n", *p_local_small);
+ pr_info("const_local_small: %x\n", *p_const_local_small);
+ pr_info("static_local_small: %x\n", *p_static_local_small);
+ pr_info("static_const_local_small: %x\n", *p_static_const_local_small);
+ pr_info("local_large[0..3]: %x %x %x %x\n",
+ *p_local_large[0], *p_local_large[1],
+ *p_local_large[2], *p_local_large[3]);
+ pr_info("const_local_large[0..3]: %x %x %x %x\n",
+ *p_const_local_large[0], *p_const_local_large[1],
+ *p_const_local_large[2], *p_const_local_large[3]);
+ pr_info("static_local_large[0..3]: %x %x %x %x\n",
+ *p_static_local_large[0], *p_static_local_large[1],
+ *p_static_local_large[2], *p_static_local_large[3]);
+ pr_info("static_const_local_large[0..3]: %x %x %x %x\n",
+ *p_static_const_local_large[0], *p_static_const_local_large[1],
+ *p_static_const_local_large[2], *p_static_const_local_large[3]);
+
+ pr_info("global_small: %x\n", *p_global_small);
+ // .rela.data.rel.ro, .rela.rodata supported ???:
+ pr_info("const_global_small: %x\n", *p_const_global_small);
+ pr_info("static_small: %x\n", *p_static_small);
+ pr_info("static_const_small: %x\n", *p_static_const_small);
+ pr_info("global_large[0..3]: %x %x %x %x\n",
+ *p_global_large[0], *p_global_large[1],
+ *p_global_large[2], *p_global_large[3]);
+ // .rela.data.rel.ro, .rela.rodata supported ???:
+ pr_info("const_global_large[0..3]: %x %x %x %x\n",
+ *p_const_global_large[0], *p_const_global_large[1],
+ *p_const_global_large[2], *p_const_global_large[3]);
+ pr_info("static_large[0..3]: %x %x %x %x\n",
+ *p_static_large[0], *p_static_large[1],
+ *p_static_large[2], *p_static_large[3]);
+ pr_info("static_const_large[0..3]: %x %x %x %x\n",
+ *p_static_const_large[0], *p_static_const_large[1],
+ *p_static_const_large[2], *p_static_const_large[3]);
+
+ // .rela.data..ro_after_init supported ???:
+ // pr_info("static_ro_after_init: %x\n", *p_static_ro_after_init);
+ pr_info("static_read_mostly: %x\n", *p_static_read_mostly);
+}
+
+/* provide a sysfs handle to invoke debug functions */
+static int print_debug;
+static int print_debug_set(const char *val, const struct kernel_param *kp)
+{
+ print_variables();
+
+ return 0;
+}
+static const struct kernel_param_ops print_debug_ops = {
+ .set = print_debug_set,
+ .get = param_get_int,
+};
+module_param_cb(print_debug, &print_debug_ops, &print_debug, 0200);
+MODULE_PARM_DESC(print_debug, "print klp-convert debugging info");
+
+
+static struct klp_func funcs[] = {
+ {
+ }, { }
+};
+
+static struct klp_object objs[] = {
+ {
+ /* name being NULL means vmlinux */
+ .funcs = funcs,
+ },
+ {
+ .name = "test_klp_convert_mod",
+ .funcs = funcs,
+ }, { }
+};
+
+static struct klp_patch patch = {
+ .mod = THIS_MODULE,
+ .objs = objs,
+};
+
+static int test_klp_convert_init(void)
+{
+ int ret;
+
+ ret = klp_enable_patch(&patch);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void test_klp_convert_exit(void)
+{
+}
+
+module_init(test_klp_convert_init);
+module_exit(test_klp_convert_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
+MODULE_DESCRIPTION("Livepatch test: klp-convert-data");
+MODULE_INFO(livepatch, "Y");
diff --git a/lib/livepatch/test_klp_convert_mod_c.c b/lib/livepatch/test_klp_convert_mod_c.c
new file mode 100644
index 000000000000..8f94a313e651
--- /dev/null
+++ b/lib/livepatch/test_klp_convert_mod_c.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2021 Joe Lawrence <joe.lawrence@redhat.com>
+
+#include <linux/types.h>
+
+/*
+ * test_klp_convert_data will create klp-relocations to these variables.
+ * They are named for the storage class of the variable that refers to
+ * the. This makes it easier to correlate those symbols to the
+ * relocations that refer to them in readelf output.
+ */
+__used static int global_small = 0x1111;
+// .rela.data.rel.ro, .rela.rodata supported ???:
+__used static int const_global_small = 0x2222;
+__used static int static_small = 0x3333;
+__used static int static_const_small = 0x4444;
+
+__used static int global_large[4] = { 0x1111, 0x2222, 0x3333, 0x4444 };
+// .rela.data.rel.ro, .rela.rodata supported ???:
+__used static int const_global_large[4] = { 0x5555, 0x6666, 0x7777, 0x8888 };
+__used static int static_large[4] = { 0x9999, 0xaaaa, 0xbbbb, 0xcccc };
+__used static int static_const_large[4] = { 0xdddd, 0xeeee, 0xffff, 0x0000 };
+
+__used static int local_small = 0x1111;
+__used static int const_local_small = 0x2222;
+__used static int static_local_small = 0x3333;
+__used static int static_const_local_small = 0x4444;
+
+__used static int local_large[4] = { 0x1111, 0x2222, 0x3333, 0x4444 };
+__used static int const_local_large[4] = { 0x5555, 0x6666, 0x7777, 0x8888 };
+__used static int static_local_large[4] = { 0x9999, 0xaaaa, 0xbbbb, 0xcccc };
+__used static int static_const_local_large[4] = { 0xdddd, 0xeeee, 0xffff, 0x0000 };
+
+// .rela.data..ro_after_init supported ???:
+// __used static int static_ro_after_init = 0x1111;
+__used static int static_read_mostly = 0x2222;
diff --git a/tools/testing/selftests/livepatch/test-livepatch.sh b/tools/testing/selftests/livepatch/test-livepatch.sh
index ec3b6c919b01..5bda36b65bb5 100755
--- a/tools/testing/selftests/livepatch/test-livepatch.sh
+++ b/tools/testing/selftests/livepatch/test-livepatch.sh
@@ -9,6 +9,7 @@ MOD_REPLACE=test_klp_atomic_replace
MOD_KLP_CONVERT_MOD=test_klp_convert_mod
MOD_KLP_CONVERT1=test_klp_convert1
MOD_KLP_CONVERT2=test_klp_convert2
+MOD_KLP_CONVERT_DATA=test_klp_convert_data
MOD_KLP_CONVERT_SECTIONS=test_klp_convert_sections

setup_config
@@ -340,4 +341,98 @@ livepatch: '$MOD_KLP_CONVERT_SECTIONS': unpatching complete
% rmmod $MOD_KLP_CONVERT_SECTIONS
% rmmod $MOD_KLP_CONVERT_MOD"

+
+# TEST: klp-convert data relocations
+
+start_test "klp-convert data relocations"
+
+load_mod $MOD_KLP_CONVERT_MOD
+load_lp $MOD_KLP_CONVERT_DATA
+
+echo 1 > /sys/module/$MOD_KLP_CONVERT_DATA/parameters/print_debug
+
+disable_lp $MOD_KLP_CONVERT_DATA
+unload_lp $MOD_KLP_CONVERT_DATA
+unload_mod $MOD_KLP_CONVERT_MOD
+
+check_result "% modprobe $MOD_KLP_CONVERT_MOD
+% modprobe $MOD_KLP_CONVERT_DATA
+livepatch: enabling patch '$MOD_KLP_CONVERT_DATA'
+livepatch: '$MOD_KLP_CONVERT_DATA': initializing patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': starting patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': completing patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': patching complete
+$MOD_KLP_CONVERT_DATA: local_small: 1111
+$MOD_KLP_CONVERT_DATA: const_local_small: 2222
+$MOD_KLP_CONVERT_DATA: static_local_small: 3333
+$MOD_KLP_CONVERT_DATA: static_const_local_small: 4444
+$MOD_KLP_CONVERT_DATA: local_large[0..3]: 1111 2222 3333 4444
+$MOD_KLP_CONVERT_DATA: const_local_large[0..3]: 5555 6666 7777 8888
+$MOD_KLP_CONVERT_DATA: static_local_large[0..3]: 9999 aaaa bbbb cccc
+$MOD_KLP_CONVERT_DATA: static_const_local_large[0..3]: dddd eeee ffff 0
+$MOD_KLP_CONVERT_DATA: global_small: 1111
+$MOD_KLP_CONVERT_DATA: const_global_small: 2222
+$MOD_KLP_CONVERT_DATA: static_small: 3333
+$MOD_KLP_CONVERT_DATA: static_const_small: 4444
+$MOD_KLP_CONVERT_DATA: global_large[0..3]: 1111 2222 3333 4444
+$MOD_KLP_CONVERT_DATA: const_global_large[0..3]: 5555 6666 7777 8888
+$MOD_KLP_CONVERT_DATA: static_large[0..3]: 9999 aaaa bbbb cccc
+$MOD_KLP_CONVERT_DATA: static_const_large[0..3]: dddd eeee ffff 0
+$MOD_KLP_CONVERT_DATA: static_read_mostly: 2222
+% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_DATA/enabled
+livepatch: '$MOD_KLP_CONVERT_DATA': initializing unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': starting unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': completing unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': unpatching complete
+% rmmod $MOD_KLP_CONVERT_DATA
+% rmmod $MOD_KLP_CONVERT_MOD"
+
+
+# TEST: klp-convert data relocations (late module patching)
+
+start_test "klp-convert data relocations (late module patching)"
+
+load_lp $MOD_KLP_CONVERT_DATA
+load_mod $MOD_KLP_CONVERT_MOD
+
+echo 1 > /sys/module/$MOD_KLP_CONVERT_DATA/parameters/print_debug
+
+disable_lp $MOD_KLP_CONVERT_DATA
+unload_lp $MOD_KLP_CONVERT_DATA
+unload_mod $MOD_KLP_CONVERT_MOD
+
+check_result "% modprobe $MOD_KLP_CONVERT_DATA
+livepatch: enabling patch '$MOD_KLP_CONVERT_DATA'
+livepatch: '$MOD_KLP_CONVERT_DATA': initializing patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': starting patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': completing patching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': patching complete
+% modprobe $MOD_KLP_CONVERT_MOD
+livepatch: applying patch '$MOD_KLP_CONVERT_DATA' to loading module '$MOD_KLP_CONVERT_MOD'
+$MOD_KLP_CONVERT_DATA: local_small: 1111
+$MOD_KLP_CONVERT_DATA: const_local_small: 2222
+$MOD_KLP_CONVERT_DATA: static_local_small: 3333
+$MOD_KLP_CONVERT_DATA: static_const_local_small: 4444
+$MOD_KLP_CONVERT_DATA: local_large[0..3]: 1111 2222 3333 4444
+$MOD_KLP_CONVERT_DATA: const_local_large[0..3]: 5555 6666 7777 8888
+$MOD_KLP_CONVERT_DATA: static_local_large[0..3]: 9999 aaaa bbbb cccc
+$MOD_KLP_CONVERT_DATA: static_const_local_large[0..3]: dddd eeee ffff 0
+$MOD_KLP_CONVERT_DATA: global_small: 1111
+$MOD_KLP_CONVERT_DATA: const_global_small: 2222
+$MOD_KLP_CONVERT_DATA: static_small: 3333
+$MOD_KLP_CONVERT_DATA: static_const_small: 4444
+$MOD_KLP_CONVERT_DATA: global_large[0..3]: 1111 2222 3333 4444
+$MOD_KLP_CONVERT_DATA: const_global_large[0..3]: 5555 6666 7777 8888
+$MOD_KLP_CONVERT_DATA: static_large[0..3]: 9999 aaaa bbbb cccc
+$MOD_KLP_CONVERT_DATA: static_const_large[0..3]: dddd eeee ffff 0
+$MOD_KLP_CONVERT_DATA: static_read_mostly: 2222
+% echo 0 > /sys/kernel/livepatch/$MOD_KLP_CONVERT_DATA/enabled
+livepatch: '$MOD_KLP_CONVERT_DATA': initializing unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': starting unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': completing unpatching transition
+livepatch: '$MOD_KLP_CONVERT_DATA': unpatching complete
+% rmmod $MOD_KLP_CONVERT_DATA
+% rmmod $MOD_KLP_CONVERT_MOD"
+
+
exit 0
--
2.39.2