From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit 8bfdbddd68249e0d8598777cca8249619ee51df0 ]
When you don't select CONFIG_UBSAN_TRAP, you get:
# echo ARRAY_BOUNDS > /sys/kernel/debug/provoke-crash/DIRECT [ 102.265827] ================================================================================ [ 102.278433] UBSAN: array-index-out-of-bounds in drivers/misc/lkdtm/bugs.c:342:16 [ 102.287207] index 8 is out of range for type 'char [8]' [ 102.298722] ================================================================================ [ 102.313712] lkdtm: FAIL: survived array bounds overflow! [ 102.318770] lkdtm: Unexpected! This kernel (5.16.0-rc1-s3k-dev-01884-g720dcf79314a ppc) was built with CONFIG_UBSAN_BOUNDS=y
It is not correct because when CONFIG_UBSAN_TRAP is not selected you can't expect array bounds overflow to kill the thread.
Modify the logic so that when the kernel is built with CONFIG_UBSAN_BOUNDS but without CONFIG_UBSAN_TRAP, you get a warning about CONFIG_UBSAN_TRAP not been selected instead.
This also require a fix of pr_expected_config(), otherwise the following error is encountered.
CC drivers/misc/lkdtm/bugs.o drivers/misc/lkdtm/bugs.c: In function 'lkdtm_ARRAY_BOUNDS': drivers/misc/lkdtm/bugs.c:351:2: error: 'else' without a previous 'if' 351 | else | ^~~~
Fixes: c75be56e35b2 ("lkdtm/bugs: Add ARRAY_BOUNDS to selftests") Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/363b58690e907c677252467a94fe49444c80ea76.164970438... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/lkdtm/bugs.c | 5 ++++- drivers/misc/lkdtm/lkdtm.h | 8 ++++---- 2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 4f2808b2ca3c..8cb342c562af 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -351,7 +351,10 @@ void lkdtm_ARRAY_BOUNDS(void) kfree(not_checked); kfree(checked); pr_err("FAIL: survived array bounds overflow!\n"); - pr_expected_config(CONFIG_UBSAN_BOUNDS); + if (IS_ENABLED(CONFIG_UBSAN_BOUNDS)) + pr_expected_config(CONFIG_UBSAN_TRAP); + else + pr_expected_config(CONFIG_UBSAN_BOUNDS); }
void lkdtm_CORRUPT_LIST_ADD(void) diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 305fc2ec3f25..90f87b193c1e 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -9,19 +9,19 @@ extern char *lkdtm_kernel_info;
#define pr_expected_config(kconfig) \ -{ \ +do { \ if (IS_ENABLED(kconfig)) \ pr_err("Unexpected! This %s was built with " #kconfig "=y\n", \ lkdtm_kernel_info); \ else \ pr_warn("This is probably expected, since this %s was built *without* " #kconfig "=y\n", \ lkdtm_kernel_info); \ -} +} while (0)
#ifndef MODULE int lkdtm_check_bool_cmdline(const char *param); #define pr_expected_config_param(kconfig, param) \ -{ \ +do { \ if (IS_ENABLED(kconfig)) { \ switch (lkdtm_check_bool_cmdline(param)) { \ case 0: \ @@ -52,7 +52,7 @@ int lkdtm_check_bool_cmdline(const char *param); break; \ } \ } \ -} +} while (0) #else #define pr_expected_config_param(kconfig, param) pr_expected_config(kconfig) #endif