[RESEND PATCH v4 09/11] lkdtm/powerpc: Fix code patching hijack test
From: Christopher M. Riedl <hidden>
Date: 2021-05-06 04:37:11
Also in:
linux-hardening
Subsystem:
char and misc drivers, linux kernel dump test module (lkdtm), the rest · Maintainers:
Arnd Bergmann, Greg Kroah-Hartman, Kees Cook, Linus Torvalds
Code patching on powerpc with a STRICT_KERNEL_RWX uses a userspace address in a temporary mm now. Use __put_user() to avoid write failures due to KUAP when attempting a "hijack" on the patching address. Signed-off-by: Christopher M. Riedl <redacted> --- drivers/misc/lkdtm/perms.c | 9 --------- 1 file changed, 9 deletions(-)
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 55c3bec6d3b72..af9bf285fe326 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c@@ -268,16 +268,7 @@ static inline u32 lkdtm_read_patch_site(void) /* Returns True if the write succeeds */ static inline bool lkdtm_try_write(u32 data, u32 *addr) { -#ifdef CONFIG_PPC - __put_kernel_nofault(addr, &data, u32, err); - return true; - -err: - return false; -#endif -#ifdef CONFIG_X86_64 return !__put_user(data, addr); -#endif } static int lkdtm_patching_cpu(void *data)
--
2.26.1