[PATCH 05/10] lkdtm: disable set_fs-based tests for !CONFIG_SET_FS
From: Christoph Hellwig <hch@lst.de>
Date: 2020-08-27 15:09:28
Also in:
linux-arch, linux-fsdevel, lkml
Subsystem:
char and misc drivers, linux kernel dump test module (lkdtm), the rest · Maintainers:
Arnd Bergmann, Greg Kroah-Hartman, Kees Cook, Linus Torvalds
Once we can't manipulate the address limit, we also can't test what happens when the manipulation is abused. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/misc/lkdtm/bugs.c | 4 ++++ drivers/misc/lkdtm/usercopy.c | 4 ++++ 2 files changed, 8 insertions(+)
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 4dfbfd51bdf774..0d5b93694a0183 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c@@ -315,11 +315,15 @@ void lkdtm_CORRUPT_LIST_DEL(void) /* Test if unbalanced set_fs(KERNEL_DS)/set_fs(USER_DS) check exists. */ void lkdtm_CORRUPT_USER_DS(void) { +#ifdef CONFIG_SET_FS pr_info("setting bad task size limit\n"); set_fs(KERNEL_DS); /* Make sure we do not keep running with a KERNEL_DS! */ force_sig(SIGKILL); +#else + pr_err("XFAIL: this requires set_fs()\n"); +#endif } /* Test that VMAP_STACK is actually allocating with a leading guard page */
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index b833367a45d053..04d10063835241 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c@@ -327,6 +327,7 @@ void lkdtm_USERCOPY_KERNEL(void) void lkdtm_USERCOPY_KERNEL_DS(void) { +#ifdef CONFIG_SET_FS char __user *user_ptr = (char __user *)(0xFUL << (sizeof(unsigned long) * 8 - 4)); mm_segment_t old_fs = get_fs();
@@ -338,6 +339,9 @@ void lkdtm_USERCOPY_KERNEL_DS(void) if (copy_to_user(user_ptr, buf, sizeof(buf)) == 0) pr_err("copy_to_user() to noncanonical address succeeded!?\n"); set_fs(old_fs); +#else + pr_err("XFAIL: this requires set_fs()\n"); +#endif } void __init lkdtm_usercopy_init(void)
--
2.28.0