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From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>,
	Michael Ellerman <mpe@ellerman.id.au>,
	x86@kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 06/11] lkdtm: disable set_fs-based tests for !CONFIG_SET_FS
Date: Mon, 17 Aug 2020 09:32:07 +0200	[thread overview]
Message-ID: <20200817073212.830069-7-hch@lst.de> (raw)
In-Reply-To: <20200817073212.830069-1-hch@lst.de>

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     | 2 ++
 drivers/misc/lkdtm/core.c     | 4 ++++
 drivers/misc/lkdtm/usercopy.c | 2 ++
 3 files changed, 8 insertions(+)

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 4dfbfd51bdf774..66f1800b1cb82d 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -312,6 +312,7 @@ void lkdtm_CORRUPT_LIST_DEL(void)
 		pr_err("list_del() corruption not detected!\n");
 }
 
+#ifdef CONFIG_SET_FS
 /* Test if unbalanced set_fs(KERNEL_DS)/set_fs(USER_DS) check exists. */
 void lkdtm_CORRUPT_USER_DS(void)
 {
@@ -321,6 +322,7 @@ void lkdtm_CORRUPT_USER_DS(void)
 	/* Make sure we do not keep running with a KERNEL_DS! */
 	force_sig(SIGKILL);
 }
+#endif
 
 /* Test that VMAP_STACK is actually allocating with a leading guard page */
 void lkdtm_STACK_GUARD_PAGE_LEADING(void)
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index a5e344df916632..aae08b33a7ee2a 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -112,7 +112,9 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(CORRUPT_STACK_STRONG),
 	CRASHTYPE(CORRUPT_LIST_ADD),
 	CRASHTYPE(CORRUPT_LIST_DEL),
+#ifdef CONFIG_SET_FS
 	CRASHTYPE(CORRUPT_USER_DS),
+#endif
 	CRASHTYPE(STACK_GUARD_PAGE_LEADING),
 	CRASHTYPE(STACK_GUARD_PAGE_TRAILING),
 	CRASHTYPE(UNSET_SMEP),
@@ -172,7 +174,9 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 	CRASHTYPE(USERCOPY_STACK_BEYOND),
 	CRASHTYPE(USERCOPY_KERNEL),
+#ifdef CONFIG_SET_FS
 	CRASHTYPE(USERCOPY_KERNEL_DS),
+#endif
 	CRASHTYPE(STACKLEAK_ERASING),
 	CRASHTYPE(CFI_FORWARD_PROTO),
 #ifdef CONFIG_X86_32
diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index b833367a45d053..4b632fe79ab6bb 100644
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -325,6 +325,7 @@ void lkdtm_USERCOPY_KERNEL(void)
 	vm_munmap(user_addr, PAGE_SIZE);
 }
 
+#ifdef CONFIG_SET_FS
 void lkdtm_USERCOPY_KERNEL_DS(void)
 {
 	char __user *user_ptr =
@@ -339,6 +340,7 @@ void lkdtm_USERCOPY_KERNEL_DS(void)
 		pr_err("copy_to_user() to noncanonical address succeeded!?\n");
 	set_fs(old_fs);
 }
+#endif
 
 void __init lkdtm_usercopy_init(void)
 {
-- 
2.28.0


  parent reply	other threads:[~2020-08-17  7:33 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-17  7:32 remove the last set_fs() in common code, and remove it for x86 and powerpc Christoph Hellwig
2020-08-17  7:32 ` [PATCH 01/11] mem: remove duplicate ops for /dev/zero and /dev/null Christoph Hellwig
2020-08-18 19:33   ` Kees Cook
2020-08-17  7:32 ` [PATCH 02/11] fs: don't allow kernel reads and writes without iter ops Christoph Hellwig
2020-08-18 19:34   ` Kees Cook
2020-08-17  7:32 ` [PATCH 03/11] fs: don't allow splice read/write without explicit ops Christoph Hellwig
2020-08-18 19:39   ` Kees Cook
2020-08-18 19:54     ` Christoph Hellwig
2020-08-18 19:58       ` Kees Cook
2020-08-18 20:07         ` Christoph Hellwig
2020-08-17  7:32 ` [PATCH 04/11] uaccess: add infrastructure for kernel builds with set_fs() Christoph Hellwig
2020-08-18 19:40   ` Kees Cook
2020-08-17  7:32 ` [PATCH 05/11] test_bitmap: skip user bitmap tests for !CONFIG_SET_FS Christoph Hellwig
2020-08-17  7:50   ` Christophe Leroy
2020-08-17  7:52     ` Christoph Hellwig
2020-08-18 19:43   ` Kees Cook
2020-08-17  7:32 ` Christoph Hellwig [this message]
2020-08-18 19:32   ` [PATCH 06/11] lkdtm: disable set_fs-based " Kees Cook
2020-08-17  7:32 ` [PATCH 07/11] x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32,64}_types.h Christoph Hellwig
2020-08-18 19:27   ` Kees Cook
2020-08-17  7:32 ` [PATCH 08/11] x86: make TASK_SIZE_MAX usable from assembly code Christoph Hellwig
2020-08-18 19:44   ` Kees Cook
2020-08-18 19:55     ` Christoph Hellwig
2020-08-18 19:59       ` Kees Cook
2020-08-18 20:00         ` Christoph Hellwig
2020-08-18 20:08           ` Kees Cook
2020-08-17  7:32 ` [PATCH 09/11] x86: remove address space overrides using set_fs() Christoph Hellwig
2020-08-17  8:23   ` David Laight
2020-08-27  9:37     ` 'Christoph Hellwig'
2020-08-18 19:46   ` Kees Cook
2020-08-17  7:32 ` [PATCH 10/11] powerpc: use non-set_fs based maccess routines Christoph Hellwig
2020-08-17 15:47   ` Christophe Leroy
2020-08-17  7:32 ` [PATCH 11/11] powerpc: remove address space overrides using set_fs() Christoph Hellwig
2020-08-17  7:39 ` remove the last set_fs() in common code, and remove it for x86 and powerpc Christoph Hellwig
2020-08-18 17:46 ` Christophe Leroy
2020-08-18 18:05   ` Christoph Hellwig
2020-08-18 18:23     ` Christophe Leroy
2020-08-19  7:16       ` Christophe Leroy
2020-08-19  7:22         ` iter and normal ops on /dev/zero & co, was " Christoph Hellwig

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