Linux-Fsdevel Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Kees Cook <keescook@chromium.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Michael Ellerman <mpe@ellerman.id.au>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 06/11] lkdtm: disable set_fs-based tests for !CONFIG_SET_FS
Date: Tue, 18 Aug 2020 12:32:36 -0700	[thread overview]
Message-ID: <202008181228.D2DBEC6C6@keescook> (raw)
In-Reply-To: <20200817073212.830069-7-hch@lst.de>

On Mon, Aug 17, 2020 at 09:32:07AM +0200, Christoph Hellwig wrote:
> 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

Please let the test defined, but it should XFAIL with a message about
the CONFIG (see similar ifdefs in lkdtm).

>  /* 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),

Then none of these are needed.

>  #ifdef CONFIG_X86_32

Hmpf, this ifdef was missed in ae56942c1474 ("lkdtm: Make arch-specific
tests always available"). I will fix that.

> 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

(Same here, please.)

>  
>  void __init lkdtm_usercopy_init(void)
>  {
> -- 
> 2.28.0
> 

-- 
Kees Cook

  reply	other threads:[~2020-08-18 19:32 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 ` [PATCH 06/11] lkdtm: disable set_fs-based " Christoph Hellwig
2020-08-18 19:32   ` Kees Cook [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=202008181228.D2DBEC6C6@keescook \
    --to=keescook@chromium.org \
    --cc=hch@lst.de \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    --cc=viro@zeniv.linux.org.uk \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH 06/11] lkdtm: disable set_fs-based tests for '\!'CONFIG_SET_FS' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).