LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Ingo Molnar <mingo@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Eric Biggers <ebiggers3@gmail.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Rik van Riel <riel@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH 03/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header in sanitize_restored_xstate()
Date: Sun, 24 Sep 2017 12:59:06 +0200
Message-ID: <20170924105913.9157-4-mingo@kernel.org> (raw)
In-Reply-To: <20170924105913.9157-1-mingo@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Tighten the checks in sanitize_restored_xstate().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: kernel-hardening@lists.openwall.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/fpu/signal.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 1ef1b228b9fd..afe54247cf27 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -214,8 +214,11 @@ sanitize_restored_xstate(struct task_struct *tsk,
 	struct xstate_header *header = &xsave->header;
 
 	if (use_xsave()) {
-		/* These bits must be zero. */
-		memset(header->reserved, 0, 48);
+		/*
+		 * Note: we don't need to zero the reserved bits in the
+		 * xstate_header here because we either didn't copy them at all,
+		 * or we checked earlier that they aren't set.
+		 */
 
 		/*
 		 * Init the state that is not present in the memory
@@ -224,7 +227,7 @@ sanitize_restored_xstate(struct task_struct *tsk,
 		if (fx_only)
 			header->xfeatures = XFEATURE_MASK_FPSSE;
 		else
-			header->xfeatures &= (xfeatures_mask & xfeatures);
+			header->xfeatures &= xfeatures;
 	}
 
 	if (use_fxsr()) {
@@ -308,7 +311,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 		/*
 		 * For 32-bit frames with fxstate, copy the user state to the
 		 * thread's fpu state, reconstruct fxstate from the fsave
-		 * header. Sanitize the copied state etc.
+		 * header. Validate and sanitize the copied state.
 		 */
 		struct fpu *fpu = &tsk->thread.fpu;
 		struct user_i387_ia32_struct env;
@@ -328,10 +331,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 			err = copy_user_to_xstate(&fpu->state.xsave, buf_fx);
 		} else {
 			err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size);
-
-			/* xcomp_bv must be 0 when using uncompacted format */
-			if (!err && fpu->state.xsave.header.xcomp_bv)
-				err = -EINVAL;
+			if (!err)
+				err = validate_xstate_header(&fpu->state.xsave.header);
 		}
 
 		if (err || __copy_from_user(&env, buf, sizeof(env))) {
-- 
2.11.0

  parent reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-24 10:59 [PATCH 00/10] x86/fpu: Split up "x86/fpu: Tighten validation of user-supplied xstate_header" Ingo Molnar
2017-09-24 10:59 ` [PATCH 01/10] x86/fpu: Introduce validate_xstate_header() Ingo Molnar
2017-09-26  8:34   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 02/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header in xstateregs_set() Ingo Molnar
2017-09-26  8:34   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` Ingo Molnar [this message]
2017-09-24 18:51   ` [PATCH 03/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header in sanitize_restored_xstate() Eric Biggers
2017-09-24 19:02     ` Ingo Molnar
2017-09-24 20:08       ` Eric Biggers
2017-09-25  6:07         ` Ingo Molnar
2017-09-25  6:14         ` Ingo Molnar
2017-09-25  7:20           ` Eric Biggers
2017-09-25  7:30             ` Ingo Molnar
2017-09-26  8:35   ` [tip:x86/fpu] x86/fpu: Use validate_xstate_header() to validate the xstate_header in __fpu__restore_sig() tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 04/10] x86/fpu: Copy the full state_header in copy_kernel_to_xstate() Ingo Molnar
2017-09-26  8:35   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 05/10] x86/fpu: Eliminate the 'xfeatures' local variable " Ingo Molnar
2017-09-26  8:35   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 06/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header " Ingo Molnar
2017-09-26  8:36   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 07/10] x86/fpu: Copy the full header in copy_user_to_xstate() Ingo Molnar
2017-09-26  8:36   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 08/10] x86/fpu: Eliminate the 'xfeatures' local variable " Ingo Molnar
2017-09-26  8:37   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 09/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header " Ingo Molnar
2017-09-26  8:37   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 10:59 ` [PATCH 10/10] x86/fpu: Use using_compacted_format() instead of open coded X86_FEATURE_XSAVES Ingo Molnar
2017-09-26  8:37   ` [tip:x86/fpu] " tip-bot for Eric Biggers
2017-09-24 18:04 ` [PATCH 00/10] x86/fpu: Split up "x86/fpu: Tighten validation of user-supplied xstate_header" Linus Torvalds
2017-09-24 19:01   ` Ingo Molnar
2017-09-26 16:28     ` [RFC GIT PULL] x86 FPU fixes and cleanups Ingo Molnar
2017-09-26 18:17       ` Linus Torvalds
2017-09-27  7:40         ` [RFC GIT PULL, v2] " Ingo Molnar

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=20170924105913.9157-4-mingo@kernel.org \
    --to=mingo@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=ebiggers3@gmail.com \
    --cc=fenghua.yu@intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@amacapital.net \
    --cc=oleg@redhat.com \
    --cc=peterz@infradead.org \
    --cc=riel@redhat.com \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --cc=yu-cheng.yu@intel.com \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git