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From: tip-bot for Stephen Smalley <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: mingo@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	hpa@zytor.com, peterz@infradead.org, efault@gmx.de,
	stable@vger.kernel.org, keescook@chromium.org, sds@tycho.nsa.gov
Subject: [tip:x86/urgent] x86/mm: Set NX on gap between __ex_table and rodata
Date: Fri, 2 Oct 2015 00:45:35 -0700	[thread overview]
Message-ID: <tip-ab76f7b4ab2397ffdd2f1eb07c55697d19991d10@git.kernel.org> (raw)
In-Reply-To: <1443704662-3138-1-git-send-email-sds@tycho.nsa.gov>

Commit-ID:  ab76f7b4ab2397ffdd2f1eb07c55697d19991d10
Gitweb:     http://git.kernel.org/tip/ab76f7b4ab2397ffdd2f1eb07c55697d19991d10
Author:     Stephen Smalley <sds@tycho.nsa.gov>
AuthorDate: Thu, 1 Oct 2015 09:04:22 -0400
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 2 Oct 2015 09:21:06 +0200

x86/mm: Set NX on gap between __ex_table and rodata

Unused space between the end of __ex_table and the start of
rodata can be left W+x in the kernel page tables.  Extend the
setting of the NX bit to cover this gap by starting from
text_end rather than rodata_start.

  Before:
  ---[ High Kernel Mapping ]---
  0xffffffff80000000-0xffffffff81000000          16M                               pmd
  0xffffffff81000000-0xffffffff81600000           6M     ro         PSE     GLB x  pmd
  0xffffffff81600000-0xffffffff81754000        1360K     ro                 GLB x  pte
  0xffffffff81754000-0xffffffff81800000         688K     RW                 GLB x  pte
  0xffffffff81800000-0xffffffff81a00000           2M     ro         PSE     GLB NX pmd
  0xffffffff81a00000-0xffffffff81b3b000        1260K     ro                 GLB NX pte
  0xffffffff81b3b000-0xffffffff82000000        4884K     RW                 GLB NX pte
  0xffffffff82000000-0xffffffff82200000           2M     RW         PSE     GLB NX pmd
  0xffffffff82200000-0xffffffffa0000000         478M                               pmd

  After:
  ---[ High Kernel Mapping ]---
  0xffffffff80000000-0xffffffff81000000          16M                               pmd
  0xffffffff81000000-0xffffffff81600000           6M     ro         PSE     GLB x  pmd
  0xffffffff81600000-0xffffffff81754000        1360K     ro                 GLB x  pte
  0xffffffff81754000-0xffffffff81800000         688K     RW                 GLB NX pte
  0xffffffff81800000-0xffffffff81a00000           2M     ro         PSE     GLB NX pmd
  0xffffffff81a00000-0xffffffff81b3b000        1260K     ro                 GLB NX pte
  0xffffffff81b3b000-0xffffffff82000000        4884K     RW                 GLB NX pte
  0xffffffff82000000-0xffffffff82200000           2M     RW         PSE     GLB NX pmd
  0xffffffff82200000-0xffffffffa0000000         478M                               pmd

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1443704662-3138-1-git-send-email-sds@tycho.nsa.gov
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/mm/init_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 30564e2..df48430 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1132,7 +1132,7 @@ void mark_rodata_ro(void)
 	 * has been zapped already via cleanup_highmem().
 	 */
 	all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
-	set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
+	set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);
 
 	rodata_test();
 

      parent reply	other threads:[~2015-10-02  7:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-01 13:04 [PATCH] " Stephen Smalley
2015-10-01 16:35 ` Kees Cook
2015-10-02  7:45 ` tip-bot for Stephen Smalley [this message]

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