linux-kernel - [PATCH 1/1] kgdb: don't needlessly skip PAGE

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Date:	Thu, 29 Apr 2010 21:56:37 -0500
From:	Jason Wessel <jason.wessel@...driver.com>
To:	torvalds@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, kgdb-bugreport@...ts.sourceforge.net,
	stable@...nel.org, Wufei <fei.wu@...driver.com>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Kumar Gala <galak@...nel.crashing.org>,
	Jason Wessel <jason.wessel@...driver.com>
Subject: [PATCH 1/1] kgdb: don't needlessly skip PAGE_USER test for Fsl booke

From: Wufei <fei.wu@...driver.com>

The bypassing of this test is a leftover from 2.4 vintage
kernels, and is no longer appropriate, or even used by KGDB.
Currently KGDB uses probe_kernel_write() for all access to
memory via the KGDB core, so it can simply be deleted.

This fixes CVE-2010-1446.

CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
CC: Paul Mackerras <paulus@...ba.org>
CC: Kumar Gala <galak@...nel.crashing.org>
Signed-off-by: Wufei <fei.wu@...driver.com>
Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
---
 arch/powerpc/mm/fsl_booke_mmu.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index c539472..1ce9dd5 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -155,15 +155,10 @@ static void settlbcam(int index, unsigned long virt, phys_addr_t phys,
 	if (cur_cpu_spec->cpu_features & MMU_FTR_BIG_PHYS)
 		TLBCAM[index].MAS7 = (u64)phys >> 32;
 
-#ifndef CONFIG_KGDB /* want user access for breakpoints */
 	if (flags & _PAGE_USER) {
 	   TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
 	   TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
 	}
-#else
-	TLBCAM[index].MAS3 |= MAS3_UX | MAS3_UR;
-	TLBCAM[index].MAS3 |= ((flags & _PAGE_RW) ? MAS3_UW : 0);
-#endif
 
 	tlbcam_addrs[index].start = virt;
 	tlbcam_addrs[index].limit = virt + size - 1;
-- 
1.6.3.3

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