From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
broonie@kernel.org, sfr@canb.auug.org.au,
akpm@linux-foundation.org, mhocko@suse.cz,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.14 3/8] x86/uaccess: Don't leak the AC flags into __get_user() argument evaluation
Date: Mon, 9 Sep 2019 11:41:40 -0400 [thread overview]
Message-ID: <20190909154145.31263-3-sashal@kernel.org> (raw)
In-Reply-To: <20190909154145.31263-1-sashal@kernel.org>
From: Peter Zijlstra <peterz@infradead.org>
[ Upstream commit 9b8bd476e78e89c9ea26c3b435ad0201c3d7dbf5 ]
Identical to __put_user(); the __get_user() argument evalution will too
leak UBSAN crud into the __uaccess_begin() / __uaccess_end() region.
While uncommon this was observed to happen for:
drivers/xen/gntdev.c: if (__get_user(old_status, batch->status[i]))
where UBSAN added array bound checking.
This complements commit:
6ae865615fc4 ("x86/uaccess: Dont leak the AC flag into __put_user() argument evaluation")
Tested-by Sedat Dilek <sedat.dilek@gmail.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: broonie@kernel.org
Cc: sfr@canb.auug.org.au
Cc: akpm@linux-foundation.org
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: mhocko@suse.cz
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20190829082445.GM2369@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/uaccess.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 4111edb3188e2..9718303410614 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -451,8 +451,10 @@ do { \
({ \
int __gu_err; \
__inttype(*(ptr)) __gu_val; \
+ __typeof__(ptr) __gu_ptr = (ptr); \
+ __typeof__(size) __gu_size = (size); \
__uaccess_begin_nospec(); \
- __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
+ __get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err, -EFAULT); \
__uaccess_end(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
__builtin_expect(__gu_err, 0); \
--
2.20.1
next prev parent reply other threads:[~2019-09-09 22:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 15:41 [PATCH AUTOSEL 4.14 1/8] dmaengine: ti: dma-crossbar: Fix a memory leak bug Sasha Levin
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 2/8] dmaengine: ti: omap-dma: Add cleanup in omap_dma_probe() Sasha Levin
2019-09-09 15:41 ` Sasha Levin [this message]
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 4/8] x86/hyper-v: Fix overflow bug in fill_gva_list() Sasha Levin
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 5/8] configfs_register_group() shouldn't be (and isn't) called in rmdirable parts Sasha Levin
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 6/8] keys: Fix missing null pointer check in request_key_auth_describe() Sasha Levin
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 7/8] iommu/amd: Flush old domains in kdump kernel Sasha Levin
2019-09-09 15:41 ` [PATCH AUTOSEL 4.14 8/8] iommu/amd: Fix race in increase_address_space() Sasha Levin
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