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Subject[PATCH 54/93] x86, smap: Handle csum_partial_copy_*_user()
Date
3.8.13.10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "H. Peter Anvin" <hpa@linux.intel.com>

commit 7263dda41b5a28ae6566fd126d9b06ada73dd721 upstream.

Add SMAP annotations to csum_partial_copy_to/from_user(). These
functions legitimately access user space and thus need to set the AC
flag.

TODO: add explicit checks that the side with the kernel space pointer
really points into kernel space.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-2aps0u00eer658fd5xyanan7@git.kernel.org
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
arch/x86/include/asm/checksum_32.h | 22 +++++++++++++++++-----
arch/x86/lib/csum-wrappers_64.c | 12 ++++++++++--
2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 46fc474..f50de69 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -49,9 +49,15 @@ static inline __wsum csum_partial_copy_from_user(const void __user *src,
int len, __wsum sum,
int *err_ptr)
{
+ __wsum ret;
+
might_sleep();
- return csum_partial_copy_generic((__force void *)src, dst,
- len, sum, err_ptr, NULL);
+ stac();
+ ret = csum_partial_copy_generic((__force void *)src, dst,
+ len, sum, err_ptr, NULL);
+ clac();
+
+ return ret;
}

/*
@@ -176,10 +182,16 @@ static inline __wsum csum_and_copy_to_user(const void *src,
int len, __wsum sum,
int *err_ptr)
{
+ __wsum ret;
+
might_sleep();
- if (access_ok(VERIFY_WRITE, dst, len))
- return csum_partial_copy_generic(src, (__force void *)dst,
- len, sum, NULL, err_ptr);
+ if (access_ok(VERIFY_WRITE, dst, len)) {
+ stac();
+ ret = csum_partial_copy_generic(src, (__force void *)dst,
+ len, sum, NULL, err_ptr);
+ clac();
+ return ret;
+ }

if (len)
*err_ptr = -EFAULT;
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index 25b7ae8..7609e0e 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -6,6 +6,7 @@
*/
#include <asm/checksum.h>
#include <linux/module.h>
+#include <asm/smap.h>

/**
* csum_partial_copy_from_user - Copy and checksum from user space.
@@ -52,8 +53,10 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
len -= 2;
}
}
+ stac();
isum = csum_partial_copy_generic((__force const void *)src,
dst, len, isum, errp, NULL);
+ clac();
if (unlikely(*errp))
goto out_err;

@@ -82,6 +85,8 @@ __wsum
csum_partial_copy_to_user(const void *src, void __user *dst,
int len, __wsum isum, int *errp)
{
+ __wsum ret;
+
might_sleep();

if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
@@ -105,8 +110,11 @@ csum_partial_copy_to_user(const void *src, void __user *dst,
}

*errp = 0;
- return csum_partial_copy_generic(src, (void __force *)dst,
- len, isum, NULL, errp);
+ stac();
+ ret = csum_partial_copy_generic(src, (void __force *)dst,
+ len, isum, NULL, errp);
+ clac();
+ return ret;
}
EXPORT_SYMBOL(csum_partial_copy_to_user);

--
1.8.1.2


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