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authorCQ Tang <cq.tang@intel.com>2013-03-18 11:02:21 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-28 12:06:03 -0700
commit84bde6521f50d67ecdb52777da3901430470bd5d (patch)
treee67312dab8c1c1a23ad211c700b7bbb3cb9c78e5
parent611f2aaf1f4de0ab50d0a3dabfb1759d13f65cf9 (diff)
x86-64: Fix the failure case in copy_user_handle_tail()
commit 66db3feb486c01349f767b98ebb10b0c3d2d021b upstream. The increment of "to" in copy_user_handle_tail() will have incremented before a failure has been noted. This causes us to skip a byte in the failure case. Only do the increment when assured there is no failure. Signed-off-by: CQ Tang <cq.tang@intel.com> Link: http://lkml.kernel.org/r/20130318150221.8439.993.stgit@phlsvslse11.ph.intel.com Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/lib/usercopy_64.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index b7c2849ffb66..554b7b528f02 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -169,10 +169,10 @@ copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
char c;
unsigned zero_len;
- for (; len; --len) {
+ for (; len; --len, to++) {
if (__get_user_nocheck(c, from++, sizeof(char)))
break;
- if (__put_user_nocheck(c, to++, sizeof(char)))
+ if (__put_user_nocheck(c, to, sizeof(char)))
break;
}