diff options
author | James Hogan <james.hogan@imgtec.com> | 2017-03-31 13:23:18 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-22 08:15:06 +0300 |
commit | 63916ca6f09540e0166136f0ef407c60acf21541 (patch) | |
tree | e3c91bd90dd6b3c81aaacc414eeb2585be5630bf | |
parent | f80e032430314aa07274df0b89af512a0dbaa392 (diff) | |
download | linux-63916ca6f09540e0166136f0ef407c60acf21541.tar.xz |
metag/usercopy: Fix alignment error checking
commit 2257211942bbbf6c798ab70b487d7e62f7835a1a upstream.
Fix the error checking of the alignment adjustment code in
raw_copy_from_user(), which mistakenly considers it safe to skip the
error check when aligning the source buffer on a 2 or 4 byte boundary.
If the destination buffer was unaligned it may have started to copy
using byte or word accesses, which could well be at the start of a new
(valid) source page. This would result in it appearing to have copied 1
or 2 bytes at the end of the first (invalid) page rather than none at
all.
Fixes: 373cd784d0fc ("metag: Memory handling")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | arch/metag/lib/usercopy.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index b4eb1f17069f..a6ced9691ddb 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -717,6 +717,8 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, if ((unsigned long) src & 1) { __asm_copy_from_user_1(dst, src, retn); n--; + if (retn) + goto copy_exception_bytes; } if ((unsigned long) dst & 1) { /* Worst case - byte copy */ @@ -730,6 +732,8 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, if (((unsigned long) src & 2) && n >= 2) { __asm_copy_from_user_2(dst, src, retn); n -= 2; + if (retn) + goto copy_exception_bytes; } if ((unsigned long) dst & 2) { /* Second worst case - word copy */ @@ -741,12 +745,6 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, } } - /* We only need one check after the unalignment-adjustments, - because if both adjustments were done, either both or - neither reference had an exception. */ - if (retn != 0) - goto copy_exception_bytes; - #ifdef USE_RAPF /* 64 bit copy loop */ if (!(((unsigned long) src | (unsigned long) dst) & 7)) { |