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| author | James Hogan <james.hogan@imgtec.com> | 2017-03-31 11:23:18 +0100 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2017-04-05 14:49:36 +0100 |
| commit | 2257211942bbbf6c798ab70b487d7e62f7835a1a (patch) | |
| tree | c07090df7fa8bc3d72473de87caede42cc1c7226 /arch/metag/lib | |
| parent | ef62a2d81f73d9cddef14bc3d9097a57010d551c (diff) | |
| download | linux-2257211942bbbf6c798ab70b487d7e62f7835a1a.tar.gz linux-2257211942bbbf6c798ab70b487d7e62f7835a1a.tar.bz2 linux-2257211942bbbf6c798ab70b487d7e62f7835a1a.zip | |
metag/usercopy: Fix alignment error checking
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
Cc: stable@vger.kernel.org
Diffstat (limited to 'arch/metag/lib')
| -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)) { |