diff options
| author | James Hogan <james.hogan@imgtec.com> | 2017-03-31 11:23:18 +0100 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2017-06-17 15:55:03 +0200 |
| commit | 244522cd164c6205f1b068dfe64a6c6d2e06a8b8 (patch) | |
| tree | d99b6a3e442ac21675b14d1f042c8b163f83c05d | |
| parent | cdbd601879b8e689a0d90a160cfacf50e52fa709 (diff) | |
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: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -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 b3ebfe9c8..a26c8897b 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -830,6 +830,8 @@ 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 */ @@ -843,6 +845,8 @@ 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 */ @@ -854,12 +858,6 @@ 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)) { |