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xtensa: fix {get,put}_user() for 64bit values

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First of all, on short copies __copy_{to,from}_user() return the amount
of bytes left uncopied, *not* -EFAULT.  get_user() and put_user() are
expected to return -EFAULT on failure.

Another problem is get_user(v32, (__u64 __user *)p); that should
fetch 64bit value and the assign it to v32, truncating it in process.
Current code, OTOH, reads 8 bytes of data and stores them at the
address of v32, stomping on the 4 bytes that follow v32 itself.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Al Viro 2019-10-09 20:21:05 +01:00 committed by Max Filippov
parent 4f5cafb5cb
commit 6595d144de
1 changed files with 11 additions and 2 deletions
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13
arch/xtensa/include/asm/uaccess.h
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@ -100,7 +100,7 @@ do { \
case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \
case 8: { \
__typeof__(*ptr) __v64 = x; \
retval = __copy_to_user(ptr, &__v64, 8); \
retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \
break; \
} \
default: __put_user_bad(); \
@ -198,7 +198,16 @@ do { \
case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\
case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\
case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\
case 8: retval = __copy_from_user(&x, ptr, 8); break; \
case 8: { \
u64 __x; \
if (unlikely(__copy_from_user(&__x, ptr, 8))) { \
retval = -EFAULT; \
(x) = 0; \
} else { \
(x) = *(__force __typeof__((ptr)))&__x; \
} \
break; \
} \
default: (x) = __get_user_bad(); \
} \
} while (0)