vm86: get rid of get_user_ex() use

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Just do a copyin of what we want into a local variable and
be done with that.  We are guaranteed to be on shallow stack
here...

Note that conditional expression for range passed to access_ok()
in mainline had been pointless all along - the only difference
between vm86plus_struct and vm86_struct is that the former has
one extra field in the end and when we get to copyin of that
field (conditional upon 'plus' argument), we use copy_from_user().
Moreover, all fields starting with ->int_revectored are copied
that way, so we only need that check (be it done by access_ok()
or by user_access_begin()) only on the beginning of the structure -
the fields that used to be covered by that get_user_try() block.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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This commit is contained in:

Al Viro 2020-02-15 12:09:14 -05:00

parent 4b842e4e25

commit c63aad695d

1 changed files with 24 additions and 30 deletions

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arch/x86/kernel/vm86_32.c

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