x86/vm86: Block non-root vm86(old) if mmap_min_addr != 0

vm86 exposes an interesting attack surface against the entry
code. Since vm86 is mostly useless anyway if mmap_min_addr != 0,
just turn it off in that case.

There are some reports that vbetool can work despite setting
mmap_min_addr to zero.  This shouldn't break that use case,
as CAP_SYS_RAWIO already overrides mmap_min_addr.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Austin S Hemmelgarn <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Josh Boyer <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Garrett <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stas Sergeev <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions