Commit-ID: 0b02e20767a3b4d843d2c58cf031d9e31f60e39d Gitweb: http://git.kernel.org/tip/0b02e20767a3b4d843d2c58cf031d9e31f60e39d Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Tue, 7 Jul 2015 18:25:56 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 8 Jul 2015 11:04:45 +0200 x86/kconfig/32: Mark CONFIG_VM86 as BROKEN VM86 is entirely broken if ptrace, syscall auditing, or NOHZ_FULL is in use. The code is a big undocumented mess, it's a real PITA to test, and it looks like a big chunk of vm86_32.c is dead code. It also plays awful games with the entry asm. No one should be using it anyway. Use DOSBOX or KVM instead. Mark it BROKEN. I want to remove some (obviously incorrect) exit asm that it depends on, and I don't want to figure out how to run severely obsolete programs just to test something that no one uses for anything other than exploits anyway. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Acked-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # Backport it as far back as possible Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/Kconfig | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index aa94fd0..a7648f9b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -997,8 +997,8 @@ config X86_THERMAL_VECTOR depends on X86_MCE_INTEL config VM86 - bool "Enable VM86 support" if EXPERT - default y + bool "Enable VM86 support" if BROKEN + default n depends on X86_32 ---help--- This option is required by programs like DOSEMU to run @@ -1006,6 +1006,12 @@ config VM86 be needed by software like XFree86 to initialize some video cards via BIOS. Disabling this option saves about 6K. + Linux's VM86 support is poorly maintained, essentially never + tested by upstream kernel developers, has quite a few known + bugs, and is probably full of security holes. The only thing + that appears to use it is DOSEMU, and DOSBOX and KVM are + better options these days. Don't enable it. + config X86_16BIT bool "Enable support for 16-bit segments" if EXPERT default y -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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