Commit-ID: 26d35ca6c3776784f8156e1d6f80cc60d9a2a915 Gitweb: https://git.kernel.org/tip/26d35ca6c3776784f8156e1d6f80cc60d9a2a915 Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> AuthorDate: Fri, 20 Apr 2018 15:20:26 -0700 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Tue, 24 Apr 2018 09:50:54 +0200 x86/pti: Disallow global kernel text with RANDSTRUCT RANDSTRUCT derives its hardening benefits from the attacker's lack of knowledge about the layout of kernel data structures. Keep the kernel image non-global in cases where RANDSTRUCT is in use to help keep the layout a secret. Fixes: 8c06c7740 (x86/pti: Leave kernel text global for !PCID) Reported-by: Kees Cook <keescook@xxxxxxxxxx> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Nadav Amit <namit@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Link: https://lkml.kernel.org/r/20180420222026.D0B4AAC9@xxxxxxxxxxxxxxxxxx --- arch/x86/mm/pti.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index ae3eb4f5d53b..4d418e705878 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -421,6 +421,16 @@ static inline bool pti_kernel_image_global_ok(void) if (boot_cpu_has(X86_FEATURE_K8)) return false; + /* + * RANDSTRUCT derives its hardening benefits from the + * attacker's lack of knowledge about the layout of kernel + * data structures. Keep the kernel image non-global in + * cases where RANDSTRUCT is in use to help keep the layout a + * secret. + */ + if (IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT)) + return false; + return true; } -- 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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