diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-09-23 10:50:55 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-10-28 11:22:12 +0100 |
| commit | 287e013108a104e459e675432cf20087feab2b67 (patch) | |
| tree | 2eaf125b65a6bade4d86fba105305dc8c6870fa8 | |
| parent | 9c0080ef93bce34db130db6dc3bd946348e6a203 (diff) | |
| download | linux-287e013108a104e459e675432cf20087feab2b67.tar.bz2 | |
x86/vdso: Make the PER_CPU segment 32 bits
IMO users ought not to be able to use 16-bit segments without
using modify_ldt. Fortunately, it's impossible to break
espfix64 by loading the PER_CPU segment into SS because it's
PER_CPU is marked read-only and SS cannot contain an RO segment,
but marking PER_CPU as 32-bit is less fragile.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/179f490d659307873eefd09206bebd417e2ab5ad.1411494540.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/vdso/vma.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 0c7997467be0..32ca60c8157b 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -268,6 +268,7 @@ static void vsyscall_set_cpu(int cpu) .dpl = 3, /* Visible to user code */ .s = 1, /* Not a system segment */ .p = 1, /* Present */ + .d = 1, /* 32-bit */ }; write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S); |