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| author | Andy Lutomirski <luto@MIT.EDU> | 2011-06-05 19:50:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-06-05 21:30:32 +0200 |
| commit | 9fd67b4ed0714ab718f1f9bd14c344af336a6df7 (patch) | |
| tree | 7dae7e978b68479b6ee316d92b81d703cee3a894 /arch/x86/kernel/vsyscall_64.c | |
| parent | x86-64: Document some of entry_64.S (diff) | |
| download | linux-9fd67b4ed0714ab718f1f9bd14c344af336a6df7.tar.xz linux-9fd67b4ed0714ab718f1f9bd14c344af336a6df7.zip | |
x86-64: Give vvars their own page
Move vvars out of the vsyscall page into their own page and mark
it NX.
Without this patch, an attacker who can force a daemon to call
some fixed address could wait until the time contains, say,
0xCD80, and then execute the current time.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/b1460f81dc4463d66ea3f2b5ce240f58d48effec.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/vsyscall_64.c')
| -rw-r--r-- | arch/x86/kernel/vsyscall_64.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 3e682184d76c..3cf1cef75a6a 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -284,9 +284,14 @@ void __init map_vsyscall(void) { extern char __vsyscall_0; unsigned long physaddr_page0 = __pa_symbol(&__vsyscall_0); + extern char __vvar_page; + unsigned long physaddr_vvar_page = __pa_symbol(&__vvar_page); /* Note that VSYSCALL_MAPPED_PAGES must agree with the code below. */ __set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_page0, PAGE_KERNEL_VSYSCALL); + __set_fixmap(VVAR_PAGE, physaddr_vvar_page, PAGE_KERNEL_VVAR); + BUILD_BUG_ON((unsigned long)__fix_to_virt(VVAR_PAGE) != + (unsigned long)VVAR_ADDRESS); } static int __init vsyscall_init(void) |