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authorAndy Lutomirski <luto@MIT.EDU>2011-06-05 13:50:23 -0400
committerIngo Molnar <mingo@elte.hu>2011-06-06 09:43:14 +0200
commit5dfcea629a08b4684a019cd0cb59d0c9129a6c02 (patch)
tree0f8c7ae0db1cc4d7bf75dc7dd5612de7c741145c /arch
parentbb5fe2f78eadf5a52d8dcbf9a57728fd107af97b (diff)
downloadop-kernel-dev-5dfcea629a08b4684a019cd0cb59d0c9129a6c02.zip
op-kernel-dev-5dfcea629a08b4684a019cd0cb59d0c9129a6c02.tar.gz
x86-64: Fill unused parts of the vsyscall page with 0xcc
Jumping to 0x00 might do something depending on the following bytes. Jumping to 0xcc is a trap. So fill the unused parts of the vsyscall page with 0xcc to make it useless for exploits to jump there. 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/ed54bfcfbe50a9070d20ec1edbe0d149e22a4568.1307292171.git.luto@mit.edu Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/vmlinux.lds.S16
1 files changed, 7 insertions, 9 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 4f90082..8017471 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -166,22 +166,20 @@ SECTIONS
__vsyscall_0 = .;
. = VSYSCALL_ADDR;
- .vsyscall_0 : AT(VLOAD(.vsyscall_0)) {
+ .vsyscall : AT(VLOAD(.vsyscall)) {
*(.vsyscall_0)
- } :user
- . = ALIGN(L1_CACHE_BYTES);
- .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
+ . = ALIGN(L1_CACHE_BYTES);
*(.vsyscall_fn)
- }
- .vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) {
+ . = 1024;
*(.vsyscall_1)
- }
- .vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) {
+
+ . = 2048;
*(.vsyscall_2)
- }
+ . = 4096; /* Pad the whole page. */
+ } :user =0xcc
. = ALIGN(__vsyscall_0 + PAGE_SIZE, PAGE_SIZE);
#undef VSYSCALL_ADDR
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