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Date: Sun, 29 May 2011 23:48:44 -0400 From: Andy Lutomirski <luto@....EDU> To: Ingo Molnar <mingo@...e.hu>, x86@...nel.org Cc: Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org, Jesper Juhl <jj@...osbits.net>, Borislav Petkov <bp@...en8.de>, Linus Torvalds <torvalds@...ux-foundation.org>, Andrew Morton <akpm@...ux-foundation.org>, Arjan van de Ven <arjan@...radead.org>, Jan Beulich <JBeulich@...ell.com>, richard -rw- weinberger <richard.weinberger@...il.com>, Mikael Pettersson <mikpe@...uu.se>, Andy Lutomirski <luto@....edu> Subject: [PATCH v2 07/10] 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@....edu> --- arch/x86/kernel/vmlinux.lds.S | 16 +++++++--------- 1 files changed, 7 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 1583238..8d6a0b7 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 -- 1.7.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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