| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 25 Jul 2014 18:13:00 -0700 From: Andy Lutomirski <luto@...capital.net> To: hpa@...or.com, x86@...nel.org, linux-kernel@...r.kernel.org Cc: Andy Lutomirski <luto@...capital.net> Subject: [PATCH 2/3] x86,vdso: Make the PER_CPU segment start out accessed The first userspace attempt to read or write the PER_CPU segment will write the accessed bit to the GDT. This is visible to userspace using the LAR instruction. Set the segment's accessed bit at boot to keep all userspace GDT access idempotent. Signed-off-by: Andy Lutomirski <luto@...capital.net> --- arch/x86/kernel/vsyscall_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 158cdff..0e2c229 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -305,7 +305,7 @@ static void vsyscall_set_cpu(int cpu) memset(&d, 0, sizeof(d)); d.limit0 = cpu | ((node & 0xf) << 12); d.limit = node >> 4; - d.type = 4; /* RO data, expand down */ + d.type = 5; /* RO data, expand down, accessed */ d.dpl = 3; /* Visible to user code */ d.s = 1; /* Non a system segment */ d.p = 1; /* Present */ -- 1.9.3 -- 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/
Powered by blists - more mailing lists