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Date: Tue, 3 Sep 2013 19:50:17 -0400 From: Matthew Garrett <matthew.garrett@...ula.com> To: linux-kernel@...r.kernel.org Cc: linux-efi@...r.kernel.org, keescook@...omium.org, hpa@...or.com, Matthew Garrett <matthew.garrett@...ula.com> Subject: [PATCH V3 10/11] x86: Restrict MSR access when module loading is restricted Writing to MSRs should not be allowed if module loading is restricted, since it could lead to execution of arbitrary code in kernel mode. Based on a patch by Kees Cook. Cc: Kees Cook <keescook@...omium.org> Signed-off-by: Matthew Garrett <matthew.garrett@...ula.com> --- arch/x86/kernel/msr.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index 88458fa..d08f7e3 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -103,6 +103,9 @@ static ssize_t msr_write(struct file *file, const char __user *buf, int err = 0; ssize_t bytes = 0; + if (secure_modules()) + return -EPERM; + if (count % 8) return -EINVAL; /* Invalid chunk size */ @@ -150,6 +153,10 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg) err = -EBADF; break; } + if (secure_modules()) { + err = -EPERM; + break; + } if (copy_from_user(®s, uregs, sizeof regs)) { err = -EFAULT; break; -- 1.8.3.1 -- 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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