From: Matthew Garrett <mjg@redhat.com> To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, Matthew Garrett <mjg@redhat.com> Subject: [PATCH 06/11] Restrict /dev/mem and /dev/kmem in secure boot setups Date: Tue, 4 Sep 2012 11:55:12 -0400 [thread overview] Message-ID: <1346774117-2277-7-git-send-email-mjg@redhat.com> (raw) In-Reply-To: <1346774117-2277-1-git-send-email-mjg@redhat.com> Allowing users to write to address space makes it possible for the kernel to be subverted. Restrict this when we need to protect the kernel. Signed-off-by: Matthew Garrett <mjg@redhat.com> --- drivers/char/mem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 8f5f872..c1de8e1 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -158,6 +158,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, unsigned long copied; void *ptr; + if (!capable(CAP_SECURE_FIRMWARE)) + return -EPERM; + if (!valid_phys_addr_range(p, count)) return -EFAULT; @@ -530,6 +533,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf, char * kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */ int err = 0; + if (!capable(CAP_SECURE_FIRMWARE)) + return -EPERM; + if (p < (unsigned long) high_memory) { unsigned long to_write = min_t(unsigned long, count, (unsigned long)high_memory - p); -- 1.7.11.4
next prev parent reply other threads:[~2012-09-04 15:56 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-09-04 15:55 [RFC] First attempt at kernel secure boot support Matthew Garrett 2012-09-04 15:55 ` [PATCH 01/11] Secure boot: Add new capability Matthew Garrett 2012-09-04 15:55 ` [PATCH 02/11] PCI: Lock down BAR access in secure boot environments Matthew Garrett 2012-10-01 21:00 ` Pavel Machek 2012-09-04 15:55 ` [PATCH 03/11] x86: Lock down IO port " Matthew Garrett 2012-09-04 16:16 ` Alan Cox 2012-09-04 16:16 ` Matthew Garrett 2012-09-04 15:55 ` [PATCH 04/11] ACPI: Limit access to custom_method Matthew Garrett 2012-09-04 15:55 ` [PATCH 05/11] asus-wmi: Restrict debugfs interface Matthew Garrett 2012-09-04 16:12 ` Alan Cox 2012-09-04 16:13 ` Matthew Garrett 2012-09-04 15:55 ` Matthew Garrett [this message] 2012-09-04 15:55 ` [PATCH 07/11] kexec: Disable in a secure boot environment Matthew Garrett 2012-09-04 20:13 ` Eric W. Biederman 2012-09-04 20:22 ` Matthew Garrett 2012-09-04 21:13 ` Eric W. Biederman 2012-09-04 21:27 ` Matthew Garrett 2012-09-04 22:12 ` Eric W. Biederman 2012-09-04 23:25 ` Matthew Garrett 2012-09-05 4:33 ` Eric W. Biederman 2012-09-05 5:16 ` Matthew Garrett 2012-09-05 7:00 ` Eric W. Biederman 2012-09-05 7:03 ` Matthew Garrett 2012-09-04 21:39 ` Alan Cox 2012-09-04 21:40 ` Matthew Garrett 2012-09-05 15:43 ` Roland Eggner 2012-09-05 15:46 ` Matthew Garrett 2012-09-05 21:13 ` Mimi Zohar 2012-09-05 21:41 ` Matthew Garrett 2012-09-05 21:49 ` Eric Paris 2012-09-04 15:55 ` [PATCH 08/11] Secure boot: Add a dummy kernel parameter that will switch on Secure Boot mode Matthew Garrett 2012-09-04 15:55 ` [PATCH 09/11] efi: Enable secure boot lockdown automatically when enabled in firmware Matthew Garrett 2012-09-04 15:55 ` [PATCH 10/11] acpi: Ignore acpi_rsdp kernel parameter in a secure boot environment Matthew Garrett 2012-09-04 16:30 ` Shuah Khan 2012-09-04 16:38 ` Matthew Garrett 2012-09-04 16:44 ` Shuah Khan 2012-09-04 20:37 ` Alan Cox 2012-09-04 20:37 ` Matthew Garrett 2012-09-04 20:50 ` Josh Boyer 2012-09-04 15:55 ` [PATCH 11/11] SELinux: define mapping for new Secure Boot capability Matthew Garrett 2012-09-04 16:08 ` [RFC] First attempt at kernel secure boot support Alan Cox 2012-09-04 16:12 ` Matthew Garrett 2012-10-01 21:07 ` Pavel Machek
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