Messages in this thread Patch in this message | | | From | Matthew Garrett <> | Subject | [PATCH 06/12] acpi: Limit access to custom_method if trusted_kernel is true | Date | Wed, 26 Feb 2014 15:11:07 -0500 |
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custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to modify the kernel at runtime. Prevent this if trusted_kernel is true.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> --- drivers/acpi/custom_method.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index c68e724..774bb7b 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -8,6 +8,7 @@ #include <linux/uaccess.h> #include <linux/debugfs.h> #include <linux/acpi.h> +#include <linux/security.h> #include "internal.h" @@ -29,6 +30,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, struct acpi_table_header table; acpi_status status; + if (get_trusted_kernel()) + return -EPERM; + if (!(*ppos)) { /* parse the table header to get the table length */ if (count <= sizeof(struct acpi_table_header)) -- 1.8.5.3
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