From 526b4af47f44148c9d665e57723ed9f86634c6e3 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Thu, 26 May 2011 12:26:24 +0200 Subject: ACPI: Split out custom_method functionality into an own driver With /sys/kernel/debug/acpi/custom_method root can write to arbitrary memory and increase his priveleges, even if these are restricted. -> Make this an own debug .config option and warn about the security issue in the config description. -> Still keep acpi/debugfs.c which now only creates an empty /sys/kernel/debug/acpi directory. There might be other users of it later. Signed-off-by: Thomas Renninger Acked-by: Rafael J. Wysocki Acked-by: rui.zhang@intel.com Signed-off-by: Len Brown --- drivers/acpi/debugfs.c | 80 +------------------------------------------------- 1 file changed, 1 insertion(+), 79 deletions(-) (limited to 'drivers/acpi/debugfs.c') diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c index e7abc6e3bba0..182a9fc36355 100644 --- a/drivers/acpi/debugfs.c +++ b/drivers/acpi/debugfs.c @@ -3,9 +3,6 @@ */ #include -#include -#include -#include #include #include @@ -13,84 +10,9 @@ ACPI_MODULE_NAME("debugfs"); struct dentry *acpi_debugfs_dir; -static struct dentry *cm_dentry; - -/* /sys/kernel/debug/acpi/custom_method */ - -static ssize_t cm_write(struct file *file, const char __user * user_buf, - size_t count, loff_t *ppos) -{ - static char *buf; - static u32 max_size; - static u32 uncopied_bytes; - - struct acpi_table_header table; - acpi_status status; - - if (!(*ppos)) { - /* parse the table header to get the table length */ - if (count <= sizeof(struct acpi_table_header)) - return -EINVAL; - if (copy_from_user(&table, user_buf, - sizeof(struct acpi_table_header))) - return -EFAULT; - uncopied_bytes = max_size = table.length; - buf = kzalloc(max_size, GFP_KERNEL); - if (!buf) - return -ENOMEM; - } - - if (buf == NULL) - return -EINVAL; - - if ((*ppos > max_size) || - (*ppos + count > max_size) || - (*ppos + count < count) || - (count > uncopied_bytes)) - return -EINVAL; - - if (copy_from_user(buf + (*ppos), user_buf, count)) { - kfree(buf); - buf = NULL; - return -EFAULT; - } - - uncopied_bytes -= count; - *ppos += count; - - if (!uncopied_bytes) { - status = acpi_install_method(buf); - kfree(buf); - buf = NULL; - if (ACPI_FAILURE(status)) - return -EINVAL; - add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); - } - - return count; -} - -static const struct file_operations cm_fops = { - .write = cm_write, - .llseek = default_llseek, -}; - -static int __init acpi_custom_method_init(void) -{ - if (!acpi_debugfs_dir) - return -ENOENT; - - cm_dentry = debugfs_create_file("custom_method", S_IWUSR, - acpi_debugfs_dir, NULL, &cm_fops); - if (!cm_dentry) - return -ENODEV; - - return 0; -} +EXPORT_SYMBOL_GPL(acpi_debugfs_dir); void __init acpi_debugfs_init(void) { acpi_debugfs_dir = debugfs_create_dir("acpi", NULL); - - acpi_custom_method_init(); } -- cgit v1.2.3-70-g09d2