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authorDmitry Kasatkin <d.kasatkin@samsung.com>2014-11-05 17:01:12 +0200
committerMimi Zohar <zohar@linux.vnet.ibm.com>2014-11-17 23:09:18 -0500
commite3c4abbfa97ed0b7aed36f18b32911ccf76d52c2 (patch)
tree2dabccd9c08945c45c701bb42c02959644011066 /security/integrity/iint.c
parentima: added support for new kernel cmdline parameter ima_template_fmt (diff)
downloadlinux-dev-e3c4abbfa97ed0b7aed36f18b32911ccf76d52c2.tar.xz
linux-dev-e3c4abbfa97ed0b7aed36f18b32911ccf76d52c2.zip
integrity: define a new function integrity_read_file()
This patch defines a new function called integrity_read_file() to read file from the kernel into a buffer. Subsequent patches will read a file containing the public keys and load them onto the IMA keyring. This patch moves and renames ima_kernel_read(), the non-security checking version of kernel_read(), to integrity_kernel_read(). Changes in v3: * Patch descriptions improved (Mimi) * Add missing cast (kbuild test robot) Changes in v2: * configuration option removed * function declared as '__init' Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Diffstat (limited to 'security/integrity/iint.c')
-rw-r--r--security/integrity/iint.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index cc3eb4de18a1..dbee618526b6 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -19,6 +19,8 @@
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/rbtree.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
#include "integrity.h"
static struct rb_root integrity_iint_tree = RB_ROOT;
@@ -167,3 +169,79 @@ static int __init integrity_iintcache_init(void)
return 0;
}
security_initcall(integrity_iintcache_init);
+
+
+/*
+ * integrity_kernel_read - read data from the file
+ *
+ * This is a function for reading file content instead of kernel_read().
+ * It does not perform locking checks to ensure it cannot be blocked.
+ * It does not perform security checks because it is irrelevant for IMA.
+ *
+ */
+int integrity_kernel_read(struct file *file, loff_t offset,
+ char *addr, unsigned long count)
+{
+ mm_segment_t old_fs;
+ char __user *buf = (char __user *)addr;
+ ssize_t ret = -EINVAL;
+
+ if (!(file->f_mode & FMODE_READ))
+ return -EBADF;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ if (file->f_op->read)
+ ret = file->f_op->read(file, buf, count, &offset);
+ else if (file->f_op->aio_read)
+ ret = do_sync_read(file, buf, count, &offset);
+ else if (file->f_op->read_iter)
+ ret = new_sync_read(file, buf, count, &offset);
+ set_fs(old_fs);
+ return ret;
+}
+
+/*
+ * integrity_read_file - read entire file content into the buffer
+ *
+ * This is function opens a file, allocates the buffer of required
+ * size, read entire file content to the buffer and closes the file
+ *
+ * It is used only by init code.
+ *
+ */
+int __init integrity_read_file(const char *path, char **data)
+{
+ struct file *file;
+ loff_t size;
+ char *buf;
+ int rc = -EINVAL;
+
+ file = filp_open(path, O_RDONLY, 0);
+ if (IS_ERR(file)) {
+ rc = PTR_ERR(file);
+ pr_err("Unable to open file: %s (%d)", path, rc);
+ return rc;
+ }
+
+ size = i_size_read(file_inode(file));
+ if (size <= 0)
+ goto out;
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ rc = integrity_kernel_read(file, 0, buf, size);
+ if (rc < 0)
+ kfree(buf);
+ else if (rc != size)
+ rc = -EIO;
+ else
+ *data = buf;
+out:
+ fput(file);
+ return rc;
+}