vfs: define kernel_read_file_id enumeration

To differentiate between the kernel_read_file() callers, this patch
defines a new enumeration named kernel_read_file_id and includes the
caller identifier as an argument.

Subsequent patches define READING_KEXEC_IMAGE, READING_KEXEC_INITRAMFS,
READING_FIRMWARE, READING_MODULE, and READING_POLICY.

Changelog v3:
- Replace the IMA specific enumeration with a generic one.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/exec.c b/fs/exec.c
index 6b6668baa44a39de5d387647b806fe55fb23d5ca..1138dc502c777f98ddff7bf34f20b6d5be82e21c 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -833,7 +833,7 @@ int kernel_read(struct file *file, loff_t offset,
 EXPORT_SYMBOL(kernel_read);
 
 int kernel_read_file(struct file *file, void **buf, loff_t *size,
-                    loff_t max_size)
+                    loff_t max_size, enum kernel_read_file_id id)
 {
        loff_t i_size, pos;
        ssize_t bytes = 0;
@@ -871,7 +871,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
                goto out;
        }
 
-       ret = security_kernel_post_read_file(file, *buf, i_size);
+       ret = security_kernel_post_read_file(file, *buf, i_size, id);
        if (!ret)
                *size = pos;
 

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9a83d82b61ac63493a3a3034e4d98a7c9207654d..aa84bcb9c3684c49ccc2b9417e63a6a06b9ea92c 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2576,8 +2576,13 @@ static inline void i_readcount_inc(struct inode *inode)
 #endif
 extern int do_pipe_flags(int *, int);
 
+enum kernel_read_file_id {
+       READING_MAX_ID
+};
+
 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
-extern int kernel_read_file(struct file *, void **, loff_t *, loff_t);
+extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
+                           enum kernel_read_file_id);
 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
 extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
 extern struct file * open_exec(const char *);

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index f82631cc72483f2b5fb9fd2cfb5a5268f53eae43..2337f33913c16f21ff514c93b15864276afed7c5 100644 (file)
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -567,6 +567,7 @@
  *     by the kernel.
  *     @buf pointer to buffer containing the file contents.
  *     @size length of the file contents.
+ *     @id kernel read file identifier
  *     Return 0 if permission is granted.
  * @task_fix_setuid:
  *     Update the module's state after setting one or more of the user
@@ -1464,7 +1465,8 @@ union security_list_options {
        int (*kernel_fw_from_file)(struct file *file, char *buf, size_t size);
        int (*kernel_module_request)(char *kmod_name);
        int (*kernel_module_from_file)(struct file *file);
-       int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size);
+       int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size,
+                                    enum kernel_read_file_id id);
        int (*task_fix_setuid)(struct cred *new, const struct cred *old,
                                int flags);
        int (*task_setpgid)(struct task_struct *p, pid_t pgid);

diff --git a/include/linux/security.h b/include/linux/security.h
index f30f5647d1e18a9cf533dd21ad33d319f7245849..b68ce94e4e00137bfa4b2dce2d28d56c47035f1a 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -28,6 +28,7 @@
 #include <linux/err.h>
 #include <linux/string.h>
 #include <linux/mm.h>
+#include <linux/fs.h>
 
 struct linux_binprm;
 struct cred;
@@ -301,7 +302,8 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_fw_from_file(struct file *file, char *buf, size_t size);
 int security_kernel_module_request(char *kmod_name);
 int security_kernel_module_from_file(struct file *file);
-int security_kernel_post_read_file(struct file *file, char *buf, loff_t size);
+int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
+                                  enum kernel_read_file_id id);
 int security_task_fix_setuid(struct cred *new, const struct cred *old,
                             int flags);
 int security_task_setpgid(struct task_struct *p, pid_t pgid);
@@ -868,7 +870,8 @@ static inline int security_kernel_module_from_file(struct file *file)
 }
 
 static inline int security_kernel_post_read_file(struct file *file,
-                                                char *buf, loff_t size)
+                                                char *buf, loff_t size,
+                                                enum kernel_read_file_id id)
 {
        return 0;
 }

diff --git a/security/security.c b/security/security.c
index c98dd6bf4ebdd7d6437284b6b5f0660a8193e678..5b96eabaafd4362c1158001f8427f98775e9f4a2 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -910,9 +910,10 @@ int security_kernel_module_from_file(struct file *file)
        return ima_module_check(file);
 }
 
-int security_kernel_post_read_file(struct file *file, char *buf, loff_t size)
+int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
+                                  enum kernel_read_file_id id)
 {
-       return call_int_hook(kernel_post_read_file, 0, file, buf, size);
+       return call_int_hook(kernel_post_read_file, 0, file, buf, size, id);
 }
 EXPORT_SYMBOL_GPL(security_kernel_post_read_file);