proc: maps protection

[deliverable/linux.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index ec158dd02b3ac2b758fbbf527820c1f0f83a486a..17f7a7ee6c5e14aa00e2b9b8a999a8cfa89d21d9 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -64,6 +64,7 @@
 #include <linux/smp_lock.h>
 #include <linux/rcupdate.h>
 #include <linux/kallsyms.h>
+#include <linux/module.h>
 #include <linux/mount.h>
 #include <linux/security.h>
 #include <linux/ptrace.h>
@@ -123,6 +124,9 @@ struct pid_entry {
                NULL, &proc_info_file_operations,       \
                { .proc_read = &proc_##OTYPE } )
 
+int maps_protect;
+EXPORT_SYMBOL(maps_protect);
+
 static struct fs_struct *get_fs_struct(struct task_struct *task)
 {
        struct fs_struct *fs;
@@ -1447,11 +1451,29 @@ static const struct file_operations proc_fd_operations = {
        .readdir        = proc_readfd,
 };
 
+/*
+ * /proc/pid/fd needs a special permission handler so that a process can still
+ * access /proc/self/fd after it has executed a setuid().
+ */
+static int proc_fd_permission(struct inode *inode, int mask,
+                               struct nameidata *nd)
+{
+       int rv;
+
+       rv = generic_permission(inode, mask, NULL);
+       if (rv == 0)
+               return 0;
+       if (task_pid(current) == proc_pid(inode))
+               rv = 0;
+       return rv;
+}
+
 /*
  * proc directories can do almost nothing..
  */
 static const struct inode_operations proc_fd_inode_operations = {
        .lookup         = proc_lookupfd,
+       .permission     = proc_fd_permission,
        .setattr        = proc_setattr,
 };