Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[karo-tx-linux.git] / fs / fcntl.c

diff --git a/fs/fcntl.c b/fs/fcntl.c
index de1b16bb6a29c02ee5c2856e5c5411f978716b4f..f4e7267d117fb83b69f6f5be2305fb8b375077c8 100644 (file)
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -23,6 +23,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/shmem_fs.h>
+#include <linux/compat.h>
 
 #include <asm/poll.h>
 #include <asm/siginfo.h>
@@ -420,6 +421,162 @@ out:
 }
 #endif
 
+#ifdef CONFIG_COMPAT
+static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
+{
+       if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
+           __get_user(kfl->l_type, &ufl->l_type) ||
+           __get_user(kfl->l_whence, &ufl->l_whence) ||
+           __get_user(kfl->l_start, &ufl->l_start) ||
+           __get_user(kfl->l_len, &ufl->l_len) ||
+           __get_user(kfl->l_pid, &ufl->l_pid))
+               return -EFAULT;
+       return 0;
+}
+
+static int put_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
+{
+       if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
+           __put_user(kfl->l_type, &ufl->l_type) ||
+           __put_user(kfl->l_whence, &ufl->l_whence) ||
+           __put_user(kfl->l_start, &ufl->l_start) ||
+           __put_user(kfl->l_len, &ufl->l_len) ||
+           __put_user(kfl->l_pid, &ufl->l_pid))
+               return -EFAULT;
+       return 0;
+}
+
+#ifndef HAVE_ARCH_GET_COMPAT_FLOCK64
+static int get_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
+{
+       if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
+           __get_user(kfl->l_type, &ufl->l_type) ||
+           __get_user(kfl->l_whence, &ufl->l_whence) ||
+           __get_user(kfl->l_start, &ufl->l_start) ||
+           __get_user(kfl->l_len, &ufl->l_len) ||
+           __get_user(kfl->l_pid, &ufl->l_pid))
+               return -EFAULT;
+       return 0;
+}
+#endif
+
+#ifndef HAVE_ARCH_PUT_COMPAT_FLOCK64
+static int put_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
+{
+       if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
+           __put_user(kfl->l_type, &ufl->l_type) ||
+           __put_user(kfl->l_whence, &ufl->l_whence) ||
+           __put_user(kfl->l_start, &ufl->l_start) ||
+           __put_user(kfl->l_len, &ufl->l_len) ||
+           __put_user(kfl->l_pid, &ufl->l_pid))
+               return -EFAULT;
+       return 0;
+}
+#endif
+
+static unsigned int
+convert_fcntl_cmd(unsigned int cmd)
+{
+       switch (cmd) {
+       case F_GETLK64:
+               return F_GETLK;
+       case F_SETLK64:
+               return F_SETLK;
+       case F_SETLKW64:
+               return F_SETLKW;
+       }
+
+       return cmd;
+}
+
+COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
+                      compat_ulong_t, arg)
+{
+       mm_segment_t old_fs;
+       struct flock f;
+       long ret;
+       unsigned int conv_cmd;
+
+       switch (cmd) {
+       case F_GETLK:
+       case F_SETLK:
+       case F_SETLKW:
+               ret = get_compat_flock(&f, compat_ptr(arg));
+               if (ret != 0)
+                       break;
+               old_fs = get_fs();
+               set_fs(KERNEL_DS);
+               ret = sys_fcntl(fd, cmd, (unsigned long)&f);
+               set_fs(old_fs);
+               if (cmd == F_GETLK && ret == 0) {
+                       /* GETLK was successful and we need to return the data...
+                        * but it needs to fit in the compat structure.
+                        * l_start shouldn't be too big, unless the original
+                        * start + end is greater than COMPAT_OFF_T_MAX, in which
+                        * case the app was asking for trouble, so we return
+                        * -EOVERFLOW in that case.
+                        * l_len could be too big, in which case we just truncate it,
+                        * and only allow the app to see that part of the conflicting
+                        * lock that might make sense to it anyway
+                        */
+
+                       if (f.l_start > COMPAT_OFF_T_MAX)
+                               ret = -EOVERFLOW;
+                       if (f.l_len > COMPAT_OFF_T_MAX)
+                               f.l_len = COMPAT_OFF_T_MAX;
+                       if (ret == 0)
+                               ret = put_compat_flock(&f, compat_ptr(arg));
+               }
+               break;
+
+       case F_GETLK64:
+       case F_SETLK64:
+       case F_SETLKW64:
+       case F_OFD_GETLK:
+       case F_OFD_SETLK:
+       case F_OFD_SETLKW:
+               ret = get_compat_flock64(&f, compat_ptr(arg));
+               if (ret != 0)
+                       break;
+               old_fs = get_fs();
+               set_fs(KERNEL_DS);
+               conv_cmd = convert_fcntl_cmd(cmd);
+               ret = sys_fcntl(fd, conv_cmd, (unsigned long)&f);
+               set_fs(old_fs);
+               if ((conv_cmd == F_GETLK || conv_cmd == F_OFD_GETLK) && ret == 0) {
+                       /* need to return lock information - see above for commentary */
+                       if (f.l_start > COMPAT_LOFF_T_MAX)
+                               ret = -EOVERFLOW;
+                       if (f.l_len > COMPAT_LOFF_T_MAX)
+                               f.l_len = COMPAT_LOFF_T_MAX;
+                       if (ret == 0)
+                               ret = put_compat_flock64(&f, compat_ptr(arg));
+               }
+               break;
+
+       default:
+               ret = sys_fcntl(fd, cmd, arg);
+               break;
+       }
+       return ret;
+}
+
+COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
+                      compat_ulong_t, arg)
+{
+       switch (cmd) {
+       case F_GETLK64:
+       case F_SETLK64:
+       case F_SETLKW64:
+       case F_OFD_GETLK:
+       case F_OFD_SETLK:
+       case F_OFD_SETLKW:
+               return -EINVAL;
+       }
+       return compat_sys_fcntl64(fd, cmd, arg);
+}
+#endif
+
 /* Table to convert sigio signal codes into poll band bitmaps */
 
 static const long band_table[NSIGPOLL] = {