fs/locks: pass kernel struct flock to fcntl_getlk/setlk

This will make it easier to implement a sane compat fcntl syscall.

[ jlayton: fix undeclared identifiers in 32-bit fcntl64 syscall handler ]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 22 insertions, 5 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
index f4e7267d117f..ed4283d500a3 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -246,6 +246,8 @@ static int f_getowner_uids(struct file *filp, unsigned long arg)
 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
                 struct file *filp)
 {
+        void __user *argp = (void __user *)arg;
+        struct flock flock;
         long err = -EINVAL;
 
         switch (cmd) {
@@ -273,7 +275,11 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
         case F_OFD_GETLK:
 #endif
         case F_GETLK:
-                err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
+                if (copy_from_user(&flock, argp, sizeof(flock)))
+                        return -EFAULT;
+                err = fcntl_getlk(filp, cmd, &flock);
+                if (!err && copy_to_user(argp, &flock, sizeof(flock)))
+                        return -EFAULT;
                 break;
 #if BITS_PER_LONG != 32
         /* 32-bit arches must use fcntl64() */
@@ -283,7 +289,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
                 /* Fallthrough */
         case F_SETLK:
         case F_SETLKW:
-                err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
+                if (copy_from_user(&flock, argp, sizeof(flock)))
+                        return -EFAULT;
+                err = fcntl_setlk(fd, filp, cmd, &flock);
                 break;
         case F_GETOWN:
                 /*
@@ -383,7 +391,9 @@ out:
 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
                 unsigned long, arg)
 {       
+        void __user *argp = (void __user *)arg;
         struct fd f = fdget_raw(fd);
+        struct flock64 flock;
         long err = -EBADF;
 
         if (!f.file)
@@ -401,14 +411,21 @@ SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
         switch (cmd) {
         case F_GETLK64:
         case F_OFD_GETLK:
-                err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
+                err = -EFAULT;
+                if (copy_from_user(&flock, argp, sizeof(flock)))
+                        break;
+                err = fcntl_getlk64(f.file, cmd, &flock);
+                if (!err && copy_to_user(argp, &flock, sizeof(flock)))
+                        err = -EFAULT;
                 break;
         case F_SETLK64:
         case F_SETLKW64:
         case F_OFD_SETLK:
         case F_OFD_SETLKW:
-                err = fcntl_setlk64(fd, f.file, cmd,
-                                (struct flock64 __user *) arg);
+                err = -EFAULT;
+                if (copy_from_user(&flock, argp, sizeof(flock)))
+                        break;
+                err = fcntl_setlk64(fd, f.file, cmd, &flock);
                 break;
         default:
                 err = do_fcntl(fd, cmd, arg, f.file);