fcntl: move compat syscalls from compat.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 157 insertions, 0 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
index be8fbe289087..8bd81c2e89b2 100644
--- 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] = {