1  /* Overflow tests for stat, statfs, and lseek functions.
       2     Copyright (C) 2020-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library.  If not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <sys/stat.h>
      20  #include <sys/statfs.h>
      21  
      22  /* Test for overflows of structures where we ask the kernel to fill them
      23     in with standard 64-bit syscalls but return them through APIs that
      24     only expose the low 32 bits of some fields.  */
      25  
      26  static inline off_t lseek_overflow (loff_t res)
      27  {
      28    off_t retval = (off_t) res;
      29    if (retval == res)
      30      return retval;
      31  
      32    __set_errno (EOVERFLOW);
      33    return (off_t) -1;
      34  }
      35  
      36  static inline int stat_overflow (struct stat *buf)
      37  {
      38  #if defined __INO_T_MATCHES_INO64_T || !STAT_IS_KERNEL_STAT
      39    return 0;
      40  #else
      41    if (buf->__st_ino_pad == 0 && buf->__st_size_pad == 0
      42        && buf->__st_blocks_pad == 0)
      43      return 0;
      44  
      45    __set_errno (EOVERFLOW);
      46    return -1;
      47  #endif
      48  }
      49  
      50  /* Note that f_files and f_ffree may validly be a sign-extended -1.  */
      51  static inline int statfs_overflow (struct statfs *buf)
      52  {
      53  #if __STATFS_MATCHES_STATFS64 || !STAT_IS_KERNEL_STAT
      54    return 0;
      55  #else
      56    if (buf->__f_blocks_pad == 0 && buf->__f_bfree_pad == 0
      57        && buf->__f_bavail_pad == 0
      58        && (buf->__f_files_pad == 0
      59  	  || (buf->f_files == -1U && buf->__f_files_pad == -1))
      60        && (buf->__f_ffree_pad == 0
      61  	  || (buf->f_ffree == -1U && buf->__f_ffree_pad == -1)))
      62      return 0;
      63  
      64    __set_errno (EOVERFLOW);
      65    return -1;
      66  #endif
      67  }