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Fixed

LIN1021-3814 : Bug in mq_timedreceive in glibc 2.33 (and later)

Created: Jun 21, 2022    Updated: Nov 10, 2022
Resolved Date: Oct 17, 2022
Found In Version: 10.21.20.14
Fix Version: 10.21.20.14
Severity: Standard
Applicable for: Wind River Linux LTS 21
Component/s: Userspace

Description

The mq_timedreceive code in glibc-2.33/sysdeps/unix/sysv/linux/mq_timedreceive.c does this:

ssize_t
{_}{{_}}mq_timedreceive_time64 (mqd_t mqdes, char *\{_}_restrict msg_ptr, size_t msg_len,
                          unsigned int *__restrict msg_prio,
                          const struct {_}{{_}}timespec64 *\{_}_restrict abs_timeout)
{
#ifndef __NR_mq_timedreceive_time64
 # define __NR_mq_timedreceive_time64 __NR_mq_timedreceive
#endif
  int ret = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
                            msg_prio, abs_timeout);

#ifndef __ASSUME_TIME64_SYSCALLS
  if (ret == 0 || errno != ENOSYS)
    return ret;

  struct timespec ts32;
  if (abs_timeout != NULL)
    {
      if (! in_time_t_range (abs_timeout->tv_sec))
       

{           __set_errno (EOVERFLOW);           return -1;         }

      ts32 = valid_timespec64_to_timespec (*abs_timeout);
    }

  ret = SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len, msg_prio,
                        abs_timeout != NULL ? &ts32 : NULL);
#endif

  return ret;
}

This test is wrong:

  if (ret == 0 || errno != ENOSYS)
    return ret;

That test would be correct if mq_timedreceive returned 0 on success, as is the case for mq_timedsend.  However, mq_timedreceive actually returns the number of bytes read, so the correct test is either

  If (ret >= 0 || errno != ENOSYS)
     return ret;

or more readable and less error-prone (IMO):

  if (ret != -1 || errno != ENOSYS)
    return ret;
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