CERT C++: MSC33-C

Do not pass invalid data to the asctime() function

expand all in page

Description

Do not pass invalid data to the asctime() function. 1

Polyspace Implementation

The rule checker checks for Use of obsolete standard function.

Examples

expand all

Issue

Use of obsolete standard function detects calls to standard function routines that are considered legacy, removed, deprecated, or obsolete by C/C++ coding standards.

Obsolete FunctionStandardsRiskReplacement Function
asctime Deprecated in POSIX.1-2008Not thread-safe. strftime or asctime_s
asctime_r Deprecated in POSIX.1-2008Implementation based on unsafe function sprintf. strftime or asctime_s
bcmp

Deprecated in 4.3BSD

Marked as legacy in POSIX.1-2001.

Returns from function after finding the first differing byte, making it vulnerable to timing attacks. memcmp
bcopy

Deprecated in 4.3BSD

Marked as legacy in POSIX.1-2001.

Returns from function after finding the first differing byte, making it vulnerable to timing attacks. memcpy or memmove
brk and sbrkMarked as legacy in SUSv2 and POSIX.1-2001.  malloc
bsd_signal Removed in POSIX.1-2008  sigaction
bzero Marked as legacy in POSIX.1-2001. Removed in POSIX.1-2008.  memset
ctime Deprecated in POSIX.1-2008Not thread-safe. strftime or asctime_s
ctime_r Deprecated in POSIX.1-2008Implementation based on unsafe function sprintf. strftime or asctime_s
cuserid Removed in POSIX.1-2001.Not reentrant. Precise functionality not standardized causing portability issues. getpwuid
ecvt and fcvtMarked as legacy in POSIX.1-2001. Removed in POSIX.1-2008Not reentrant snprintf
ecvt_r and fcvt_rMarked as legacy in POSIX.1-2001. Removed in POSIX.1-2008  snprintf
ftime Removed in POSIX.1-2008  time, gettimeofday, clock_gettime
gamma, gammaf, gammalFunction not specified in any standard because of historical variationsPortability issues. tgamma, lgamma
gcvt Marked as legacy in POSIX.1-2001. Removed in POSIX.1-2008.  snprintf
getcontext Removed in POSIX.1-2008.Portability issues. Use POSIX thread instead.
getdtablesize BSD API function not included in POSIX.1-2001Portability issues. sysconf( _SC_OPEN_MAX )
gethostbyaddr Removed in POSIX.1-2008Not reentrant getaddrinfo
gethostbyname Removed in POSIX.1-2008Not reentrant getnameinfo
getpagesize BSD API function not included in POSIX.1-2001Portability issues. sysconf( _SC_PAGESIZE )
getpass Removed in POSIX.1-2001.Not reentrant. getpwuid
getw Not present in POSIX.1-2001.  fread
getwd Marked legacy in POSIX.1-2001. Removed in POSIX.1-2008.  getcwd
index Marked as legacy in POSIX.1-2001. Removed in POSIX.1-2008.  strchr
makecontext Removed in POSIX.1-2008.Portability issues. Use POSIX thread instead.
memalign Appears in SunOS 4.1.3. Not in 4.4 BSD or POSIX.1-2001  posix_memalign
mktemp Removed in POSIX.1-2008.Generated names are predictable and can cause a race condition. mkstemp removes race risk
pthread_attr_getstackaddr and pthread_attr_setstackaddr  Ambiguities in the specification of the stackaddr attribute cause portability issues pthread_attr_getstack and pthread_attr_setstack
putw Not present in POSIX.1-2001.Portability issues. fwrite
qecvt and qfcvtMarked as legacy in POSIX.1-2001, removed in POSIX.1-2008  snprintf
qecvt_r and qfcvt_rMarked as legacy in POSIX.1-2001, removed in POSIX.1-2008  snprintf
rand_r Marked as obsolete in POSIX.1-2008  
re_comp BSD API functionPortability issues regcomp
re_exes BSD API functionPortability issues regexec
rindex Marked as legacy in POSIX.1-2001. Removed in POSIX.1-2008.  strrchr
scalb Removed in POSIX.1-2008  scalbln, scalblnf, or scalblnl
sigblock 4.3BSD signal API whose origin is unclear  sigprocmask
sigmask 4.3BSD signal API whose origin is unclear  sigprocmask
sigsetmask 4.3BSD signal API whose origin is unclear  sigprocmask
sigstack Interface is obsolete and not implemented on most platforms.Portability issues. sigaltstack
sigvec 4.3BSD signal API whose origin is unclear  sigaction
swapcontext Removed in POSIX.1-2008Portability issues. Use POSIX threads.
tmpnam and tmpnam_rMarked as obsolete in POSIX.1-2008.This function generates a different string each time it is called, up to TMP_MAX times. If it is called more than TMP_MAX times, the behavior is implementation-defined. mkstemp, tmpfile
ttyslot Removed in POSIX.1-2001.  
ualarm Marked as legacy in POSIX.1-2001. Removed in POSIX.1-2008.Errors are under-specified setitimer or POSIX timer_create
usleep Removed in POSIX.1-2008.  nanosleep
utime SVr4, POSIX.1-2001. POSIX.1-2008 marks as obsolete.  
valloc

Marked as obsolete in 4.3BSD.

Marked as legacy in SUSv2.

Removed from POSIX.1-2001

  posix_memalign
vfork

Removed from POSIX.1-2008

Under-specified in previous standards. fork
wcswcs This function was not included in the final ISO/IEC 9899:1990/Amendment 1:1995 (E).   wcsstr
WinExec WinAPI provides this function only for 16-bit Windows compatibility.  CreateProcess
LoadModule WinAPI provides this function only for 16-bit Windows compatibility.  CreateProcess
Fix

The fix depends on the root cause of the defect. Often the result details show a sequence of events that led to the defect. You can implement the fix on any event in the sequence. If the result details do not show the event history, you can trace back using right-click options in the source code and see previous related events. See also Interpret Polyspace Bug Finder Results in Polyspace Platform User Interface.

See examples of fixes below.

If you do not want to fix the issue, add comments to your result or code to avoid another review. See:

Example - Printing Out Time
#include <stdio.h>
#include <time.h> 

void timecheck_bad(int argc, char *argv[])
{
    time_t ticks; 

    ticks = time(NULL);
    printf("%.24s\r\n", ctime(&ticks)); //Noncompliant
}

In this example, the function ctime formats the current time and prints it out. However, ctime was removed after C99 because it does not work on multithreaded programs.

Correction — Different Time Function

One possible correction is to use strftime instead because this function uses a set buffer size.

#include <stdio.h>
#include <string.h>
#include <time.h> 

void timecheck_good(int argc, char *argv[])
{
    char outBuff[1025];
    time_t ticks; 
    struct tm * timeinfo;
    
    memset(outBuff, 0, sizeof(outBuff)); 
    
    ticks = time(NULL);
    timeinfo = localtime(&ticks);
    strftime(outBuff,sizeof(outBuff),"%I:%M%p.",timeinfo);
    fprintf(stdout, outBuff);
}

Check Information

Group: 49. Miscellaneous (MSC)
PQL Name: std.cert_cpp.MSC33_C

Version History

Introduced in R2019a

See Also

Topics

External Websites

1 This software has been created by MathWorks incorporating portions of: the “SEI CERT-C Website,” © 2017 Carnegie Mellon University, the SEI CERT-C++ Web site © 2017 Carnegie Mellon University, ”SEI CERT C Coding Standard – Rules for Developing safe, Reliable and Secure systems – 2016 Edition,” © 2016 Carnegie Mellon University, and “SEI CERT C++ Coding Standard – Rules for Developing safe, Reliable and Secure systems in C++ – 2016 Edition” © 2016 Carnegie Mellon University, with special permission from its Software Engineering Institute.

ANY MATERIAL OF CARNEGIE MELLON UNIVERSITY AND/OR ITS SOFTWARE ENGINEERING INSTITUTE CONTAINED HEREIN IS FURNISHED ON AN "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY KIND, EITHER EXPRESSED OR IMPLIED, AS TO ANY MATTER INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR PURPOSE OR MERCHANTABILITY, EXCLUSIVITY, OR RESULTS OBTAINED FROM USE OF THE MATERIAL. CARNEGIE MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT.

This software and associated documentation has not been reviewed nor is it endorsed by Carnegie Mellon University or its Software Engineering Institute.