MISC.CHROOT.NOCHDIR : chroot without chdir

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chroot() is called, and there is at least one execution path in which there is no suitable subsequent call to chdir().

A subsequent call to chdir() is considered "suitable" if both of the following are true.

The number of lines of code executed before reaching the call to chdir() is less than the limit specified by configuration parameter MAX_CHROOT_CHDIR_DIST (factory setting is 20).

The call to chdir() is reached before the function in which chroot() was called returns.

This class is a strict subset of Use of chroot.

Class Name

chroot without chdir

Significance

security

Mnemonic

MISC.CHROOT.NOCHDIR

Categories

MisraC2023	MisraC2023:D.4.13	Functions which are designed to provide operations on a resource should be called in an appropriate sequence
Misra2012	Misra2012:D.4.13	Functions which are designed to provide operations on a resource should be called in an appropriate sequence
CWE	CWE:243	Creation of chroot Jail Without Changing Working Directory
	CWE:676	Use of Potentially Dangerous Function
CERT-C	CERT-C:POS05-C	Limit access to files by creating a jail
BSI	BSI:CHROOT-01
	BSI:CHROOT-02
	BSI:CHROOT-03

Availability

Available for C and C++.

Enabling

Checks for this warning class are disabled by default. To enable them, add the following WARNING_FILTER rule to the project configuration file.

WARNING_FILTER += allow class="chroot without chdir"

To enable all BSI-related classes, including all BSI-specific BADFUNC classes, use the bsi configuration preset.

#include <unistd.h>
#include <stdio.h>

int chroot_no_chdir(const char *fname, char *buf){
    FILE *localfile;
    int bytesread=0;
    if (chroot("/downloaddir")==-1){return 0;} /* 'chroot without chdir' warning issued here:
                                                *  there is at least one path on which chdir() is not subsequently called */
    if (fname){
        if (localfile = fopen(fname, "r")){
            bytesread = fread(buf, 1, sizeof(buf), localfile);
            fclose(localfile);
        }
        if (chdir("/")==-1){return 0-bytesread;}        /* chdir() is only called if fname!=NULL - not on all paths */
    }
    return bytesread;
}

The following configuration file parameters affect checks for this warning class.

MISC.CHROOT.NOCHDIR : chroot without chdir

Summary

Properties

Example

Relevant Configuration File Parameters