Bug 1109263 (CVE-2014-4043)

Summary: CVE-2014-4043 glibc: posix_spawn_file_actions_addopen fails to copy the path argument
Product: [Other] Security Response Reporter: Vasyl Kaigorodov <vkaigoro>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: ashankar, carnil, codonell, fweimer, jakub, mnewsome, osoukup, pfrankli
Target Milestone: ---Keywords: Reopened, Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: glibc 2.20 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-06-15 15:03:59 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1109745    
Bug Blocks: 1109746    

Description Vasyl Kaigorodov 2014-06-13 14:10:19 UTC
posix_spawn_file_actions_addopen in glibc fails to copy the path argument.
Per the specification (http://pubs.opengroup.org/onlinepubs/000095399/functions/posix_spawn_file_actions_addclose.html) it is supposed to.
The result of not copying is that programs can easily trigger use-after-free bugs,
or other situations where the path is mutated. The following program demonstrates this issue:

#include <string.h>
#include <assert.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <spawn.h>
#include <stdio.h>

extern char *const *environ;

int main() {
    int res;
    posix_spawn_file_actions_t fa;

    char *orig_path = "/tmp/afddsa";
    char *path = malloc(strlen(orig_path) + 1);
    strcpy(path, orig_path);
    path[strlen(orig_path)] = '\0';

    res = posix_spawn_file_actions_addopen(
        &fa, 1, path, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
    assert(res == 0);

    memset(path, 0, strlen(orig_path));

    char *argv[] = {"/bin/echo", NULL};
    pid_t pid;
    res = posix_spawn(
    assert(res == 0);
    int status;
    wait4(pid, &status, 0, NULL);
    printf("%d\n", WEXITSTATUS(status));

This bug was jointly discovered by David Reid, Alex Gaynor, and Glyph Lefkowitz.

Issue is fixed in glibc 2.20:
Recommended additional commit for backporting: 

External references:


Comment 2 Vasyl Kaigorodov 2014-06-16 10:00:48 UTC
Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1109745]

Comment 3 Vasyl Kaigorodov 2014-06-16 11:12:53 UTC

The Red Hat Security Response Team has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates for Red Hat Enterprise Linux 4 and 5. A future update may address this flaw in Red Hat Enterprise Linux 6 or 7. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Comment 6 Product Security DevOps Team 2021-06-15 15:03:59 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):