Bug Summary

File:src/lib/libc/stdlib/system.c
Warning:line 56, column 17
Call to function 'vfork' is insecure as it can lead to denial of service situations in the parent process. Replace calls to vfork with calls to the safer 'posix_spawn' function

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name system.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/lib/libc/obj -resource-dir /usr/local/lib/clang/13.0.0 -include namespace.h -I /usr/src/lib/libc/include -I /usr/src/lib/libc/hidden -D __LIBC__ -D APIWARN -D YP -I /usr/src/lib/libc/yp -I /usr/src/lib/libc -I /usr/src/lib/libc/gdtoa -I /usr/src/lib/libc/arch/amd64/gdtoa -D INFNAN_CHECK -D MULTIPLE_THREADS -D NO_FENV_H -D USE_LOCALE -I /usr/src/lib/libc -I /usr/src/lib/libc/citrus -D RESOLVSORT -D FLOATING_POINT -D PRINTF_WIDE_CHAR -D SCANF_WIDE_CHAR -D FUTEX -D PIC -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/lib/libc/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/lib/libc/stdlib/system.c
1/* $OpenBSD: system.c,v 1.12 2016/03/13 18:34:21 guenther Exp $ */
2/*
3 * Copyright (c) 1988 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/types.h>
32#include <sys/wait.h>
33#include <errno(*__errno()).h>
34#include <signal.h>
35#include <stdlib.h>
36#include <unistd.h>
37#include <paths.h>
38
39int
40system(const char *command)
41{
42 pid_t pid, cpid;
43 struct sigaction intsave, quitsave;
44 sigset_t mask, omask;
45 int pstat;
46 char *argp[] = {"sh", "-c", NULL((void *)0), NULL((void *)0)};
47
48 if (!command) /* just checking... */
49 return(1);
50
51 argp[2] = (char *)command;
52
53 sigemptyset(&mask);
54 sigaddset(&mask, SIGCHLD20);
55 sigprocmask(SIG_BLOCK1, &mask, &omask);
56 switch (cpid = vfork()) {
Call to function 'vfork' is insecure as it can lead to denial of service situations in the parent process. Replace calls to vfork with calls to the safer 'posix_spawn' function
57 case -1: /* error */
58 sigprocmask(SIG_SETMASK3, &omask, NULL((void *)0));
59 return(-1);
60 case 0: /* child */
61 sigprocmask(SIG_SETMASK3, &omask, NULL((void *)0));
62 execve(_PATH_BSHELL"/bin/sh", argp, environ);
63 _exit(127);
64 }
65
66 sigaction(SIGINT2, NULL((void *)0), &intsave);
67 sigaction(SIGQUIT3, NULL((void *)0), &quitsave);
68 do {
69 pid = waitpid(cpid, &pstat, 0);
70 } while (pid == -1 && errno(*__errno()) == EINTR4);
71 sigprocmask(SIG_SETMASK3, &omask, NULL((void *)0));
72 sigaction(SIGINT2, &intsave, NULL((void *)0));
73 sigaction(SIGQUIT3, &quitsave, NULL((void *)0));
74 return (pid == -1 ? -1 : pstat);
75}
76DEF_STRONG(system)__asm__(".global " "system" " ; " "system" " = " "_libc_system"
)
;