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perform system() arg processing before fork
[perl5.git] / taint.c
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1/* taint.c
2 *
663f364b 3 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
1129b882 4 * 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
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5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Artistic License, as specified in the README file.
8 *
9 */
10
a0d0e21e 11/*
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12 * '...we will have peace, when you and all your works have perished--and
13 * the works of your dark master to whom you would deliver us. You are a
cdad3b53 14 * liar, Saruman, and a corrupter of men's hearts.' --Théoden
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15 *
16 * [p.580 of _The Lord of the Rings_, III/x: "The Voice of Saruman"]
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17 */
18
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19/* This file contains a few functions for handling data tainting in Perl
20 */
21
463ee0b2 22#include "EXTERN.h"
864dbfa3 23#define PERL_IN_TAINT_C
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24#include "perl.h"
25
26void
e1c41806 27Perl_taint_proper(pTHX_ const char *f, const char *const s)
79072805 28{
26e623cf 29#if defined(HAS_SETEUID) && defined(DEBUGGING)
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30 PERL_ARGS_ASSERT_TAINT_PROPER;
31
26e623cf 32 {
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33 const Uid_t uid = PerlProc_getuid();
34 const Uid_t euid = PerlProc_geteuid();
26e623cf 35
8b225b9c 36#if Uid_t_sign == 1 /* uid_t is unsigned. */
8772537c 37 DEBUG_u(PerlIO_printf(Perl_debug_log,
147e3846 38 "%s %d %" UVuf " %" UVuf "\n",
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39 s, TAINT_get, (UV)uid, (UV)euid));
40#else /* uid_t is signed (Uid_t_sign == -1), or don't know. */
41 DEBUG_u(PerlIO_printf(Perl_debug_log,
147e3846 42 "%s %d %" IVdf " %" IVdf "\n",
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43 s, TAINT_get, (IV)uid, (IV)euid));
44#endif
26e623cf 45 }
a52cb5f7 46#endif
1e422769 47
284167a5 48 if (TAINT_get) {
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49 const char *ug;
50
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51 if (!f)
52 f = PL_no_security;
985213f2 53 if (PerlProc_getuid() != PerlProc_geteuid())
bbce6d69 54 ug = " while running setuid";
985213f2 55 else if (PerlProc_getgid() != PerlProc_getegid())
bbce6d69 56 ug = " while running setgid";
284167a5 57 else if (TAINT_WARN_get)
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58 ug = " while running with -t switch";
59 else
bbce6d69 60 ug = " while running with -T switch";
5d37acd6 61
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62 /* XXX because taint_proper adds extra format args, we can't
63 * get the caller to check properly; o we just silence the warning
64 * and hope the callers aren't naughty */
65 GCC_DIAG_IGNORE(-Wformat-nonliteral);
284167a5 66 if (PL_unsafe || TAINT_WARN_get) {
9b387841 67 Perl_ck_warner_d(aTHX_ packWARN(WARN_TAINT), f, s, ug);
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68 }
69 else {
70 Perl_croak(aTHX_ f, s, ug);
71 }
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72 GCC_DIAG_RESTORE;
73
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74 }
75}
76
77void
864dbfa3 78Perl_taint_env(pTHX)
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79{
80 SV** svp;
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81 const char* const *e;
82 static const char* const misc_env[] = {
7bac28a0 83 "IFS", /* most shells' inter-field separators */
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84 "CDPATH", /* ksh dain bramage #1 */
85 "ENV", /* ksh dain bramage #2 */
86 "BASH_ENV", /* bash dain bramage -- I guess it's contagious */
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87#ifdef WIN32
88 "PERL5SHELL", /* used for system() on Windows */
89#endif
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90 NULL
91 };
1e422769 92
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93 /* Don't bother if there's no *ENV glob */
94 if (!PL_envgv)
142393a6 95 return;
284167a5 96 /* If there's no %ENV hash or if it's not magical, croak, because
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97 * it probably doesn't reflect the actual environment */
98 if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
daba3364 99 && mg_find((const SV *)GvHV(PL_envgv), PERL_MAGIC_env))) {
284167a5 100 const bool was_tainted = TAINT_get;
8772537c 101 const char * const name = GvENAME(PL_envgv);
284167a5 102 TAINT;
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103 if (strEQ(name,"ENV"))
104 /* hash alias */
105 taint_proper("%%ENV is aliased to %s%s", "another variable");
106 else
107 /* glob alias: report it in the error message */
108 taint_proper("%%ENV is aliased to %%%s%s", name);
109 /* this statement is reached under -t or -U */
284167a5 110 TAINT_set(was_tainted);
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111#ifdef NO_TAINT_SUPPORT
112 PERL_UNUSED_VAR(was_tainted);
113#endif
c038024b 114 }
142393a6 115
1e422769 116#ifdef VMS
82f1aded 117 {
1e422769 118 int i = 0;
0dc443ab 119 char name[10 + TYPE_DIGITS(int)] = "DCL$PATH";
86c11942 120 STRLEN len = 8; /* strlen(name) */
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121
122 while (1) {
19742f39 123 MAGIC* mg;
1e422769 124 if (i)
03f39617 125 len = my_snprintf(name, sizeof name, "DCL$PATH;%d", i);
86c11942 126 svp = hv_fetch(GvHVn(PL_envgv), name, len, FALSE);
6b88bc9c 127 if (!svp || *svp == &PL_sv_undef)
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128 break;
129 if (SvTAINTED(*svp)) {
130 TAINT;
131 taint_proper("Insecure %s%s", "$ENV{DCL$PATH}");
132 }
c038024b 133 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
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134 TAINT;
135 taint_proper("Insecure directory in %s%s", "$ENV{DCL$PATH}");
136 }
137 i++;
138 }
82f1aded 139 }
1e422769 140#endif /* VMS */
79072805 141
a4fc7abc 142 svp = hv_fetchs(GvHVn(PL_envgv),"PATH",FALSE);
1e422769 143 if (svp && *svp) {
19742f39 144 MAGIC* mg;
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145 if (SvTAINTED(*svp)) {
146 TAINT;
bbce6d69 147 taint_proper("Insecure %s%s", "$ENV{PATH}");
1e422769 148 }
c038024b 149 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
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150 TAINT;
151 taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
152 }
79072805 153 }
79072805 154
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155#ifndef VMS
156 /* tainted $TERM is okay if it contains no metachars */
a4fc7abc 157 svp = hv_fetchs(GvHVn(PL_envgv),"TERM",FALSE);
c90c0ff4 158 if (svp && *svp && SvTAINTED(*svp)) {
8b6b16e7 159 STRLEN len;
284167a5 160 const bool was_tainted = TAINT_get;
cfd0369c 161 const char *t = SvPV_const(*svp, len);
8772537c 162 const char * const e = t + len;
9a9b5ec9 163
284167a5 164 TAINT_set(was_tainted);
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165#ifdef NO_TAINT_SUPPORT
166 PERL_UNUSED_VAR(was_tainted);
167#endif
0eb30aeb 168 if (t < e && isWORDCHAR(*t))
c90c0ff4 169 t++;
0eb30aeb 170 while (t < e && (isWORDCHAR(*t) || strchr("-_.+", *t)))
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171 t++;
172 if (t < e) {
173 TAINT;
174 taint_proper("Insecure $ENV{%s}%s", "TERM");
175 }
176 }
177#endif /* !VMS */
178
7bac28a0 179 for (e = misc_env; *e; e++) {
0bd48802 180 SV * const * const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
3280af22 181 if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
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182 TAINT;
183 taint_proper("Insecure $ENV{%s}%s", *e);
184 }
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185 }
186}
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187
188/*
14d04a33 189 * ex: set ts=8 sts=4 sw=4 et:
37442d52 190 */