1 /* taint.c
2 *
3 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
4 * 2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
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
11 /*
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
14 * liar, Saruman, and a corrupter of men's hearts.' --Théoden
15 *
16 * [p.580 of _The Lord of the Rings_, III/x: "The Voice of Saruman"]
17 */
18
19 /* This file contains a few functions for handling data tainting in Perl
20 */
21
22 #include "EXTERN.h"
23 #define PERL_IN_TAINT_C
24 #include "perl.h"
25
26 void
Perl_taint_proper(pTHX_ const char * f,const char * const s)27 Perl_taint_proper(pTHX_ const char *f, const char *const s)
28 {
29 /* Output a tainting violation, croaking unless we're just to warn.
30 * '_proper' is just to throw you off the scent */
31
32 #if defined(HAS_SETEUID) && defined(DEBUGGING)
33 PERL_ARGS_ASSERT_TAINT_PROPER;
34
35 {
36 const Uid_t uid = PerlProc_getuid();
37 const Uid_t euid = PerlProc_geteuid();
38
39 #if Uid_t_sign == 1 /* uid_t is unsigned. */
40 DEBUG_u(PerlIO_printf(Perl_debug_log,
41 "%s %d %" UVuf " %" UVuf "\n",
42 s, TAINT_get, (UV)uid, (UV)euid));
43 #else /* uid_t is signed (Uid_t_sign == -1), or don't know. */
44 DEBUG_u(PerlIO_printf(Perl_debug_log,
45 "%s %d %" IVdf " %" IVdf "\n",
46 s, TAINT_get, (IV)uid, (IV)euid));
47 #endif
48 }
49 #endif
50
51 if (TAINT_get) {
52 const char *ug;
53
54 if (!f)
55 f = PL_no_security;
56 if (PerlProc_getuid() != PerlProc_geteuid())
57 ug = " while running setuid";
58 else if (PerlProc_getgid() != PerlProc_getegid())
59 ug = " while running setgid";
60 else if (TAINT_WARN_get)
61 ug = " while running with -t switch";
62 else
63 ug = " while running with -T switch";
64
65 /* XXX because taint_proper adds extra format args, we can't
66 * get the caller to check properly; so we just silence the warning
67 * and hope the callers aren't naughty */
68 GCC_DIAG_IGNORE_STMT(-Wformat-nonliteral);
69 if (PL_unsafe || TAINT_WARN_get) {
70 Perl_ck_warner_d(aTHX_ packWARN(WARN_TAINT), f, s, ug);
71 }
72 else {
73 Perl_croak(aTHX_ f, s, ug);
74 }
75 GCC_DIAG_RESTORE_STMT;
76
77 }
78 }
79
80 void
Perl_taint_env(pTHX)81 Perl_taint_env(pTHX)
82 {
83 SV** svp;
84 const char* const *e;
85 static const char* const misc_env[] = {
86 "IFS", /* most shells' inter-field separators */
87 "CDPATH", /* ksh dain bramage #1 */
88 "ENV", /* ksh dain bramage #2 */
89 "BASH_ENV", /* bash dain bramage -- I guess it's contagious */
90 #ifdef WIN32
91 "PERL5SHELL", /* used for system() on Windows */
92 #endif
93 NULL
94 };
95
96 /* Don't bother if there's no *ENV glob */
97 if (!PL_envgv)
98 return;
99 /* If there's no %ENV hash or if it's not magical, croak, because
100 * it probably doesn't reflect the actual environment */
101 if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
102 && mg_find((const SV *)GvHV(PL_envgv), PERL_MAGIC_env))) {
103 const bool was_tainted = TAINT_get;
104 const char * const name = GvENAME(PL_envgv);
105 TAINT;
106 if (strEQ(name,"ENV"))
107 /* hash alias */
108 taint_proper("%%ENV is aliased to %s%s", "another variable");
109 else
110 /* glob alias: report it in the error message */
111 taint_proper("%%ENV is aliased to %%%s%s", name);
112 /* this statement is reached under -t or -U */
113 TAINT_set(was_tainted);
114 #ifdef NO_TAINT_SUPPORT
115 PERL_UNUSED_VAR(was_tainted);
116 #endif
117 }
118
119 #ifdef VMS
120 {
121 int i = 0;
122 char name[10 + TYPE_DIGITS(int)] = "DCL$PATH";
123 STRLEN len = 8; /* strlen(name) */
124
125 while (1) {
126 MAGIC* mg;
127 if (i)
128 len = my_snprintf(name, sizeof name, "DCL$PATH;%d", i);
129 svp = hv_fetch(GvHVn(PL_envgv), name, len, FALSE);
130 if (!svp || *svp == &PL_sv_undef)
131 break;
132 if (SvTAINTED(*svp)) {
133 TAINT;
134 taint_proper("Insecure %s%s", "$ENV{DCL$PATH}");
135 }
136 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
137 TAINT;
138 taint_proper("Insecure directory in %s%s", "$ENV{DCL$PATH}");
139 }
140 i++;
141 }
142 }
143 #endif /* VMS */
144
145 svp = hv_fetchs(GvHVn(PL_envgv),"PATH",FALSE);
146 if (svp && *svp) {
147 MAGIC* mg;
148 if (SvTAINTED(*svp)) {
149 TAINT;
150 taint_proper("Insecure %s%s", "$ENV{PATH}");
151 }
152 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
153 TAINT;
154 taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
155 }
156 }
157
158 #ifndef VMS
159 /* tainted $TERM is okay if it contains no metachars */
160 svp = hv_fetchs(GvHVn(PL_envgv),"TERM",FALSE);
161 if (svp && *svp && SvTAINTED(*svp)) {
162 STRLEN len;
163 const bool was_tainted = TAINT_get;
164 const char *t = SvPV_const(*svp, len);
165 const char * const e = t + len;
166
167 TAINT_set(was_tainted);
168 #ifdef NO_TAINT_SUPPORT
169 PERL_UNUSED_VAR(was_tainted);
170 #endif
171 if (t < e && isWORDCHAR(*t))
172 t++;
173 while (t < e && (isWORDCHAR(*t) || memCHRs("-_.+", *t)))
174 t++;
175 if (t < e) {
176 TAINT;
177 taint_proper("Insecure $ENV{%s}%s", "TERM");
178 }
179 }
180 #endif /* !VMS */
181
182 for (e = misc_env; *e; e++) {
183 SV * const * const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
184 if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
185 TAINT;
186 taint_proper("Insecure $ENV{%s}%s", *e);
187 }
188 }
189 }
190
191 /*
192 * ex: set ts=8 sts=4 sw=4 et:
193 */
194