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 /*
27 =for apidoc taint_proper
28
29 Implements the L</TAINT_PROPER> macro, which you should generally use instead.
30
31 =cut
32 */
33
34 void
Perl_taint_proper(pTHX_ const char * f,const char * const s)35 Perl_taint_proper(pTHX_ const char *f, const char *const s)
36 {
37 /* Don't use directly; instead use TAINT_PROPER
38 *
39 * Output a tainting violation, croaking unless we're just to warn.
40 * '_proper' is just to throw you off the scent */
41
42 #if defined(HAS_SETEUID) && defined(DEBUGGING)
43 PERL_ARGS_ASSERT_TAINT_PROPER;
44
45 {
46 const Uid_t uid = PerlProc_getuid();
47 const Uid_t euid = PerlProc_geteuid();
48
49 #if Uid_t_sign == 1 /* uid_t is unsigned. */
50 DEBUG_u(PerlIO_printf(Perl_debug_log,
51 "%s %d %" UVuf " %" UVuf "\n",
52 s, TAINT_get, (UV)uid, (UV)euid));
53 #else /* uid_t is signed (Uid_t_sign == -1), or don't know. */
54 DEBUG_u(PerlIO_printf(Perl_debug_log,
55 "%s %d %" IVdf " %" IVdf "\n",
56 s, TAINT_get, (IV)uid, (IV)euid));
57 #endif
58 }
59 #endif
60
61 if (TAINT_get) {
62 const char *ug;
63
64 if (!f)
65 f = PL_no_security;
66 if (PerlProc_getuid() != PerlProc_geteuid())
67 ug = " while running setuid";
68 else if (PerlProc_getgid() != PerlProc_getegid())
69 ug = " while running setgid";
70 else if (TAINT_WARN_get)
71 ug = " while running with -t switch";
72 else
73 ug = " while running with -T switch";
74
75 /* XXX because taint_proper adds extra format args, we can't
76 * get the caller to check properly; so we just silence the warning
77 * and hope the callers aren't naughty */
78 GCC_DIAG_IGNORE_STMT(-Wformat-nonliteral);
79 if (PL_unsafe || TAINT_WARN_get) {
80 Perl_ck_warner_d(aTHX_ packWARN(WARN_TAINT), f, s, ug);
81 }
82 else {
83 Perl_croak(aTHX_ f, s, ug);
84 }
85 GCC_DIAG_RESTORE_STMT;
86
87 }
88 }
89
90 /*
91 =for apidoc taint_env
92
93 Implements the L</TAINT_ENV> macro, which you should generally use instead.
94
95 =cut
96 */
97 void
Perl_taint_env(pTHX)98 Perl_taint_env(pTHX)
99 {
100 /* Don't use directly; instead use TAINT_ENV */
101
102 SV** svp;
103 const char* const *e;
104 static const char* const misc_env[] = {
105 "IFS", /* most shells' inter-field separators */
106 "CDPATH", /* ksh dain bramage #1 */
107 "ENV", /* ksh dain bramage #2 */
108 "BASH_ENV", /* bash dain bramage -- I guess it's contagious */
109 #ifdef WIN32
110 "PERL5SHELL", /* used for system() on Windows */
111 #endif
112 NULL
113 };
114
115 /* Don't bother if there's no *ENV glob */
116 if (!PL_envgv)
117 return;
118 /* If there's no %ENV hash or if it's not magical, croak, because
119 * it probably doesn't reflect the actual environment */
120 if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
121 && mg_find((const SV *)GvHV(PL_envgv), PERL_MAGIC_env))) {
122 const bool was_tainted = TAINT_get;
123 const char * const name = GvENAME(PL_envgv);
124 TAINT;
125 if (strEQ(name,"ENV"))
126 /* hash alias */
127 taint_proper("%%ENV is aliased to %s%s", "another variable");
128 else
129 /* glob alias: report it in the error message */
130 taint_proper("%%ENV is aliased to %%%s%s", name);
131 /* this statement is reached under -t or -U */
132 TAINT_set(was_tainted);
133 #ifdef NO_TAINT_SUPPORT
134 PERL_UNUSED_VAR(was_tainted);
135 #endif
136 }
137
138 #ifdef VMS
139 {
140 int i = 0;
141 char name[10 + TYPE_DIGITS(int)] = "DCL$PATH";
142 STRLEN len = 8; /* strlen(name) */
143
144 while (1) {
145 MAGIC* mg;
146 if (i)
147 len = my_snprintf(name, sizeof name, "DCL$PATH;%d", i);
148 svp = hv_fetch(GvHVn(PL_envgv), name, len, FALSE);
149 if (!svp || *svp == &PL_sv_undef)
150 break;
151 if (SvTAINTED(*svp)) {
152 TAINT;
153 taint_proper("Insecure %s%s", "$ENV{DCL$PATH}");
154 }
155 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
156 TAINT;
157 taint_proper("Insecure directory in %s%s", "$ENV{DCL$PATH}");
158 }
159 i++;
160 }
161 }
162 #endif /* VMS */
163
164 svp = hv_fetchs(GvHVn(PL_envgv),"PATH",FALSE);
165 if (svp && *svp) {
166 MAGIC* mg;
167 if (SvTAINTED(*svp)) {
168 TAINT;
169 taint_proper("Insecure %s%s", "$ENV{PATH}");
170 }
171 if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
172 TAINT;
173 taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
174 }
175 }
176
177 #ifndef VMS
178 /* tainted $TERM is okay if it contains no metachars */
179 svp = hv_fetchs(GvHVn(PL_envgv),"TERM",FALSE);
180 if (svp && *svp && SvTAINTED(*svp)) {
181 STRLEN len;
182 const bool was_tainted = TAINT_get;
183 const char *t = SvPV_const(*svp, len);
184 const char * const e = t + len;
185
186 TAINT_set(was_tainted);
187 #ifdef NO_TAINT_SUPPORT
188 PERL_UNUSED_VAR(was_tainted);
189 #endif
190 if (t < e && isWORDCHAR(*t))
191 t++;
192 while (t < e && (isWORDCHAR(*t) || memCHRs("-_.+", *t)))
193 t++;
194 if (t < e) {
195 TAINT;
196 taint_proper("Insecure $ENV{%s}%s", "TERM");
197 }
198 }
199 #endif /* !VMS */
200
201 for (e = misc_env; *e; e++) {
202 SV * const * const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
203 if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
204 TAINT;
205 taint_proper("Insecure $ENV{%s}%s", *e);
206 }
207 }
208 }
209
210 /*
211 * ex: set ts=8 sts=4 sw=4 et:
212 */
213