xref: /openbsd-src/gnu/usr.bin/perl/taint.c (revision 850e275390052b330d93020bf619a739a3c277ac)
1 /*    taint.c
2  *
3  *    Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 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."  --Theoden
15  */
16 
17 /* This file contains a few functions for handling data tainting in Perl
18  */
19 
20 #include "EXTERN.h"
21 #define PERL_IN_TAINT_C
22 #include "perl.h"
23 
24 void
25 Perl_taint_proper(pTHX_ const char *f, const char *s)
26 {
27 #if defined(HAS_SETEUID) && defined(DEBUGGING)
28 #   if Uid_t_size == 1
29     {
30 	const UV  uid = PL_uid;
31 	const UV euid = PL_euid;
32 
33 	DEBUG_u(PerlIO_printf(Perl_debug_log,
34 			       "%s %d %"UVuf" %"UVuf"\n",
35 			       s, PL_tainted, uid, euid));
36     }
37 #   else
38     {
39 	const IV  uid = PL_uid;
40 	const IV euid = PL_euid;
41 
42 	DEBUG_u(PerlIO_printf(Perl_debug_log,
43 			       "%s %d %"IVdf" %"IVdf"\n",
44 			       s, PL_tainted, uid, euid));
45     }
46 #   endif
47 #endif
48 
49     if (PL_tainted) {
50 	const char *ug;
51 
52 	if (!f)
53 	    f = PL_no_security;
54 	if (PL_euid != PL_uid)
55 	    ug = " while running setuid";
56 	else if (PL_egid != PL_gid)
57 	    ug = " while running setgid";
58 	else if (PL_taint_warn)
59             ug = " while running with -t switch";
60         else
61 	    ug = " while running with -T switch";
62 	if (PL_unsafe || PL_taint_warn) {
63             if(ckWARN(WARN_TAINT))
64                 Perl_warner(aTHX_ packWARN(WARN_TAINT), f, s, ug);
65         }
66         else {
67             Perl_croak(aTHX_ f, s, ug);
68         }
69     }
70 }
71 
72 void
73 Perl_taint_env(pTHX)
74 {
75     SV** svp;
76     MAGIC* mg;
77     const char* const *e;
78     static const char* const misc_env[] = {
79 	"IFS",		/* most shells' inter-field separators */
80 	"CDPATH",	/* ksh dain bramage #1 */
81 	"ENV",		/* ksh dain bramage #2 */
82 	"BASH_ENV",	/* bash dain bramage -- I guess it's contagious */
83 	NULL
84     };
85 
86     /* Don't bother if there's no *ENV glob */
87     if (!PL_envgv)
88 	return;
89     /* If there's no %ENV hash of if it's not magical, croak, because
90      * it probably doesn't reflect the actual environment */
91     if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
92 	    && mg_find((SV*)GvHV(PL_envgv), PERL_MAGIC_env))) {
93 	const bool was_tainted = PL_tainted;
94 	const char * const name = GvENAME(PL_envgv);
95 	PL_tainted = TRUE;
96 	if (strEQ(name,"ENV"))
97 	    /* hash alias */
98 	    taint_proper("%%ENV is aliased to %s%s", "another variable");
99 	else
100 	    /* glob alias: report it in the error message */
101 	    taint_proper("%%ENV is aliased to %%%s%s", name);
102 	/* this statement is reached under -t or -U */
103 	PL_tainted = was_tainted;
104     }
105 
106 #ifdef VMS
107     {
108     int i = 0;
109     char name[10 + TYPE_DIGITS(int)] = "DCL$PATH";
110 
111     while (1) {
112 	if (i)
113 	    (void)sprintf(name,"DCL$PATH;%d", i);
114 	svp = hv_fetch(GvHVn(PL_envgv), name, strlen(name), FALSE);
115 	if (!svp || *svp == &PL_sv_undef)
116 	    break;
117 	if (SvTAINTED(*svp)) {
118 	    TAINT;
119 	    taint_proper("Insecure %s%s", "$ENV{DCL$PATH}");
120 	}
121 	if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
122 	    TAINT;
123 	    taint_proper("Insecure directory in %s%s", "$ENV{DCL$PATH}");
124 	}
125 	i++;
126     }
127   }
128 #endif /* VMS */
129 
130     svp = hv_fetch(GvHVn(PL_envgv),"PATH",4,FALSE);
131     if (svp && *svp) {
132 	if (SvTAINTED(*svp)) {
133 	    TAINT;
134 	    taint_proper("Insecure %s%s", "$ENV{PATH}");
135 	}
136 	if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
137 	    TAINT;
138 	    taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
139 	}
140     }
141 
142 #ifndef VMS
143     /* tainted $TERM is okay if it contains no metachars */
144     svp = hv_fetch(GvHVn(PL_envgv),"TERM",4,FALSE);
145     if (svp && *svp && SvTAINTED(*svp)) {
146 	STRLEN len;
147 	const bool was_tainted = PL_tainted;
148 	const char *t = SvPV_const(*svp, len);
149 	const char * const e = t + len;
150 	PL_tainted = was_tainted;
151 	if (t < e && isALNUM(*t))
152 	    t++;
153 	while (t < e && (isALNUM(*t) || strchr("-_.+", *t)))
154 	    t++;
155 	if (t < e) {
156 	    TAINT;
157 	    taint_proper("Insecure $ENV{%s}%s", "TERM");
158 	}
159     }
160 #endif /* !VMS */
161 
162     for (e = misc_env; *e; e++) {
163 	SV ** const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
164 	if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
165 	    TAINT;
166 	    taint_proper("Insecure $ENV{%s}%s", *e);
167 	}
168     }
169 }
170 
171 /*
172  * Local variables:
173  * c-indentation-style: bsd
174  * c-basic-offset: 4
175  * indent-tabs-mode: t
176  * End:
177  *
178  * ex: set ts=8 sts=4 sw=4 noet:
179  */
180