summaryrefslogtreecommitdiff
path: root/taint.c
blob: f1f6b7b73d8728bc062dadf88241eb4898b59b5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/*    taint.c
 *
 *    Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
 *    2002, 2003, 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

/*
 * '...we will have peace, when you and all your works have perished--and
 *  the works of your dark master to whom you would deliver us.  You are a
 *  liar, Saruman, and a corrupter of men's hearts.'       --Théoden
 *
 *     [p.580 of _The Lord of the Rings_, III/x: "The Voice of Saruman"]
 */

/* This file contains a few functions for handling data tainting in Perl
 */

#include "EXTERN.h"
#define PERL_IN_TAINT_C
#include "perl.h"

void
Perl_taint_proper(pTHX_ const char *f, const char *const s)
{
#if defined(HAS_SETEUID) && defined(DEBUGGING)
    PERL_ARGS_ASSERT_TAINT_PROPER;

    {
	const Uid_t  uid = PerlProc_getuid();
	const Uid_t euid = PerlProc_geteuid();

#if Uid_t_sign == 1 /* uid_t is unsigned. */
	DEBUG_u(PerlIO_printf(Perl_debug_log,
                              "%s %d %" UVuf " %" UVuf "\n",
                              s, TAINT_get, (UV)uid, (UV)euid));
#else /* uid_t is signed (Uid_t_sign == -1), or don't know. */
	DEBUG_u(PerlIO_printf(Perl_debug_log,
                              "%s %d %" IVdf " %" IVdf "\n",
                              s, TAINT_get, (IV)uid, (IV)euid));
#endif
    }
#endif

    if (TAINT_get) {
	const char *ug;

	if (!f)
	    f = PL_no_security;
	if (PerlProc_getuid() != PerlProc_geteuid())
	    ug = " while running setuid";
	else if (PerlProc_getgid() != PerlProc_getegid())
	    ug = " while running setgid";
	else if (TAINT_WARN_get)
            ug = " while running with -t switch";
        else
	    ug = " while running with -T switch";

        /* XXX because taint_proper adds extra format args, we can't
         * get the caller to check properly; o we just silence the warning
         * and hope the callers aren't naughty */
        GCC_DIAG_IGNORE(-Wformat-nonliteral);
	if (PL_unsafe || TAINT_WARN_get) {
	    Perl_ck_warner_d(aTHX_ packWARN(WARN_TAINT), f, s, ug);
        }
        else {
            Perl_croak(aTHX_ f, s, ug);
        }
        GCC_DIAG_RESTORE;

    }
}

void
Perl_taint_env(pTHX)
{
    SV** svp;
    MAGIC* mg;
    const char* const *e;
    static const char* const misc_env[] = {
	"IFS",		/* most shells' inter-field separators */
	"CDPATH",	/* ksh dain bramage #1 */
	"ENV",		/* ksh dain bramage #2 */
	"BASH_ENV",	/* bash dain bramage -- I guess it's contagious */
#ifdef WIN32
	"PERL5SHELL",	/* used for system() on Windows */
#endif
	NULL
    };

    /* Don't bother if there's no *ENV glob */
    if (!PL_envgv)
	return;
    /* If there's no %ENV hash or if it's not magical, croak, because
     * it probably doesn't reflect the actual environment */
    if (!GvHV(PL_envgv) || !(SvRMAGICAL(GvHV(PL_envgv))
	    && mg_find((const SV *)GvHV(PL_envgv), PERL_MAGIC_env))) {
	const bool was_tainted = TAINT_get;
	const char * const name = GvENAME(PL_envgv);
	TAINT;
	if (strEQ(name,"ENV"))
	    /* hash alias */
	    taint_proper("%%ENV is aliased to %s%s", "another variable");
	else
	    /* glob alias: report it in the error message */
	    taint_proper("%%ENV is aliased to %%%s%s", name);
	/* this statement is reached under -t or -U */
	TAINT_set(was_tainted);
#ifdef NO_TAINT_SUPPORT
        PERL_UNUSED_VAR(was_tainted);
#endif
    }

#ifdef VMS
    {
    int i = 0;
    char name[10 + TYPE_DIGITS(int)] = "DCL$PATH";
    STRLEN len = 8; /* strlen(name)  */

    while (1) {
	if (i)
	    len = my_sprintf(name,"DCL$PATH;%d", i);
	svp = hv_fetch(GvHVn(PL_envgv), name, len, FALSE);
	if (!svp || *svp == &PL_sv_undef)
	    break;
	if (SvTAINTED(*svp)) {
	    TAINT;
	    taint_proper("Insecure %s%s", "$ENV{DCL$PATH}");
	}
	if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
	    TAINT;
	    taint_proper("Insecure directory in %s%s", "$ENV{DCL$PATH}");
	}
	i++;
    }
  }
#endif /* VMS */

    svp = hv_fetchs(GvHVn(PL_envgv),"PATH",FALSE);
    if (svp && *svp) {
	if (SvTAINTED(*svp)) {
	    TAINT;
	    taint_proper("Insecure %s%s", "$ENV{PATH}");
	}
	if ((mg = mg_find(*svp, PERL_MAGIC_envelem)) && MgTAINTEDDIR(mg)) {
	    TAINT;
	    taint_proper("Insecure directory in %s%s", "$ENV{PATH}");
	}
    }

#ifndef VMS
    /* tainted $TERM is okay if it contains no metachars */
    svp = hv_fetchs(GvHVn(PL_envgv),"TERM",FALSE);
    if (svp && *svp && SvTAINTED(*svp)) {
	STRLEN len;
	const bool was_tainted = TAINT_get;
	const char *t = SvPV_const(*svp, len);
	const char * const e = t + len;

	TAINT_set(was_tainted);
#ifdef NO_TAINT_SUPPORT
        PERL_UNUSED_VAR(was_tainted);
#endif
	if (t < e && isWORDCHAR(*t))
	    t++;
	while (t < e && (isWORDCHAR(*t) || strchr("-_.+", *t)))
	    t++;
	if (t < e) {
	    TAINT;
	    taint_proper("Insecure $ENV{%s}%s", "TERM");
	}
    }
#endif /* !VMS */

    for (e = misc_env; *e; e++) {
	SV * const * const svp = hv_fetch(GvHVn(PL_envgv), *e, strlen(*e), FALSE);
	if (svp && *svp != &PL_sv_undef && SvTAINTED(*svp)) {
	    TAINT;
	    taint_proper("Insecure $ENV{%s}%s", *e);
	}
    }
}

/*
 * ex: set ts=8 sts=4 sw=4 et:
 */