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