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 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 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