X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/a783c5f421048120dc022238eeb6eb8a62d130d0..178eb895c5deb67bb37c347449d4e8f3288b8b7e:/perl.c diff --git a/perl.c b/perl.c index bfe3ccc..63438e8 100644 --- a/perl.c +++ b/perl.c @@ -1,7 +1,7 @@ /* perl.c * * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, - * 2000, 2001, 2002, 2003, by Larry Wall and others + * 2000, 2001, 2002, 2003, 2004, 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. @@ -12,6 +12,65 @@ * "A ship then new they built for him/of mithril and of elven glass" --Bilbo */ +/* PSz 12 Nov 03 + * + * Be proud that perl(1) may proclaim: + * Setuid Perl scripts are safer than C programs ... + * Do not abandon (deprecate) suidperl. Do not advocate C wrappers. + * + * The flow was: perl starts, notices script is suid, execs suidperl with same + * arguments; suidperl opens script, checks many things, sets itself with + * right UID, execs perl with similar arguments but with script pre-opened on + * /dev/fd/xxx; perl checks script is as should be and does work. This was + * insecure: see perlsec(1) for many problems with this approach. + * + * The "correct" flow should be: perl starts, opens script and notices it is + * suid, checks many things, execs suidperl with similar arguments but with + * script on /dev/fd/xxx; suidperl checks script and /dev/fd/xxx object are + * same, checks arguments match #! line, sets itself with right UID, execs + * perl with same arguments; perl checks many things and does work. + * + * (Opening the script in perl instead of suidperl, we "lose" scripts that + * are readable to the target UID but not to the invoker. Where did + * unreadable scripts work anyway?) + * + * For now, suidperl and perl are pretty much the same large and cumbersome + * program, so suidperl can check its argument list (see comments elsewhere). + * + * References: + * Original bug report: + * http://bugs.perl.org/index.html?req=bug_id&bug_id=20010322.218 + * http://rt.perl.org/rt2/Ticket/Display.html?id=6511 + * Comments and discussion with Debian: + * http://bugs.debian.org/203426 + * http://bugs.debian.org/220486 + * Debian Security Advisory DSA 431-1 (does not fully fix problem): + * http://www.debian.org/security/2004/dsa-431 + * CVE candidate: + * http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0618 + * Previous versions of this patch sent to perl5-porters: + * http://www.mail-archive.com/perl5-porters@perl.org/msg71953.html + * http://www.mail-archive.com/perl5-porters@perl.org/msg75245.html + * http://www.mail-archive.com/perl5-porters@perl.org/msg75563.html + * http://www.mail-archive.com/perl5-porters@perl.org/msg75635.html + * +Paul Szabo - psz@maths.usyd.edu.au http://www.maths.usyd.edu.au:8000/u/psz/ +School of Mathematics and Statistics University of Sydney 2006 Australia + * + */ +/* PSz 13 Nov 03 + * Use truthful, neat, specific error messages. + * Cannot always hide the truth; security must not depend on doing so. + */ + +/* PSz 18 Feb 04 + * Use global(?), thread-local fdscript for easier checks. + * (I do not understand how we could possibly get a thread race: + * do not all threads go through the same initialization? Or in + * fact, are not threads started only after we get the script and + * so know what to do? Oh well, make things super-safe...) + */ + #include "EXTERN.h" #define PERL_IN_PERL_C #include "perl.h" @@ -49,7 +108,7 @@ static I32 read_e_script(pTHX_ int idx, SV *buf_sv, int maxlen); #ifndef DOSUID #define DOSUID #endif -#endif +#endif /* IAMSUID */ #ifdef SETUID_SCRIPTS_ARE_SECURE_NOW #ifdef DOSUID @@ -181,6 +240,9 @@ perl_construct(pTHXx) SvNV(&PL_sv_yes); SvREADONLY_on(&PL_sv_yes); SvREFCNT(&PL_sv_yes) = (~(U32)0)/2; + + SvREADONLY_on(&PL_sv_placeholder); + SvREFCNT(&PL_sv_placeholder) = (~(U32)0)/2; } PL_sighandlerp = Perl_sighandler; @@ -260,8 +322,10 @@ perl_construct(pTHXx) ("__environ", (unsigned long *) &environ_pointer, NULL); #endif /* environ */ -#ifdef USE_ENVIRON_ARRAY +#ifndef PERL_MICRO +# ifdef USE_ENVIRON_ARRAY PL_origenviron = environ; +# endif #endif /* Use sysconf(_SC_CLK_TCK) if available, if not @@ -349,6 +413,10 @@ perl_destruct(pTHXx) /* Destroy the main CV and syntax tree */ if (PL_main_root) { + /* ensure comppad/curpad to refer to main's pad */ + if (CvPADLIST(PL_main_cv)) { + PAD_SET_CUR_NOSAVE(CvPADLIST(PL_main_cv), 1); + } op_free(PL_main_root); PL_main_root = Nullop; } @@ -372,6 +440,7 @@ perl_destruct(pTHXx) * Non-referenced objects are on their own. */ sv_clean_objs(); + PL_sv_objcount = 0; } /* unhook hooks which will soon be, or use, destroyed data */ @@ -406,6 +475,7 @@ perl_destruct(pTHXx) /* if PERL_USE_SAFE_PUTENV is defined environ will not have been copied * so we certainly shouldn't free it here */ +#ifndef PERL_MICRO #if defined(USE_ENVIRON_ARRAY) && !defined(PERL_USE_SAFE_PUTENV) if (environ != PL_origenviron #ifdef USE_ITHREADS @@ -425,6 +495,7 @@ perl_destruct(pTHXx) environ = PL_origenviron; } #endif +#endif /* !PERL_MICRO */ #ifdef USE_ITHREADS /* the syntax tree is shared between clones @@ -495,6 +566,8 @@ perl_destruct(pTHXx) PL_e_script = Nullsv; } + PL_perldb = 0; + /* magical thingies */ SvREFCNT_dec(PL_ofs_sv); /* $, */ @@ -554,6 +627,15 @@ perl_destruct(pTHXx) PL_stderrgv = Nullgv; PL_last_in_gv = Nullgv; PL_replgv = Nullgv; + PL_DBgv = Nullgv; + PL_DBline = Nullgv; + PL_DBsub = Nullgv; + PL_DBsingle = Nullsv; + PL_DBtrace = Nullsv; + PL_DBsignal = Nullsv; + PL_DBassertion = Nullsv; + PL_DBcv = Nullcv; + PL_dbargs = Nullav; PL_debstash = Nullhv; /* reset so print() ends up where we expect */ @@ -588,6 +670,7 @@ perl_destruct(pTHXx) Safefree(PL_numeric_name); PL_numeric_name = Nullch; SvREFCNT_dec(PL_numeric_radix_sv); + PL_numeric_radix_sv = Nullsv; #endif /* clear utf8 character classes */ @@ -726,6 +809,7 @@ perl_destruct(pTHXx) #ifdef USE_ITHREADS /* free the pointer table used for cloning */ ptr_table_free(PL_ptr_table); + PL_ptr_table = (PTR_TBL_t*)NULL; #endif /* free special SVs */ @@ -763,12 +847,15 @@ perl_destruct(pTHXx) svend = &sva[SvREFCNT(sva)]; for (sv = sva + 1; sv < svend; ++sv) { if (SvTYPE(sv) != SVTYPEMASK) { - PerlIO_printf(Perl_debug_log, "leaked: 0x%p\n", sv); + PerlIO_printf(Perl_debug_log, "leaked: 0x%p" + pTHX__FORMAT "\n", + sv pTHX__VALUE); } } } } #endif + PL_sv_count = 0; #if defined(PERLIO_LAYERS) @@ -784,18 +871,31 @@ perl_destruct(pTHXx) SvREADONLY_off(&PL_sv_undef); Safefree(PL_origfilename); + PL_origfilename = Nullch; Safefree(PL_reg_start_tmp); + PL_reg_start_tmp = (char**)NULL; + PL_reg_start_tmpl = 0; if (PL_reg_curpm) Safefree(PL_reg_curpm); Safefree(PL_reg_poscache); free_tied_hv_pool(); Safefree(PL_op_mask); Safefree(PL_psig_ptr); + PL_psig_ptr = (SV**)NULL; Safefree(PL_psig_name); + PL_psig_name = (SV**)NULL; Safefree(PL_bitcount); + PL_bitcount = Nullch; Safefree(PL_psig_pend); + PL_psig_pend = (int*)NULL; + PL_formfeed = Nullsv; + Safefree(PL_ofmt); + PL_ofmt = Nullch; nuke_stacks(); + PL_tainting = FALSE; + PL_taint_warn = FALSE; PL_hints = 0; /* Reset hints. Should hints be per-interpreter ? */ + PL_debug = 0; DEBUG_P(debprofdump()); @@ -894,16 +994,17 @@ perl_parse(pTHXx_ XSINIT_t xsinit, int argc, char **argv, char **env) #undef IAMSUID Perl_croak(aTHX_ "suidperl is no longer needed since the kernel can now execute\n\ setuid perl scripts securely.\n"); -#endif +#endif /* IAMSUID */ #endif #if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) /* [perl #22371] Algorimic Complexity Attack on Perl 5.6.1, 5.8.0 * This MUST be done before any hash stores or fetches take place. - * If you set PL_hash_seed (and assumedly also PL_hash_seed_set) yourself, - * it is your responsibility to provide a good random seed! */ - if (!PL_hash_seed_set) - PL_hash_seed = get_hash_seed(); + * If you set PL_rehash_seed (and assumedly also PL_rehash_seed_set) + * yourself, it is your responsibility to provide a good random seed! + * You can also define PERL_HASH_SEED in compile time, see hv.h. */ + if (!PL_rehash_seed_set) + PL_rehash_seed = get_hash_seed(); { char *s = PerlEnv_getenv("PERL_HASH_SEED_DEBUG"); @@ -912,7 +1013,7 @@ setuid perl scripts securely.\n"); if (i == 1) PerlIO_printf(Perl_debug_log, "HASH_SEED = %"UVuf"\n", - PL_hash_seed); + PL_rehash_seed); } } #endif /* #if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) */ @@ -923,12 +1024,12 @@ setuid perl scripts securely.\n"); { /* Set PL_origalen be the sum of the contiguous argv[] * elements plus the size of the env in case that it is - * contiguous with the argv[]. This is used in mg.c:mg_set() + * contiguous with the argv[]. This is used in mg.c:Perl_magic_set() * as the maximum modifiable length of $0. In the worst case * the area we are able to modify is limited to the size of * the original argv[0]. (See below for 'contiguous', though.) * --jhi */ - char *s; + char *s = NULL; int i; UV mask = ~(UV)(PTRSIZE == 4 ? 3 : PTRSIZE == 8 ? 7 : PTRSIZE == 16 ? 15 : 0); @@ -945,26 +1046,27 @@ setuid perl scripts securely.\n"); * PTRSIZE bytes. As long as no system has something bizarre * like the argv[] interleaved with some other data, we are * fine. (Did I just evoke Murphy's Law?) --jhi */ - s = PL_origargv[0]; - while (*s) s++; - for (i = 1; i < PL_origargc; i++) { - if ((PL_origargv[i] == s + 1 + if (PL_origargv && PL_origargc >= 1 && (s = PL_origargv[0])) { + while (*s) s++; + for (i = 1; i < PL_origargc; i++) { + if ((PL_origargv[i] == s + 1 #ifdef OS2 - || PL_origargv[i] == s + 2 + || PL_origargv[i] == s + 2 #endif - ) - || - (aligned && - (PL_origargv[i] > s && - PL_origargv[i] <= - INT2PTR(char *, PTR2UV(s + PTRSIZE) & mask))) - ) - { - s = PL_origargv[i]; - while (*s) s++; + ) + || + (aligned && + (PL_origargv[i] > s && + PL_origargv[i] <= + INT2PTR(char *, PTR2UV(s + PTRSIZE) & mask))) + ) + { + s = PL_origargv[i]; + while (*s) s++; + } + else + break; } - else - break; } /* Can we grab env area too to be used as the area for $0? */ if (PL_origenviron) { @@ -1003,7 +1105,7 @@ setuid perl scripts securely.\n"); } } } - PL_origalen = s - PL_origargv[0]; + PL_origalen = s - PL_origargv[0] + 1; } if (PL_do_undump) { @@ -1083,13 +1185,14 @@ S_parse_body(pTHX_ char **env, XSINIT_t xsinit) int argc = PL_origargc; char **argv = PL_origargv; char *scriptname = NULL; - int fdscript = -1; VOL bool dosearch = FALSE; char *validarg = ""; register SV *sv; register char *s; char *cddir = Nullch; + PL_fdscript = -1; + PL_suidscript = -1; sv_setpvn(PL_linestr,"",0); sv = newSVpvn("",0); /* first used for -I flags */ SAVEFREESV(sv); @@ -1103,6 +1206,12 @@ S_parse_body(pTHX_ char **env, XSINIT_t xsinit) validarg = " PHOOEY "; else validarg = argv[0]; + /* + * Can we rely on the kernel to start scripts with argv[1] set to + * contain all #! line switches (the whole line)? (argv[0] is set to + * the interpreter name, argv[2] to the script name; argv[3] and + * above may contain other arguments.) + */ #endif s = argv[0]+1; reswitch: @@ -1158,8 +1267,7 @@ S_parse_body(pTHX_ char **env, XSINIT_t xsinit) if (argv[1] && !strcmp(argv[1], "Dev:Pseudo")) break; #endif - if (PL_euid != PL_uid || PL_egid != PL_gid) - Perl_croak(aTHX_ "No -e allowed in setuid scripts"); + forbid_setid("-e"); if (!PL_e_script) { PL_e_script = newSVpvn("",0); filter_add(read_e_script, NULL); @@ -1317,7 +1425,6 @@ print \" \\@INC:\\n @INC\\n\";"); } } switch_end: - sv_setsv(get_sv("/", TRUE), PL_rs); if ( #ifndef SECURE_INTERNAL_GETENV @@ -1392,9 +1499,9 @@ print \" \\@INC:\\n @INC\\n\";"); init_perllib(); - open_script(scriptname,dosearch,sv,&fdscript); + open_script(scriptname,dosearch,sv); - validate_suid(validarg, scriptname,fdscript); + validate_suid(validarg, scriptname); #ifndef PERL_MICRO #if defined(SIGCHLD) || defined(SIGCLD) @@ -1437,9 +1544,7 @@ print \" \\@INC:\\n @INC\\n\";"); boot_core_PerlIO(); boot_core_UNIVERSAL(); -#ifndef PERL_MICRO boot_core_xsutils(); -#endif if (xsinit) (*xsinit)(aTHX); /* in case linked C routines want magical variables */ @@ -1657,7 +1762,8 @@ S_run_body(pTHX_ I32 oldscope) if (!PL_restartop) { DEBUG_x(dump_all()); - DEBUG(PerlIO_printf(Perl_debug_log, "\nEXECUTING...\n\n")); + if (!DEBUG_q_TEST) + PERL_DEBUG(PerlIO_printf(Perl_debug_log, "\nEXECUTING...\n\n")); DEBUG_S(PerlIO_printf(Perl_debug_log, "main thread is 0x%"UVxf"\n", PTR2UV(thr))); @@ -2232,11 +2338,11 @@ S_usage(pTHX_ char *name) /* XXX move this out into a module ? */ static char *usage_msg[] = { "-0[octal] specify record separator (\\0, if no argument)", "-a autosplit mode with -n or -p (splits $_ into @F)", -"-C enable native wide character system interfaces", +"-C[number/list] enables the listed Unicode features", "-c check syntax only (runs BEGIN and CHECK blocks)", "-d[:debugger] run program under debugger", "-D[number/list] set debugging flags (argument is a bit mask or alphabets)", -"-e 'command' one line of program (several -e's allowed, omit programfile)", +"-e program one line of program (several -e's allowed, omit programfile)", "-F/pattern/ split() pattern for -a switch (//'s are optional)", "-i[extension] edit <> files in place (makes backup if extension supplied)", "-Idirectory specify @INC/#include directory (several -I's allowed)", @@ -2247,16 +2353,16 @@ S_usage(pTHX_ char *name) /* XXX move this out into a module ? */ "-P run program through C preprocessor before compilation", "-s enable rudimentary parsing for switches after programfile", "-S look for programfile using PATH environment variable", -"-T enable tainting checks", "-t enable tainting warnings", +"-T enable tainting checks", "-u dump core after parsing program", "-U allow unsafe operations", "-v print version, subversion (includes VERY IMPORTANT perl info)", "-V[:variable] print configuration summary (or a single Config.pm variable)", "-w enable many useful warnings (RECOMMENDED)", "-W enable all warnings", -"-X disable all warnings", "-x[directory] strip off text before #!perl line and perhaps cd to directory", +"-X disable all warnings", "\n", NULL }; @@ -2279,7 +2385,7 @@ Perl_get_debug_opts(pTHX_ char **s) int i = 0; if (isALPHA(**s)) { /* if adding extra options, remember to update DEBUG_MASK */ - static char debopts[] = "psltocPmfrxu HXDSTRJvC"; + static char debopts[] = "psltocPmfrxu HXDSTRJvCAq"; for (; isALNUM(**s); (*s)++) { char *d = strchr(debopts,**s); @@ -2349,6 +2455,7 @@ Perl_moreswitches(pTHX_ char *s) PL_rs = newSVpvn(&ch, 1); } } + sv_setsv(get_sv("/", TRUE), PL_rs); return s + numlen; } case 'C': @@ -2388,7 +2495,7 @@ Perl_moreswitches(pTHX_ char *s) sv_catpvn(sv, start, s-start); sv_catpv(sv, " split(/,/,q{"); sv_catpv(sv, ++s); - sv_catpv(sv, "})"); + sv_catpv(sv, "})"); } s += strlen(s); my_setenv("PERL5DB", SvPV(sv, PL_na)); @@ -2487,9 +2594,10 @@ Perl_moreswitches(pTHX_ char *s) if (!PL_preambleav) PL_preambleav = newAV(); if (*++s) { - SV *sv = newSVpvn("use assertions::activate split(/,/,q{",37); + SV *sv = newSVpv("use assertions::activate split(/,/,q", 0); + sv_catpvn(sv, "\0", 1); /* Use NUL as q//-delimiter. */ sv_catpv(sv,s); - sv_catpv(sv,"})"); + sv_catpvn(sv, "\0)", 2); s+=strlen(s); av_push(PL_preambleav, sv); } @@ -2523,9 +2631,10 @@ Perl_moreswitches(pTHX_ char *s) Perl_croak(aTHX_ "Module name required with -%c option", s[-1]); sv_catpvn(sv, start, s-start); - sv_catpv(sv, " split(/,/,q{"); + sv_catpv(sv, " split(/,/,q"); + sv_catpvn(sv, "\0)", 1); /* Use NUL as q//-delimiter. */ sv_catpv(sv, ++s); - sv_catpv(sv, "})"); + sv_catpvn(sv, "\0)", 2); } s += strlen(s); if (!PL_preambleav) @@ -2596,7 +2705,7 @@ Perl_moreswitches(pTHX_ char *s) #endif PerlIO_printf(PerlIO_stdout(), - "\n\nCopyright 1987-2003, Larry Wall\n"); + "\n\nCopyright 1987-2004, Larry Wall\n"); #ifdef MACOS_TRADITIONAL PerlIO_printf(PerlIO_stdout(), "\nMac OS port Copyright 1991-2002, Matthias Neeracher;\n" @@ -2823,15 +2932,19 @@ S_init_main_stash(pTHX) sv_setpvn(get_sv("/", TRUE), "\n", 1); } +/* PSz 18 Nov 03 fdscript now global but do not change prototype */ STATIC void -S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) +S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv) { +#ifndef IAMSUID char *quote; char *code; char *cpp_discard_flag; char *perl; +#endif - *fdscript = -1; + PL_fdscript = -1; + PL_suidscript = -1; if (PL_e_script) { PL_origfilename = savepv("-e"); @@ -2842,10 +2955,30 @@ S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) if (strnEQ(scriptname, "/dev/fd/", 8) && isDIGIT(scriptname[8]) ) { char *s = scriptname + 8; - *fdscript = atoi(s); + PL_fdscript = atoi(s); while (isDIGIT(*s)) s++; if (*s) { + /* PSz 18 Feb 04 + * Tell apart "normal" usage of fdscript, e.g. + * with bash on FreeBSD: + * perl <( echo '#!perl -DA'; echo 'print "$0\n"') + * from usage in suidperl. + * Does any "normal" usage leave garbage after the number??? + * Is it a mistake to use a similar /dev/fd/ construct for + * suidperl? + */ + PL_suidscript = 1; + /* PSz 20 Feb 04 + * Be supersafe and do some sanity-checks. + * Still, can we be sure we got the right thing? + */ + if (*s != '/') { + Perl_croak(aTHX_ "Wrong syntax (suid) fd script name \"%s\"\n", s); + } + if (! *(s+1)) { + Perl_croak(aTHX_ "Missing (suid) fd script name\n"); + } scriptname = savepv(s + 1); Safefree(PL_origfilename); PL_origfilename = scriptname; @@ -2857,19 +2990,35 @@ S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) CopFILE_set(PL_curcop, PL_origfilename); if (strEQ(PL_origfilename,"-")) scriptname = ""; - if (*fdscript >= 0) { - PL_rsfp = PerlIO_fdopen(*fdscript,PERL_SCRIPT_MODE); + if (PL_fdscript >= 0) { + PL_rsfp = PerlIO_fdopen(PL_fdscript,PERL_SCRIPT_MODE); # if defined(HAS_FCNTL) && defined(F_SETFD) if (PL_rsfp) /* ensure close-on-exec */ fcntl(PerlIO_fileno(PL_rsfp),F_SETFD,1); # endif } +#ifdef IAMSUID + else { + Perl_croak(aTHX_ "suidperl needs fd script\n"); +/* PSz 11 Nov 03 + * Do not open (or do other fancy stuff) while setuid. + * Perl does the open, and hands script to suidperl on a fd; + * suidperl only does some checks, sets up UIDs and re-execs + * perl with that fd as it has always done. + */ + } + if (PL_suidscript != 1) { + Perl_croak(aTHX_ "suidperl needs (suid) fd script\n"); + } +#else /* IAMSUID */ else if (PL_preprocess) { char *cpp_cfg = CPPSTDIN; SV *cpp = newSVpvn("",0); SV *cmd = NEWSV(0,0); + if (cpp_cfg[0] == 0) /* PERL_MICRO? */ + Perl_croak(aTHX_ "Can't run with cpp -P with CPPSTDIN undefined"); if (strEQ(cpp_cfg, "cppstdin")) Perl_sv_catpvf(aTHX_ cpp, "%s/", BIN_EXP); sv_catpv(cpp, cpp_cfg); @@ -2919,25 +3068,6 @@ S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) cpp_discard_flag, sv, CPPMINUS); PL_doextract = FALSE; -# ifdef IAMSUID /* actually, this is caught earlier */ - if (PL_euid != PL_uid && !PL_euid) { /* if running suidperl */ -# ifdef HAS_SETEUID - (void)seteuid(PL_uid); /* musn't stay setuid root */ -# else -# ifdef HAS_SETREUID - (void)setreuid((Uid_t)-1, PL_uid); -# else -# ifdef HAS_SETRESUID - (void)setresuid((Uid_t)-1, PL_uid, (Uid_t)-1); -# else - PerlProc_setuid(PL_uid); -# endif -# endif -# endif - if (PerlProc_geteuid() != PL_uid) - Perl_croak(aTHX_ "Can't do seteuid!\n"); - } -# endif /* IAMSUID */ DEBUG_P(PerlIO_printf(Perl_debug_log, "PL_preprocess: cmd=\"%s\"\n", @@ -2959,32 +3089,11 @@ S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) fcntl(PerlIO_fileno(PL_rsfp),F_SETFD,1); # endif } +#endif /* IAMSUID */ if (!PL_rsfp) { -# ifdef DOSUID -# ifndef IAMSUID /* in case script is not readable before setuid */ - if (PL_euid && - PerlLIO_stat(CopFILE(PL_curcop),&PL_statbuf) >= 0 && - PL_statbuf.st_mode & (S_ISUID|S_ISGID)) - { - /* try again */ - PERL_FPU_PRE_EXEC - PerlProc_execv(Perl_form(aTHX_ "%s/sperl"PERL_FS_VER_FMT, - BIN_EXP, (int)PERL_REVISION, - (int)PERL_VERSION, - (int)PERL_SUBVERSION), PL_origargv); - PERL_FPU_POST_EXEC - Perl_croak(aTHX_ "Can't do setuid\n"); - } -# endif -# endif -# ifdef IAMSUID - errno = EPERM; - Perl_croak(aTHX_ "Can't open perl script: %s\n", - Strerror(errno)); -# else +/* PSz 16 Sep 03 Keep neat error message */ Perl_croak(aTHX_ "Can't open perl script \"%s\": %s\n", CopFILE(PL_curcop), Strerror(errno)); -# endif } } @@ -2999,8 +3108,19 @@ S_open_script(pTHX_ char *scriptname, bool dosearch, SV *sv, int *fdscript) STATIC int S_fd_on_nosuid_fs(pTHX_ int fd) { +/* PSz 27 Feb 04 + * We used to do this as "plain" user (after swapping UIDs with setreuid); + * but is needed also on machines without setreuid. + * Seems safe enough to run as root. + */ int check_okay = 0; /* able to do all the required sys/libcalls */ int on_nosuid = 0; /* the fd is on a nosuid fs */ + /* PSz 12 Nov 03 + * Need to check noexec also: nosuid might not be set, the average + * sysadmin would say that nosuid is irrelevant once he sets noexec. + */ + int on_noexec = 0; /* the fd is on a noexec fs */ + /* * Preferred order: fstatvfs(), fstatfs(), ustat()+getmnt(), getmntent(). * fstatvfs() is UNIX98. @@ -3019,10 +3139,16 @@ S_fd_on_nosuid_fs(pTHX_ int fd) check_okay = fstatvfs(fd, &stfs) == 0; on_nosuid = check_okay && (stfs.f_flag & ST_NOSUID); +#ifdef ST_NOEXEC + /* ST_NOEXEC certainly absent on AIX 5.1, and doesn't seem to be documented + on platforms where it is present. */ + on_noexec = check_okay && (stfs.f_flag & ST_NOEXEC); +#endif # endif /* fstatvfs */ # if !defined(FD_ON_NOSUID_CHECK_OKAY) && \ defined(PERL_MOUNT_NOSUID) && \ + defined(PERL_MOUNT_NOEXEC) && \ defined(HAS_FSTATFS) && \ defined(HAS_STRUCT_STATFS) && \ defined(HAS_STRUCT_STATFS_F_FLAGS) @@ -3031,10 +3157,12 @@ S_fd_on_nosuid_fs(pTHX_ int fd) check_okay = fstatfs(fd, &stfs) == 0; on_nosuid = check_okay && (stfs.f_flags & PERL_MOUNT_NOSUID); + on_noexec = check_okay && (stfs.f_flags & PERL_MOUNT_NOEXEC); # endif /* fstatfs */ # if !defined(FD_ON_NOSUID_CHECK_OKAY) && \ defined(PERL_MOUNT_NOSUID) && \ + defined(PERL_MOUNT_NOEXEC) && \ defined(HAS_FSTAT) && \ defined(HAS_USTAT) && \ defined(HAS_GETMNT) && \ @@ -3057,6 +3185,7 @@ S_fd_on_nosuid_fs(pTHX_ int fd) fdst.st_dev == fsd.fd_req.dev) { check_okay = 1; on_nosuid = fsd.fd_req.flags & PERL_MOUNT_NOSUID; + on_noexec = fsd.fd_req.flags & PERL_MOUNT_NOEXEC; } } } @@ -3067,7 +3196,8 @@ S_fd_on_nosuid_fs(pTHX_ int fd) # if !defined(FD_ON_NOSUID_CHECK_OKAY) && \ defined(HAS_GETMNTENT) && \ defined(HAS_HASMNTOPT) && \ - defined(MNTOPT_NOSUID) + defined(MNTOPT_NOSUID) && \ + defined(MNTOPT_NOEXEC) # define FD_ON_NOSUID_CHECK_OKAY FILE *mtab = fopen("/etc/mtab", "r"); struct mntent *entry; @@ -3082,6 +3212,8 @@ S_fd_on_nosuid_fs(pTHX_ int fd) check_okay = 1; if (hasmntopt(entry, MNTOPT_NOSUID)) on_nosuid = 1; + if (hasmntopt(entry, MNTOPT_NOEXEC)) + on_noexec = 1; break; } /* A single fs may well fail its stat(). */ } @@ -3091,17 +3223,21 @@ S_fd_on_nosuid_fs(pTHX_ int fd) # endif /* getmntent+hasmntopt */ if (!check_okay) - Perl_croak(aTHX_ "Can't check filesystem of script \"%s\" for nosuid", PL_origfilename); - return on_nosuid; + Perl_croak(aTHX_ "Can't check filesystem of script \"%s\" for nosuid/noexec", PL_origfilename); + if (on_nosuid) + Perl_croak(aTHX_ "Setuid script \"%s\" on nosuid filesystem", PL_origfilename); + if (on_noexec) + Perl_croak(aTHX_ "Setuid script \"%s\" on noexec filesystem", PL_origfilename); + return ((!check_okay) || on_nosuid || on_noexec); } #endif /* IAMSUID */ STATIC void -S_validate_suid(pTHX_ char *validarg, char *scriptname, int fdscript) +S_validate_suid(pTHX_ char *validarg, char *scriptname) { #ifdef IAMSUID - int which; -#endif + /* int which; */ +#endif /* IAMSUID */ /* do we need to emulate setuid on scripts? */ @@ -3117,6 +3253,13 @@ S_validate_suid(pTHX_ char *validarg, char *scriptname, int fdscript) * uid. We don't just make perl setuid root because that loses the * effective uid we had before invoking perl, if it was different from the * uid. + * PSz 27 Feb 04 + * Description/comments above do not match current workings: + * suidperl must be hardlinked to sperlN.NNN (that is what we exec); + * suidperl called with script open and name changed to /dev/fd/N/X; + * suidperl croaks if script is not setuid; + * making perl setuid would be a huge security risk (and yes, that + * would lose any euid we might have had). * * DOSUID must be defined in both perl and suidperl, and IAMSUID must * be defined in suidperl only. suidperl must be setuid root. The @@ -3128,12 +3271,33 @@ S_validate_suid(pTHX_ char *validarg, char *scriptname, int fdscript) if (PerlLIO_fstat(PerlIO_fileno(PL_rsfp),&PL_statbuf) < 0) /* normal stat is insecure */ Perl_croak(aTHX_ "Can't stat script \"%s\"",PL_origfilename); - if (fdscript < 0 && PL_statbuf.st_mode & (S_ISUID|S_ISGID)) { + if (PL_statbuf.st_mode & (S_ISUID|S_ISGID)) { I32 len; STRLEN n_a; #ifdef IAMSUID -#ifndef HAS_SETREUID + if (PL_fdscript < 0 || PL_suidscript != 1) + Perl_croak(aTHX_ "Need (suid) fdscript in suidperl\n"); /* We already checked this */ + /* PSz 11 Nov 03 + * Since the script is opened by perl, not suidperl, some of these + * checks are superfluous. Leaving them in probably does not lower + * security(?!). + */ + /* PSz 27 Feb 04 + * Do checks even for systems with no HAS_SETREUID. + * We used to swap, then re-swap UIDs with +#ifdef HAS_SETREUID + if (setreuid(PL_euid,PL_uid) < 0 + || PerlProc_getuid() != PL_euid || PerlProc_geteuid() != PL_uid) + Perl_croak(aTHX_ "Can't swap uid and euid"); +#endif +#ifdef HAS_SETREUID + if (setreuid(PL_uid,PL_euid) < 0 + || PerlProc_getuid() != PL_uid || PerlProc_geteuid() != PL_euid) + Perl_croak(aTHX_ "Can't reswap uid and euid"); +#endif + */ + /* On this access check to make sure the directories are readable, * there is actually a small window that the user could use to make * filename point to an accessible directory. So there is a faint @@ -3141,70 +3305,89 @@ S_validate_suid(pTHX_ char *validarg, char *scriptname, int fdscript) * non-accessible directory. I don't know what to do about that. * But I don't think it's too important. The manual lies when * it says access() is useful in setuid programs. + * + * So, access() is pretty useless... but not harmful... do anyway. */ - if (PerlLIO_access(CopFILE(PL_curcop),1)) /*double check*/ - Perl_croak(aTHX_ "Permission denied"); -#else + if (PerlLIO_access(CopFILE(PL_curcop),1)) { /*double check*/ + Perl_croak(aTHX_ "Can't access() script\n"); + } + /* If we can swap euid and uid, then we can determine access rights * with a simple stat of the file, and then compare device and * inode to make sure we did stat() on the same file we opened. * Then we just have to make sure he or she can execute it. + * + * PSz 24 Feb 04 + * As the script is opened by perl, not suidperl, we do not need to + * care much about access rights. + * + * The 'script changed' check is needed, or we can get lied to + * about $0 with e.g. + * suidperl /dev/fd/4//bin/x 4 4000) + Perl_croak(aTHX_ "Very long #! line"); + /* Allow more than a single space after #! */ + while (isSPACE(*s)) s++; + /* Sanity check on buffer end */ + while ((*s) && !isSPACE(*s)) s++; for (s2 = s; (s2 > SvPV(PL_linestr,n_a)+2 && (isDIGIT(s2[-1]) || strchr("._-", s2[-1]))); s2--) ; - if (strnNE(s2-4,"perl",4) && strnNE(s-9,"perl",4)) /* sanity check */ + /* Sanity check on buffer start */ + if ( (s2-4 < SvPV(PL_linestr,n_a)+2 || strnNE(s2-4,"perl",4)) && + (s-9 < SvPV(PL_linestr,n_a)+2 || strnNE(s-9,"perl",4)) ) Perl_croak(aTHX_ "Not a perl script"); while (*s == ' ' || *s == '\t') s++; /* @@ -3212,33 +3395,101 @@ S_validate_suid(pTHX_ char *validarg, char *scriptname, int fdscript) * mentioning suidperl explicitly, but they may not add any strange * arguments beyond what #! says if they do invoke suidperl that way. */ + /* + * The way validarg was set up, we rely on the kernel to start + * scripts with argv[1] set to contain all #! line switches (the + * whole line). + */ + /* + * Check that we got all the arguments listed in the #! line (not + * just that there are no extraneous arguments). Might not matter + * much, as switches from #! line seem to be acted upon (also), and + * so may be checked and trapped in perl. But, security checks must + * be done in suidperl and not deferred to perl. Note that suidperl + * does not get around to parsing (and checking) the switches on + * the #! line (but execs perl sooner). + * Allow (require) a trailing newline (which may be of two + * characters on some architectures?) (but no other trailing + * whitespace). + */ len = strlen(validarg); if (strEQ(validarg," PHOOEY ") || - strnNE(s,validarg,len) || !isSPACE(s[len])) + strnNE(s,validarg,len) || !isSPACE(s[len]) || + !(strlen(s) == len+1 || (strlen(s) == len+2 && isSPACE(s[len+1])))) Perl_croak(aTHX_ "Args must match #! line"); #ifndef IAMSUID - if (PL_euid != PL_uid && (PL_statbuf.st_mode & S_ISUID) && + if (PL_fdscript < 0 && + PL_euid != PL_uid && (PL_statbuf.st_mode & S_ISUID) && PL_euid == PL_statbuf.st_uid) if (!PL_do_undump) Perl_croak(aTHX_ "YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET!\n\ -FIX YOUR KERNEL, PUT A C WRAPPER AROUND THIS SCRIPT, OR USE -u AND UNDUMP!\n"); +FIX YOUR KERNEL, OR PUT A C WRAPPER AROUND THIS SCRIPT!\n"); #endif /* IAMSUID */ - if (PL_euid) { /* oops, we're not the setuid root perl */ - (void)PerlIO_close(PL_rsfp); + if (PL_fdscript < 0 && + PL_euid) { /* oops, we're not the setuid root perl */ + /* PSz 18 Feb 04 + * When root runs a setuid script, we do not go through the same + * steps of execing sperl and then perl with fd scripts, but + * simply set up UIDs within the same perl invocation; so do + * not have the same checks (on options, whatever) that we have + * for plain users. No problem really: would have to be a script + * that does not actually work for plain users; and if root is + * foolish and can be persuaded to run such an unsafe script, he + * might run also non-setuid ones, and deserves what he gets. + * + * Or, we might drop the PL_euid check above (and rely just on + * PL_fdscript to avoid loops), and do the execs + * even for root. + */ #ifndef IAMSUID - /* try again */ + int which; + /* PSz 11 Nov 03 + * Pass fd script to suidperl. + * Exec suidperl, substituting fd script for scriptname. + * Pass script name as "subdir" of fd, which perl will grok; + * in fact will use that to distinguish this from "normal" + * usage, see comments above. + */ + PerlIO_rewind(PL_rsfp); + PerlLIO_lseek(PerlIO_fileno(PL_rsfp),(Off_t)0,0); /* just in case rewind didn't */ + /* PSz 27 Feb 04 Sanity checks on scriptname */ + if ((!scriptname) || (!*scriptname) ) { + Perl_croak(aTHX_ "No setuid script name\n"); + } + if (*scriptname == '-') { + Perl_croak(aTHX_ "Setuid script name may not begin with dash\n"); + /* Or we might confuse it with an option when replacing + * name in argument list, below (though we do pointer, not + * string, comparisons). + */ + } + for (which = 1; PL_origargv[which] && PL_origargv[which] != scriptname; which++) ; + if (!PL_origargv[which]) { + Perl_croak(aTHX_ "Can't change argv to have fd script\n"); + } + PL_origargv[which] = savepv(Perl_form(aTHX_ "/dev/fd/%d/%s", + PerlIO_fileno(PL_rsfp), PL_origargv[which])); +#if defined(HAS_FCNTL) && defined(F_SETFD) + fcntl(PerlIO_fileno(PL_rsfp),F_SETFD,0); /* ensure no close-on-exec */ +#endif PERL_FPU_PRE_EXEC PerlProc_execv(Perl_form(aTHX_ "%s/sperl"PERL_FS_VER_FMT, BIN_EXP, (int)PERL_REVISION, (int)PERL_VERSION, (int)PERL_SUBVERSION), PL_origargv); PERL_FPU_POST_EXEC -#endif - Perl_croak(aTHX_ "Can't do setuid\n"); +#endif /* IAMSUID */ + Perl_croak(aTHX_ "Can't do setuid (cannot exec sperl)\n"); } if (PL_statbuf.st_mode & S_ISGID && PL_statbuf.st_gid != PL_egid) { +/* PSz 26 Feb 04 + * This seems back to front: we try HAS_SETEGID first; if not available + * then try HAS_SETREGID; as a last chance we try HAS_SETRESGID. May be OK + * in the sense that we only want to set EGID; but are there any machines + * with either of the latter, but not the former? Same with UID, later. + */ #ifdef HAS_SETEGID (void)setegid(PL_statbuf.st_gid); #else @@ -3292,26 +3543,64 @@ FIX YOUR KERNEL, PUT A C WRAPPER AROUND THIS SCRIPT, OR USE -u AND UNDUMP!\n"); } init_ids(); if (!cando(S_IXUSR,TRUE,&PL_statbuf)) - Perl_croak(aTHX_ "Permission denied\n"); /* they can't do this */ + Perl_croak(aTHX_ "Effective UID cannot exec script\n"); /* they can't do this */ } #ifdef IAMSUID - else if (PL_preprocess) + else if (PL_preprocess) /* PSz 13 Nov 03 Caught elsewhere, useless(?!) here */ Perl_croak(aTHX_ "-P not allowed for setuid/setgid script\n"); - else if (fdscript >= 0) - Perl_croak(aTHX_ "fd script not allowed in suidperl\n"); - else + else if (PL_fdscript < 0 || PL_suidscript != 1) + /* PSz 13 Nov 03 Caught elsewhere, useless(?!) here */ + Perl_croak(aTHX_ "(suid) fdscript needed in suidperl\n"); + else { +/* PSz 16 Sep 03 Keep neat error message */ Perl_croak(aTHX_ "Script is not setuid/setgid in suidperl\n"); + } /* We absolutely must clear out any saved ids here, so we */ /* exec the real perl, substituting fd script for scriptname. */ /* (We pass script name as "subdir" of fd, which perl will grok.) */ + /* + * It might be thought that using setresgid and/or setresuid (changed to + * set the saved IDs) above might obviate the need to exec, and we could + * go on to "do the perl thing". + * + * Is there such a thing as "saved GID", and is that set for setuid (but + * not setgid) execution like suidperl? Without exec, it would not be + * cleared for setuid (but not setgid) scripts (or might need a dummy + * setresgid). + * + * We need suidperl to do the exact same argument checking that perl + * does. Thus it cannot be very small; while it could be significantly + * smaller, it is safer (simpler?) to make it essentially the same + * binary as perl (but they are not identical). - Maybe could defer that + * check to the invoked perl, and suidperl be a tiny wrapper instead; + * but prefer to do thorough checks in suidperl itself. Such deferral + * would make suidperl security rely on perl, a design no-no. + * + * Setuid things should be short and simple, thus easy to understand and + * verify. They should do their "own thing", without influence by + * attackers. It may help if their internal execution flow is fixed, + * regardless of platform: it may be best to exec anyway. + * + * Suidperl should at least be conceptually simple: a wrapper only, + * never to do any real perl. Maybe we should put + * #ifdef IAMSUID + * Perl_croak(aTHX_ "Suidperl should never do real perl\n"); + * #endif + * into the perly bits. + */ PerlIO_rewind(PL_rsfp); PerlLIO_lseek(PerlIO_fileno(PL_rsfp),(Off_t)0,0); /* just in case rewind didn't */ - for (which = 1; PL_origargv[which] && PL_origargv[which] != scriptname; which++) ; - if (!PL_origargv[which]) - Perl_croak(aTHX_ "Permission denied"); - PL_origargv[which] = savepv(Perl_form(aTHX_ "/dev/fd/%d/%s", - PerlIO_fileno(PL_rsfp), PL_origargv[which])); + /* PSz 11 Nov 03 + * Keep original arguments: suidperl already has fd script. + */ +/* for (which = 1; PL_origargv[which] && PL_origargv[which] != scriptname; which++) ; */ +/* if (!PL_origargv[which]) { */ +/* errno = EPERM; */ +/* Perl_croak(aTHX_ "Permission denied\n"); */ +/* } */ +/* PL_origargv[which] = savepv(Perl_form(aTHX_ "/dev/fd/%d/%s", */ +/* PerlIO_fileno(PL_rsfp), PL_origargv[which])); */ #if defined(HAS_FCNTL) && defined(F_SETFD) fcntl(PerlIO_fileno(PL_rsfp),F_SETFD,0); /* ensure no close-on-exec */ #endif @@ -3320,7 +3609,7 @@ FIX YOUR KERNEL, PUT A C WRAPPER AROUND THIS SCRIPT, OR USE -u AND UNDUMP!\n"); (int)PERL_REVISION, (int)PERL_VERSION, (int)PERL_SUBVERSION), PL_origargv);/* try again */ PERL_FPU_POST_EXEC - Perl_croak(aTHX_ "Can't do setuid\n"); + Perl_croak(aTHX_ "Can't do setuid (suidperl cannot exec perl)\n"); #endif /* IAMSUID */ #else /* !DOSUID */ if (PL_euid != PL_uid || PL_egid != PL_gid) { /* (suidperl doesn't exist, in fact) */ @@ -3421,6 +3710,15 @@ S_init_ids(pTHX) /* Should not happen: */ CHECK_MALLOC_TAINT(PL_uid && (PL_euid != PL_uid || PL_egid != PL_gid)); PL_tainting |= (PL_uid && (PL_euid != PL_uid || PL_egid != PL_gid)); + /* BUG */ + /* PSz 27 Feb 04 + * Should go by suidscript, not uid!=euid: why disallow + * system("ls") in scripts run from setuid things? + * Or, is this run before we check arguments and set suidscript? + * What about SETUID_SCRIPTS_ARE_SECURE_NOW: could we use fdscript then? + * (We never have suidscript, can we be sure to have fdscript?) + * Or must then go by UID checks? See comments in forbid_setid also. + */ } /* This is used very early in the lifetime of the program, @@ -3462,10 +3760,40 @@ Perl_doing_taint(int argc, char *argv[], char *envp[]) STATIC void S_forbid_setid(pTHX_ char *s) { +#ifdef SETUID_SCRIPTS_ARE_SECURE_NOW if (PL_euid != PL_uid) Perl_croak(aTHX_ "No %s allowed while running setuid", s); if (PL_egid != PL_gid) Perl_croak(aTHX_ "No %s allowed while running setgid", s); +#endif /* SETUID_SCRIPTS_ARE_SECURE_NOW */ + /* PSz 29 Feb 04 + * Checks for UID/GID above "wrong": why disallow + * perl -e 'print "Hello\n"' + * from within setuid things?? Simply drop them: replaced by + * fdscript/suidscript and #ifdef IAMSUID checks below. + * + * This may be too late for command-line switches. Will catch those on + * the #! line, after finding the script name and setting up + * fdscript/suidscript. Note that suidperl does not get around to + * parsing (and checking) the switches on the #! line, but checks that + * the two sets are identical. + * + * With SETUID_SCRIPTS_ARE_SECURE_NOW, could we use fdscript, also or + * instead, or would that be "too late"? (We never have suidscript, can + * we be sure to have fdscript?) + * + * Catch things with suidscript (in descendant of suidperl), even with + * right UID/GID. Was already checked in suidperl, with #ifdef IAMSUID, + * below; but I am paranoid. + * + * Also see comments about root running a setuid script, elsewhere. + */ + if (PL_suidscript >= 0) + Perl_croak(aTHX_ "No %s allowed with (suid) fdscript", s); +#ifdef IAMSUID + /* PSz 11 Nov 03 Catch it in suidperl, always! */ + Perl_croak(aTHX_ "No %s allowed in suidperl", s); +#endif /* IAMSUID */ } void @@ -3486,7 +3814,7 @@ Perl_init_debugger(pTHX) sv_setiv(PL_DBtrace, 0); PL_DBsignal = GvSV((gv_fetchpv("DB::signal", GV_ADDMULTI, SVt_PV))); sv_setiv(PL_DBsignal, 0); - PL_DBassertion = GvSV((gv_fetchpv("assertion", GV_ADDMULTI, SVt_PV))); + PL_DBassertion = GvSV((gv_fetchpv("DB::assertion", GV_ADDMULTI, SVt_PV))); sv_setiv(PL_DBassertion, 0); PL_curstash = ostash; } @@ -3726,6 +4054,7 @@ S_init_postdump_symbols(pTHX_ register int argc, register char **argv, register GvMULTI_on(PL_envgv); hv = GvHVn(PL_envgv); hv_magic(hv, Nullgv, PERL_MAGIC_env); +#ifndef PERL_MICRO #ifdef USE_ENVIRON_ARRAY /* Note that if the supplied env parameter is actually a copy of the global environ then it may now point to free'd memory @@ -3746,7 +4075,7 @@ S_init_postdump_symbols(pTHX_ register int argc, register char **argv, register for (; *env; env++) { if (!(s = strchr(*env,'='))) continue; -#if defined(MSDOS) +#if defined(MSDOS) && !defined(DJGPP) *s = '\0'; (void)strupr(*env); *s = '='; @@ -3757,6 +4086,7 @@ S_init_postdump_symbols(pTHX_ register int argc, register char **argv, register mg_set(sv); } #endif /* USE_ENVIRON_ARRAY */ +#endif /* !PERL_MICRO */ } TAINT_NOT; if ((tmpgv = gv_fetchpv("$",TRUE, SVt_PV))) {