X-Git-Url: https://git.distorted.org.uk/~mdw/checkpath/blobdiff_plain/558a9b222e80151fb6d97ce1c7109fc4bd877780..2422994b351992769be18b4fccf33d9b59669969:/checkpath.c diff --git a/checkpath.c b/checkpath.c index f470d49..e594201 100644 --- a/checkpath.c +++ b/checkpath.c @@ -1,13 +1,11 @@ /* -*-c-*- * - * $Id: checkpath.c,v 1.2 1999/05/18 20:49:12 mdw Exp $ - * * Check a path for safety * * (c) 1999 Mark Wooding */ -/*----- Licensing notice --------------------------------------------------* +/*----- Licensing notice --------------------------------------------------* * * This file is part of chkpath. * @@ -15,30 +13,21 @@ * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. - * + * * chkpath is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. - * + * * You should have received a copy of the GNU General Public License * along with chkpath; if not, write to the Free Software Foundation, * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -/*----- Revision history --------------------------------------------------* - * - * $Log: checkpath.c,v $ - * Revision 1.2 1999/05/18 20:49:12 mdw - * Use a dynamic string for reading symlinks. - * - * Revision 1.1.1.1 1999/04/06 20:12:07 mdw - * Import new project. - * - */ - /*----- Header files ------------------------------------------------------*/ +#include "config.h" + #include #include #include @@ -54,8 +43,9 @@ #include #include +#include -#include "path.h" +#include "checkpath.h" /*----- Data structures ---------------------------------------------------*/ @@ -72,19 +62,15 @@ struct elt { char e_name[1]; /* Name of the directory */ }; -enum { - f_sticky = 1 /* Directory has sticky bit set */ -}; +#define f_sticky 1u /* Directory has sticky bit set */ -enum { - f_last = 1 /* This is the final item to check */ -}; +#define f_last 1u /* This is the final item to check */ /*----- Static variables --------------------------------------------------*/ static struct elt rootnode = { 0, 0, 0 }; /* Root of the list */ static struct elt *sp; /* Stack pointer for list */ -static dstr d; /* Current path string */ +static dstr d = DSTR_INIT; /* Current path string */ /*----- Main code ---------------------------------------------------------*/ @@ -167,10 +153,7 @@ static void pop(void) */ static void popall(void) -{ - while (sp->e_link) - pop(); -} + { while (sp->e_link) pop(); } /* --- @push@ --- * * @@ -192,8 +175,8 @@ static void push(struct elt *e) /* --- @report@ --- * * - * Arguments: @struct chkpath *cp@ = pointer to context - * @int what@ = what sort of report is this? + * Arguments: @const struct checkpath *cp@ = pointer to context + * @unsigned what@ = what sort of report is this? * @int verbose@ = how verbose is this? * @const char *p@ = what path does it refer to? * @const char *msg@ = the message to give to the user @@ -203,86 +186,92 @@ static void push(struct elt *e) * Use: Formats and presents messages to the client. */ -static void report(struct chkpath *cp, int what, int verbose, +static void report(const struct checkpath *cp, unsigned what, int verbose, const char *p, const char *msg, ...) { + dstr d = DSTR_INIT; + va_list ap; + const char *q = msg; + const char *s; + size_t n; + int e = errno; + uid_t u; + struct passwd *pw; + gid_t g; + struct group *gr; + /* --- Decide whether to bin this message --- */ if (!cp->cp_report || verbose > cp->cp_verbose || !(cp->cp_what & what)) return; + /* --- If no reporting, do the easy thing --- */ + + if (!(cp->cp_what & CP_REPORT)) { + cp->cp_report(what, verbose, p, 0, cp->cp_arg); + return; + } + /* --- Format the message nicely --- */ - if (cp->cp_what & CP_REPORT) { - dstr d; - va_list ap; - const char *q = msg; - size_t n; - int e = errno; - - dstr_create(&d); - va_start(ap, msg); - if (verbose > 1) - dstr_puts(&d, "[ "); - if (p) - dstr_putf(&d, "Path: %s: ", p); - while (*q) { - if (*q == '%') { - q++; - switch (*q) { - case 'e': - dstr_puts(&d, strerror(e)); - break; - case 'u': { - uid_t u = (uid_t)va_arg(ap, int); - struct passwd *pw = getpwuid(u); - if (pw) - dstr_putf(&d, "`%s'", pw->pw_name); - else - dstr_putf(&d, "%i", (int)u); - } break; - case 'g': { - gid_t g = (gid_t)va_arg(ap, int); - struct group *gr = getgrgid(g); - if (gr) - dstr_putf(&d, "`%s'", gr->gr_name); - else - dstr_putf(&d, "%i", (int)g); - } break; - case 's': { - const char *s = va_arg(ap, const char *); - dstr_puts(&d, s); - } break; - case '%': - dstr_putc(&d, '%'); - break; - default: - dstr_putc(&d, '%'); - dstr_putc(&d, *q); - break; - } - q++; - } else { - n = strcspn(q, "%"); - DPUTM(&d, q, n); - q += n; + va_start(ap, msg); + if (verbose > 1) + dstr_puts(&d, "[ "); + if (p) + dstr_putf(&d, "Path: %s: ", p); + while (*q) { + if (*q == '%') { + q++; + switch (*q) { + case 'e': + dstr_puts(&d, strerror(e)); + break; + case 'u': + u = (uid_t)va_arg(ap, int); + if ((pw = getpwuid(u)) != 0) + dstr_putf(&d, "`%s'", pw->pw_name); + else + dstr_putf(&d, "%i", (int)u); + break; + case 'g': + g = (gid_t)va_arg(ap, int); + if ((gr = getgrgid(g)) != 0) + dstr_putf(&d, "`%s'", gr->gr_name); + else + dstr_putf(&d, "%i", (int)g); + break; + case 's': + s = va_arg(ap, const char *); + dstr_puts(&d, s); + break; + case '%': + dstr_putc(&d, '%'); + break; + default: + dstr_putc(&d, '%'); + dstr_putc(&d, *q); + break; } + q++; + } else { + n = strcspn(q, "%"); + DPUTM(&d, q, n); + q += n; } - if (verbose > 1) - dstr_puts(&d, " ]"); - DPUTZ(&d); - cp->cp_report(what, verbose, p, d.buf, cp->cp_arg); - dstr_destroy(&d); - va_end(ap); - } else - cp->cp_report(what, verbose, p, 0, cp->cp_arg); + } + if (verbose > 1) + dstr_puts(&d, " ]"); + DPUTZ(&d); + cp->cp_report(what, verbose, p, d.buf, cp->cp_arg); + dstr_destroy(&d); + va_end(ap); } /* --- @sanity@ --- * * * Arguments: @const char *p@ = name of directory to check * @struct stat *st@ = pointer to @stat@(2) block for it - * @struct chkpath *cp@ = pointer to caller parameters + * @const struct checkpath *cp@ = pointer to caller parameters * @unsigned f@ = various flags * * Returns: Zero if everything's OK, else bitmask of problems. @@ -290,16 +279,22 @@ static void report(struct chkpath *cp, int what, int verbose, * Use: Performs the main load of sanity-checking on a directory. */ -static int sanity(const char *p, struct stat *st, - struct chkpath *cp, unsigned f) +static unsigned sanity(const char *p, struct stat *st, + const struct checkpath *cp, unsigned f) { - int bad = 0; - int sticky = (cp->cp_what & CP_STICKYOK) || !(f & f_last) ? 01000 : 0; + unsigned bad = 0; + int stickyok = 0; + int i; + unsigned b; + + if (S_ISDIR(st->st_mode) && + (!(f & f_last) || (cp->cp_what & CP_STICKYOK))) + stickyok = 01000; /* --- Check for world-writability --- */ if ((cp->cp_what & CP_WRWORLD) && - (st->st_mode & (0002 | sticky)) == 0002) { + (st->st_mode & (0002 | stickyok)) == 0002) { bad |= CP_WRWORLD; report(cp, CP_WRWORLD, 1, p, "** world writable **"); } @@ -307,19 +302,20 @@ static int sanity(const char *p, struct stat *st, /* --- Check for group-writability --- */ if ((cp->cp_what & (CP_WRGRP | CP_WROTHGRP)) && - (st->st_mode & (0020 | sticky)) == 0020) { - if (cp->cp_what & CP_WRGRP) { - bad |= CP_WRGRP; - report(cp, CP_WRGRP, 1, p, "writable by group %g", st->st_gid); - } else { - int i; + (st->st_mode & (0020 | stickyok)) == 0020) { + b = CP_WRGRP; + + if (cp->cp_what & CP_WROTHGRP) { + b = CP_WROTHGRP; for (i = 0; i < cp->cp_gids; i++) { if (st->st_gid == cp->cp_gid[i]) - goto good_gid; + b = cp->cp_what & CP_WRGRP; } - bad |= CP_WROTHGRP; - report(cp, CP_WROTHGRP, 1, p, "writable by group %g", st->st_gid); - good_gid:; + } + if (b) { + bad |= b; + report(cp, b, 1, p, "writable by %sgroup %g", + (b == CP_WROTHGRP) ? "other " : "", st->st_gid); } } @@ -337,10 +333,10 @@ static int sanity(const char *p, struct stat *st, return (bad); } -/* --- @path_check@ --- * +/* --- @checkpath@ --- * * * Arguments: @const char *p@ = directory name which needs checking - * @struct chkpath *cp@ = caller parameters for the check + * @const struct checkpath *cp@ = parameters for the check * * Returns: Zero if all is well, otherwise bitmask of problems. * @@ -348,14 +344,14 @@ static int sanity(const char *p, struct stat *st, * users could do to it. */ -int path_check(const char *p, struct chkpath *cp) +unsigned checkpath(const char *p, const struct checkpath *cp) { char cwd[PATH_MAX]; struct elt *e, *ee; struct stat st; - int bad = 0; + unsigned bad = 0; - /* --- Initialise stack pointer and path string --- */ + /* --- Initialize stack pointer and path string --- */ sp = &rootnode; dstr_destroy(&d); @@ -421,12 +417,11 @@ int path_check(const char *p, struct chkpath *cp) /* --- Handle symbolic links specially --- */ if (S_ISLNK(st.st_mode)) { - dstr buf; + dstr buf = DSTR_INIT; int i; /* --- Resolve the link --- */ - dstr_create(&buf); dstr_ensure(&buf, st.st_size + 1); if ((i = readlink(d.buf, buf.buf, buf.sz)) < 0) { report(cp, CP_ERROR, 0, d.buf, "can't readlink: %e"); @@ -494,30 +489,95 @@ int path_check(const char *p, struct chkpath *cp) return (bad); } -/* --- @path_setids@ --- * +/* --- @checkpath_addgid@ --- * * - * Arguments: @struct chkpath *cp@ = pointer to block to fill in + * Arguments: @struct checkpath *cp@ = pointer to block to fill in + * @gid_t g@ = group id to add * - * Returns: Zero if OK, else @-1@. + * Returns: Zero if successful, nonzero if the array is full. * - * Use: Fills in the user ids and things in the structure. + * Use: Adds the group @g@ to the structure. */ -void path_setids(struct chkpath *cp) +int checkpath_addgid(struct checkpath *cp, gid_t g) { - int n, i; - gid_t g = getgid(); + int i; - cp->cp_uid = getuid(); - n = getgroups(sizeof(cp->cp_gid) / sizeof(cp->cp_gid[0]), cp->cp_gid); - - for (i = 0; i < n; i++) { + for (i = 0; i < cp->cp_gids; i++) { if (cp->cp_gid[i] == g) - goto gid_ok; + return (0); + } + if (cp->cp_gids >= N(cp->cp_gid)) + return (-1); + cp->cp_gid[cp->cp_gids++] = g; + return (0); +} + +/* --- @checkpath_setuid@ --- * + * + * Arguments: @struct checkpath *cp@ = pointer to block to fill in + * + * Returns: --- + * + * Use: Fills in the @cp_uid@ slot of the structure with the real uid + * of the current process. + */ + +void checkpath_setuid(struct checkpath *cp) { cp->cp_uid = getuid(); } + +/* --- @checkpath_setgid@ --- * + * + * Arguments: @struct checkpath *cp@ = pointer to block to fill in + * + * Returns: Zero if successful, nonzero if the array is full. + * + * Use: Adds the real gid of the current process to the @cp_gid@ + * array. + */ + +int checkpath_setgid(struct checkpath *cp) + { return (checkpath_addgid(cp, getgid())); } + +/* --- @checkpath_setgroups@ --- * + * + * Arguments: @struct checkpath *cp@ = pointer to block to fill in + * + * Returns: Zero if successful, nonzero if the array is full. + * + * Use: Adds the current process's supplementary groups to the + * @cp_gid@ table. + */ + +int checkpath_setgroups(struct checkpath *cp) +{ + int i, n; + gid_t gg[NGROUPS_MAX]; + + n = getgroups(N(gg), gg); + for (i = 0; i < n; i++) { + if (checkpath_addgid(cp, gg[i])) + return (-1); } - cp->cp_gid[n++] = g; -gid_ok: - cp->cp_gids = n; + return (0); +} + +/* --- @checkpath_setids@ --- * + * + * Arguments: @struct checkpath *cp@ = pointer to block to fill in + * + * Returns: --- + * + * Use: Fills in the user ids and things in the structure. This is + * equivalent to setting @cp_gids = 0@ and then calling + * @_setuid@, @_setgid@ and @_setgroups@. It can't fail. + */ + +void checkpath_setids(struct checkpath *cp) +{ + cp->cp_gids = 0; + checkpath_setuid(cp); + checkpath_setgid(cp); + checkpath_setgroups(cp); } /*----- That's all, folks -------------------------------------------------*/