X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=applets%2Fapplets.c;h=bf6b16026efa1fa7373a1911cb5b527772b0b98b;hb=f51d2069ff3a38be49a86212e1d62f2fd89c5943;hp=4af569de305ad482045f9ccc863a3b5071ebed0a;hpb=2faee7b1ed84698ae057ac44bdb0a9f686dd945f;p=oweals%2Fbusybox.git diff --git a/applets/applets.c b/applets/applets.c index 4af569de3..bf6b16026 100644 --- a/applets/applets.c +++ b/applets/applets.c @@ -29,23 +29,31 @@ #include #include #include +#include #include "busybox.h" +const char usage_messages[] = + +#define MAKE_USAGE +#include "usage.h" + +#include "applets.h" + +; + +#undef MAKE_USAGE #undef APPLET #undef APPLET_NOUSAGE #undef PROTOTYPES #include "applets.h" -struct BB_applet *applet_using; + +static struct BB_applet *applet_using; /* The -1 arises because of the {0,NULL,0,-1} entry above. */ const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1); -#ifdef CONFIG_FEATURE_SUID - -static void check_suid (struct BB_applet *app); - #ifdef CONFIG_FEATURE_SUID_CONFIG #include @@ -53,10 +61,6 @@ static void check_suid (struct BB_applet *app); #include "pwd_.h" #include "grp_.h" -static int parse_config_file (void); - -static int config_ok; - #define CONFIG_FILE "/etc/busybox.conf" /* applets [] is const, so we have to define this "override" structure */ @@ -69,131 +73,274 @@ struct BB_suid_config mode_t m_mode; struct BB_suid_config *m_next; -}; +} static *suid_config; -static struct BB_suid_config *suid_config; - -#endif /* CONFIG_FEATURE_SUID_CONFIG */ - -#endif /* CONFIG_FEATURE_SUID */ +static int suid_cfg_readable; +/* check if u is member of group g */ +static int ingroup (uid_t u, gid_t g) +{ + struct group *grp = getgrgid (g); + if (grp) { + char **mem; -extern void -bb_show_usage (void) -{ - const char *format_string; - const char *usage_string = usage_messages; - int i; + for (mem = grp->gr_mem; *mem; mem++) { + struct passwd *pwd = getpwnam (*mem); - for (i = applet_using - applets; i > 0;) { - if (!*usage_string++) { - --i; + if (pwd && (pwd->pw_uid == u)) + return 1; } } - - format_string = "%s\n\nUsage: %s %s\n\n"; - if (*usage_string == '\b') - format_string = "%s\n\nNo help available.\n\n"; - fprintf (stderr, format_string, bb_msg_full_version, applet_using->name, - usage_string); - - exit (EXIT_FAILURE); + return 0; } -static int -applet_name_compare (const void *x, const void *y) +/* This should probably be a libbb routine. In that case, + * I'd probably rename it to something like bb_trimmed_slice. + */ +static char *get_trimmed_slice(char *s, char *e) { - const char *name = x; - const struct BB_applet *applet = y; + /* First, consider the value at e to be nul and back up until we + * reach a non-space char. Set the char after that (possibly at + * the original e) to nul. */ + while (e-- > s) { + if (!isspace(*e)) { + break; + } + } + e[1] = 0; - return strcmp (name, applet->name); + /* Next, advance past all leading space and return a ptr to the + * first non-space char; possibly the terminating nul. */ + return (char *) bb_skip_whitespace(s); } -extern const size_t NUM_APPLETS; -struct BB_applet * -find_applet_by_name (const char *name) -{ - return bsearch (name, applets, NUM_APPLETS, sizeof (struct BB_applet), - applet_name_compare); -} +#define parse_error(x) { err=x; goto pe_label; } -void -run_applet_by_name (const char *name, int argc, char **argv) -{ - static int recurse_level = 0; - extern int been_there_done_that; /* From busybox.c */ +/* Don't depend on the tools to combine strings. */ +static const char config_file[] = CONFIG_FILE; -#ifdef CONFIG_FEATURE_SUID_CONFIG - if (recurse_level == 0) - config_ok = parse_config_file (); -#endif +/* There are 4 chars + 1 nul for each of user/group/other. */ +static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-"; + +/* We don't supply a value for the nul, so an index adjustment is + * necessary below. Also, we use unsigned short here to save some + * space even though these are really mode_t values. */ +static const unsigned short mode_mask[] = { + /* SST sst xxx --- */ + S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */ + S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */ + 0, S_IXOTH, S_IXOTH, 0 /* other */ +}; - recurse_level++; - /* Do a binary search to find the applet entry given the name. */ - if ((applet_using = find_applet_by_name (name)) != NULL) { - bb_applet_name = applet_using->name; - if (argv[1] && strcmp (argv[1], "--help") == 0) { - if (strcmp (applet_using->name, "busybox") == 0) { - if (argv[2]) - applet_using = find_applet_by_name (argv[2]); - else - applet_using = NULL; - } - if (applet_using) - bb_show_usage (); - been_there_done_that = 1; - busybox_main (0, NULL); +static void parse_config_file(void) +{ + struct BB_suid_config *sct_head; + struct BB_suid_config *sct; + struct BB_applet *applet; + FILE *f; + char *err; + char *s; + char *e; + int i, lc, section; + char buffer[256]; + struct stat st; + + assert(!suid_config); /* Should be set to NULL by bss init. */ + + if ((stat(config_file, &st) != 0) /* No config file? */ + || !S_ISREG(st.st_mode) /* Not a regular file? */ + || (st.st_uid != 0) /* Not owned by root? */ + || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */ + || !(f = fopen(config_file, "r")) /* Can not open? */ + ) { + return; } -#ifdef CONFIG_FEATURE_SUID - check_suid (applet_using); -#endif - exit ((*(applet_using->main)) (argc, argv)); - } - /* Just in case they have renamed busybox - Check argv[1] */ - if (recurse_level == 1) { - run_applet_by_name ("busybox", argc, argv); - } - recurse_level--; -} + suid_cfg_readable = 1; + sct_head = NULL; + section = lc = 0; + do { + s = buffer; -#ifdef CONFIG_FEATURE_SUID + if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */ + if (ferror(f)) { /* Make sure it wasn't a read error. */ + parse_error("reading"); + } + fclose(f); + suid_config = sct_head; /* Success, so set the pointer. */ + return; + } -#ifdef CONFIG_FEATURE_SUID_CONFIG + lc++; /* Got a (partial) line. */ + + /* If a line is too long for our buffer, we consider it an error. + * The following test does mistreat one corner case though. + * If the final line of the file does not end with a newline and + * yet exactly fills the buffer, it will be treated as too long + * even though there isn't really a problem. But it isn't really + * worth adding code to deal with such an unlikely situation, and + * we do err on the side of caution. Besides, the line would be + * too long if it did end with a newline. */ + if (!strchr(s, '\n') && !feof(f)) { + parse_error("line too long"); + } -/* check if u is member of group g */ -static int -ingroup (uid_t u, gid_t g) -{ - struct group *grp = getgrgid (g); + /* Trim leading and trailing whitespace, ignoring comments, and + * check if the resulting string is empty. */ + if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) { + continue; + } - if (grp) { - char **mem; + /* Check for a section header. */ + + if (*s == '[') { + /* Unlike the old code, we ignore leading and trailing + * whitespace for the section name. We also require that + * there are no stray characters after the closing bracket. */ + if (!(e = strchr(s, ']')) /* Missing right bracket? */ + || e[1] /* Trailing characters? */ + || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */ + ) { + parse_error("section header"); + } + /* Right now we only have one section so just check it. + * If more sections are added in the future, please don't + * resort to cascading ifs with multiple strcasecmp calls. + * That kind of bloated code is all too common. A loop + * and a string table would be a better choice unless the + * number of sections is very small. */ + if (strcasecmp(s, "SUID") == 0) { + section = 1; + continue; + } + section = -1; /* Unknown section so set to skip. */ + continue; + } - for (mem = grp->gr_mem; *mem; mem++) { - struct passwd *pwd = getpwnam (*mem); + /* Process sections. */ - if (pwd && (pwd->pw_uid == u)) - return 1; + if (section == 1) { /* SUID */ + /* Since we trimmed leading and trailing space above, we're + * now looking for strings of the form + * [::space::]*=[::space::]* + * where both key and value could contain inner whitespace. */ + + /* First get the key (an applet name in our case). */ + if (!!(e = strchr(s, '='))) { + s = get_trimmed_slice(s, e); + } + if (!e || !*s) { /* Missing '=' or empty key. */ + parse_error("keyword"); + } + + /* Ok, we have an applet name. Process the rhs if this + * applet is currently built in and ignore it otherwise. + * Note: This can hide config file bugs which only pop + * up when the busybox configuration is changed. */ + if ((applet = find_applet_by_name(s))) { + /* Note: We currently don't check for duplicates! + * The last config line for each applet will be the + * one used since we insert at the head of the list. + * I suppose this could be considered a feature. */ + sct = xmalloc(sizeof(struct BB_suid_config)); + sct->m_applet = applet; + sct->m_mode = 0; + sct->m_next = sct_head; + sct_head = sct; + + /* Get the specified mode. */ + + e = (char *) bb_skip_whitespace(e+1); + + for (i=0 ; i < 3 ; i++) { + const char *q; + if (!*(q = strchrnul(mode_chars + 5*i, *e++))) { + parse_error("mode"); + } + /* Adjust by -i to account for nul. */ + sct->m_mode |= mode_mask[(q - mode_chars) - i]; + } + + /* Now get the the user/group info. */ + + s = (char *) bb_skip_whitespace(e); + + /* Note: We require whitespace between the mode and the + * user/group info. */ + if ((s == e) || !(e = strchr(s, '.'))) { + parse_error("."); + } + *e++ = 0; + + /* We can't use get_ug_id here since it would exit() + * if a uid or gid was not found. Oh well... */ + { + char *e2; + + sct->m_uid = strtoul(s, &e2, 10); + if (*e2 || (s == e2)) { + struct passwd *pwd; + if (!(pwd = getpwnam(s))) { + parse_error("user"); + } + sct->m_uid = pwd->pw_uid; + } + + sct->m_gid = strtoul(e, &e2, 10); + if (*e2 || (e == e2)) { + struct group *grp; + if (!(grp = getgrnam(e))) { + parse_error("group"); + } + sct->m_gid = grp->gr_gid; + } + } + } + continue; + } + + /* Unknown sections are ignored. */ + + /* Encountering configuration lines prior to seeing a + * section header is treated as an error. This is how + * the old code worked, but it may not be desirable. + * We may want to simply ignore such lines in case they + * are used in some future version of busybox. */ + if (!section) { + parse_error("keyword outside section"); + } + + } while (1); + + pe_label: + fprintf(stderr, "Parse error in %s, line %d: %s\n", + config_file, lc, err); + + fclose(f); + /* Release any allocated memory before returning. */ + while (sct_head) { + sct = sct_head->m_next; + free(sct_head); + sct_head = sct; } - } - return 0; + return; } -#endif - +#else +#define parse_config_file(x) +#endif /* CONFIG_FEATURE_SUID_CONFIG */ -void -check_suid (struct BB_applet *applet) +#ifdef CONFIG_FEATURE_SUID +static void check_suid (struct BB_applet *applet) { uid_t ruid = getuid (); /* real [ug]id */ uid_t rgid = getgid (); #ifdef CONFIG_FEATURE_SUID_CONFIG - if (config_ok) { + if (suid_cfg_readable) { struct BB_suid_config *sct; for (sct = suid_config; sct; sct = sct->m_next) { @@ -250,205 +397,72 @@ check_suid (struct BB_applet *applet) setuid (ruid); } } +#else +#define check_suid(x) +#endif /* CONFIG_FEATURE_SUID */ -#ifdef CONFIG_FEATURE_SUID_CONFIG -#define parse_error(x) { err=x; goto pe_label; } -int -parse_config_file (void) +extern void bb_show_usage (void) { - struct stat st; - char *err = 0; - FILE *f = 0; - int lc = 0; - - suid_config = 0; - - /* is there a config file ? */ - if (stat (CONFIG_FILE, &st) == 0) { - /* is it owned by root with no write perm. for group and others ? */ - if (S_ISREG (st.st_mode) && (st.st_uid == 0) - && (!(st.st_mode & (S_IWGRP | S_IWOTH)))) { - /* that's ok .. then try to open it */ - f = fopen (CONFIG_FILE, "r"); - - if (f) { - char buffer[256]; - int section = 0; - - while (fgets (buffer, sizeof (buffer) - 1, f)) { - char c = buffer[0]; - char *p; - - lc++; - - p = strchr (buffer, '#'); - if (p) - *p = 0; - p = buffer + bb_strlen (buffer); - while ((p > buffer) && isspace (*--p)) - *p = 0; - - if (p == buffer) - continue; + const char *format_string; + const char *usage_string = usage_messages; + int i; - if (c == '[') { - p = strchr (buffer, ']'); + for (i = applet_using - applets; i > 0;) { + if (!*usage_string++) { + --i; + } + } - if (!p || (p == (buffer + 1))) /* no matching ] or empty [] */ - parse_error ("malformed section header"); + format_string = "%s\n\nUsage: %s %s\n\n"; + if (*usage_string == '\b') + format_string = "%s\n\nNo help available.\n\n"; + fprintf (stderr, format_string, bb_msg_full_version, applet_using->name, + usage_string); - *p = 0; + exit (EXIT_FAILURE); +} - if (strcasecmp (buffer + 1, "SUID") == 0) - section = 1; - else - section = -1; /* unknown section - just skip */ - } else if (section) { - switch (section) { - case 1:{ /* SUID */ - int l; - struct BB_applet *applet; +static int applet_name_compare (const void *x, const void *y) +{ + const char *name = x; + const struct BB_applet *applet = y; - p = strchr (buffer, '='); /* [::space::]*=[::space::]* */ + return strcmp (name, applet->name); +} - if (!p || (p == (buffer + 1))) /* no = or key is empty */ - parse_error ("malformed keyword"); +extern const size_t NUM_APPLETS; - l = p - buffer; - while (isspace (buffer[--l])) { - /* skip whitespace */ - } +struct BB_applet *find_applet_by_name (const char *name) +{ + return bsearch (name, applets, NUM_APPLETS, sizeof (struct BB_applet), + applet_name_compare); +} - buffer[l + 1] = 0; - - if ((applet = find_applet_by_name (buffer))) { - struct BB_suid_config *sct = - xmalloc (sizeof (struct BB_suid_config)); - - sct->m_applet = applet; - sct->m_next = suid_config; - suid_config = sct; - - while (isspace (*++p)) { - /* skip whitespace */ - } - - sct->m_mode = 0; - - switch (*p++) { - case 'S': - sct->m_mode |= S_ISUID; - break; - case 's': - sct->m_mode |= S_ISUID; - /* no break */ - case 'x': - sct->m_mode |= S_IXUSR; - break; - case '-': - break; - default: - parse_error ("invalid user mode"); - } - - switch (*p++) { - case 's': - sct->m_mode |= S_ISGID; - /* no break */ - case 'x': - sct->m_mode |= S_IXGRP; - break; - case 'S': - break; - case '-': - break; - default: - parse_error ("invalid group mode"); - } - - switch (*p) { - case 't': - case 'x': - sct->m_mode |= S_IXOTH; - break; - case 'T': - case '-': - break; - default: - parse_error ("invalid other mode"); - } - - while (isspace (*++p)) { - /* skip whitespace */ - } - - if (isdigit (*p)) { - sct->m_uid = strtol (p, &p, 10); - if (*p++ != '.') - parse_error ("parsing ."); - } else { - struct passwd *pwd; - char *p2 = strchr (p, '.'); - - if (!p2) - parse_error ("parsing ."); - - *p2 = 0; - pwd = getpwnam (p); - - if (!pwd) - parse_error ("invalid user name"); - - sct->m_uid = pwd->pw_uid; - p = p2 + 1; - } - if (isdigit (*p)) - sct->m_gid = strtol (p, &p, 10); - else { - struct group *grp = getgrnam (p); - - if (!grp) - parse_error ("invalid group name"); - - sct->m_gid = grp->gr_gid; - } - } - break; - } - default: /* unknown - skip */ - break; - } - } else - parse_error ("keyword not within section"); - } - fclose (f); - return 1; - } +void run_applet_by_name (const char *name, int argc, char **argv) +{ + if(ENABLE_FEATURE_SUID_CONFIG) parse_config_file (); + + if(!strncmp(name, "busybox", 7)) busybox_main(argc, argv); + /* Do a binary search to find the applet entry given the name. */ + applet_using = find_applet_by_name(name); + if(applet_using) { + bb_applet_name = applet_using->name; + if(argc==2 && !strcmp(argv[1], "--help")) bb_show_usage (); + if(ENABLE_FEATURE_SUID) check_suid (applet_using); + exit ((*(applet_using->main)) (argc, argv)); } - } - return 0; /* no config file or not readable (not an error) */ - -pe_label: - fprintf (stderr, "Parse error in %s, line %d: %s\n", CONFIG_FILE, lc, err); - - if (f) - fclose (f); - return 0; } -#endif - -#endif /* END CODE */ /* -Local Variables: -c-file-style: "linux" -c-basic-offset: 4 -tab-width: 4 + Local Variables: + c-file-style: "linux" + c-basic-offset: 4 + tab-width: 4 End: */