#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <assert.h>
#include "busybox.h"
#undef APPLET
#include "pwd_.h"
#include "grp_.h"
-static int parse_config_file (void);
-
-static int config_ok;
+static void parse_config_file (void);
#define CONFIG_FILE "/etc/busybox.conf"
#ifdef CONFIG_FEATURE_SUID_CONFIG
if (recurse_level == 0)
- config_ok = parse_config_file ();
+ parse_config_file ();
#endif
recurse_level++;
uid_t rgid = getgid ();
#ifdef CONFIG_FEATURE_SUID_CONFIG
- if (config_ok) {
+ if (suid_config) {
struct BB_suid_config *sct;
for (sct = suid_config; sct; sct = sct->m_next) {
#ifdef CONFIG_FEATURE_SUID_CONFIG
+/* 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)
+{
+ /* 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;
+
+ /* 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);
+}
+
#define parse_error(x) { err=x; goto pe_label; }
+/* Don't depend on the tools to combine strings. */
+static const char config_file[] = CONFIG_FILE;
+
+/* 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 */
+};
-int
-parse_config_file (void)
+static void parse_config_file(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;
+ 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;
+ }
+
+ sct_head = NULL;
+ section = lc = 0;
+
+ do {
+ s = buffer;
- if (c == '[') {
- p = strchr (buffer, ']');
+ 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;
+ }
- if (!p || (p == (buffer + 1))) /* no matching ] or empty [] */
- parse_error ("malformed section header");
+ 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");
+ }
+
+ /* Trim leading and trailing whitespace, ignoring comments, and
+ * check if the resulting string is empty. */
+ if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
+ continue;
+ }
- *p = 0;
+ /* 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;
+ }
- 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;
+ /* Process sections. */
- p = strchr (buffer, '='); /* <key>[::space::]*=[::space::]*<value> */
+ if (section == 1) { /* SUID */
+ /* Since we trimmed leading and trailing space above, we're
+ * now looking for strings of the form
+ * <key>[::space::]*=[::space::]*<value>
+ * where both key and value could contain inner whitespace. */
- if (!p || (p == (buffer + 1))) /* no = or key is empty */
- parse_error ("malformed keyword");
+ /* 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");
+ }
- l = p - buffer;
- while (isspace (buffer[--l])) {
- /* skip whitespace */
+ /* 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];
}
- 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 <uid>.<gid>");
- } else {
- struct passwd *pwd;
- char *p2 = strchr (p, '.');
-
- if (!p2)
- parse_error ("parsing <uid>.<gid>");
-
- *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;
- }
+ /* 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("<uid>.<gid>");
+ }
+ *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;
+ }
}
- break;
- }
- default: /* unknown - skip */
- break;
}
- } else
- parse_error ("keyword not within section");
+ continue;
}
- fclose (f);
- return 1;
- }
- }
- }
- 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);
+ /* Unknown sections are ignored. */
- if (f)
- fclose (f);
- return 0;
+ /* 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 desireable.
+ * 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;
}
#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:
*/
projects / oweals / busybox.git / commitdiff