X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/checkpath/blobdiff_plain/de346a9e20c0463e25afea820d7578726f82d676..de1bcaacf00696ba09688b51c6c0bbfd8b60d778:/checkpath.c

diff --git a/checkpath.c b/checkpath.c
index 4cf5181..d874246 100644
--- a/checkpath.c
+++ b/checkpath.c
@@ -59,16 +59,14 @@ struct elt {
   struct elt *e_link;			/* Pointer to the next one along */
   size_t e_offset;			/* Offset of name in path string */
   unsigned e_flags;			/* Various useful flags */
+#define EF_STICKY 1u			/*   Directory has sticky bit set */
   char e_name[1];			/* Name of the directory */
 };
 
-#define f_sticky 1u			/* Directory has sticky bit set */
-
-#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 const struct elt rootnode = { 0, 0, 0 }; /* Root of the list */
 static struct elt *sp;			/* Stack pointer for list */
 static dstr d = DSTR_INIT;		/* Current path string */
 
@@ -272,13 +270,17 @@ static void report(const struct checkpath *cp, unsigned what, int verbose,
  * Arguments:	@const char *p@ = name of directory to check
  *		@struct stat *st@ = pointer to @stat@(2) block for it
  *		@const struct checkpath *cp@ = pointer to caller parameters
- *		@unsigned f@ = various flags
+ *		@unsigned f@ = various flags (@SF_...@)
  *
  * Returns:	Zero if everything's OK, else bitmask of problems.
  *
  * Use:		Performs the main load of sanity-checking on a directory.
+ *		If @SF_LAST@ is not set then sticky directories are always
+ *		acceptable.
  */
 
+#define SF_LAST 1u			/* This is the final item to check */
+
 static unsigned sanity(const char *p, struct stat *st,
 		       const struct checkpath *cp, unsigned f)
 {
@@ -288,13 +290,13 @@ static unsigned sanity(const char *p, struct stat *st,
   unsigned b;
 
   if (S_ISDIR(st->st_mode) &&
-      (!(f & f_last) || (cp->cp_what & CP_STICKYOK)))
-    stickyok = 01000;
+      (!(f & SF_LAST) || (cp->cp_what & CP_STICKYOK)))
+    stickyok = S_ISVTX;
 
   /* --- Check for world-writability --- */
 
   if ((cp->cp_what & CP_WRWORLD) &&
-      (st->st_mode & (0002 | stickyok)) == 0002) {
+      (st->st_mode & (S_IWOTH | stickyok)) == S_IWOTH) {
     bad |= CP_WRWORLD;
     report(cp, CP_WRWORLD, 1, p, "** world writable **");
   }
@@ -302,7 +304,7 @@ static unsigned sanity(const char *p, struct stat *st,
   /* --- Check for group-writability --- */
 
   if ((cp->cp_what & (CP_WRGRP | CP_WROTHGRP)) &&
-      (st->st_mode & (0020 | stickyok)) == 0020) {
+      (st->st_mode & (S_IWGRP | stickyok)) == S_IWGRP) {
     b = CP_WRGRP;
 
     if (cp->cp_what & CP_WROTHGRP) {
@@ -350,10 +352,11 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
   struct elt *e, *ee;
   struct stat st;
   unsigned bad = 0;
+  dstr buf = DSTR_INIT;
 
   /* --- Initialize stack pointer and path string --- */
 
-  sp = &rootnode;
+  sp = (/*unconst*/ struct elt *)&rootnode;
   dstr_destroy(&d);
 
   /* --- Try to find the current directory --- */
@@ -417,11 +420,11 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
     /* --- Handle symbolic links specially --- */
 
     if (S_ISLNK(st.st_mode)) {
-      dstr buf = DSTR_INIT;
       int i;
 
       /* --- Resolve the link --- */
 
+      dstr_reset(&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");
@@ -439,7 +442,7 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
        */
 
       if ((cp->cp_what & CP_WROTHUSR) &&
-	  (sp->e_link->e_flags & f_sticky) &&
+	  (sp->e_link->e_flags & EF_STICKY) &&
 	  st.st_uid != cp->cp_uid && st.st_uid != 0) {
 	bad |= CP_WROTHUSR;
 	report(cp, CP_WROTHUSR, 1, d.buf,
@@ -453,17 +456,16 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
       else
 	pop();
       ee = splitpath(buf.buf, ee);
-      dstr_destroy(&buf);
       continue;
     }
 
     /* --- Run the sanity check on this path element --- */
 
-    bad |= sanity(d.buf, &st, cp, ee ? 0 : f_last);
+    bad |= sanity(d.buf, &st, cp, ee ? 0 : SF_LAST);
 
     if (S_ISDIR(st.st_mode)) {
-      if (st.st_mode & 01000)
-	sp->e_flags |= f_sticky;
+      if (st.st_mode & S_ISVTX)
+	sp->e_flags |= EF_STICKY;
       report(cp, CP_REPORT, 4, d.buf, "directory");
       continue;
     }
@@ -486,6 +488,7 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
   }
 
   popall();
+  dstr_destroy(&buf);
   return (bad);
 }