1 files changed, 23 insertions, 20 deletions

diff --git a/src/lib/libc/stdlib/realpath.c b/src/lib/libc/stdlib/realpath.c
index e349b7e068..1525d0372f 100644
--- a/src/lib/libc/stdlib/realpath.c
+++ b/src/lib/libc/stdlib/realpath.c
@@ -13,11 +13,7 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *      This product includes software developed by the University of
- *      California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
@@ -35,8 +31,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-/*static char sccsid[] = "from: @(#)realpath.c  8.1 (Berkeley) 2/16/94";*/
-static char *rcsid = "$Id: realpath.c,v 1.1.1.1 1995/10/18 08:42:19 deraadt Exp $";
+static char *rcsid = "$OpenBSD: realpath.c,v 1.10 2003/08/01 21:04:59 millert Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
@@ -61,15 +56,20 @@ realpath(path, resolved)
         char *resolved;
 {
         struct stat sb;
-        int fd, n, rootd, serrno;
+        int fd, n, needslash, serrno;
         char *p, *q, wbuf[MAXPATHLEN];
+        int symlinks = 0;
 
         /* Save the starting point. */
         if ((fd = open(".", O_RDONLY)) < 0) {
-                (void)strcpy(resolved, ".");
+                (void)strlcpy(resolved, ".", MAXPATHLEN);
                 return (NULL);
         }
 
+        /* Convert "." -> "" to optimize away a needless lstat() and chdir() */
+        if (path[0] == '.' && path[1] == '\0')
+                path = "";
+
         /*
          * Find the dirname and basename from the path to be resolved.
          * Change directory to the dirname component.
@@ -78,8 +78,7 @@ realpath(path, resolved)
          *     if it is a directory, then change to that directory.
          * get the current directory name and append the basename.
          */
-        (void)strncpy(resolved, path, MAXPATHLEN - 1);
-        resolved[MAXPATHLEN - 1] = '\0';
+        strlcpy(resolved, path, MAXPATHLEN);
 loop:
         q = strrchr(resolved, '/');
         if (q != NULL) {
@@ -99,9 +98,13 @@ loop:
                 p = resolved;
 
         /* Deal with the last component. */
-        if (lstat(p, &sb) == 0) {
+        if (*p != '\0' && lstat(p, &sb) == 0) {
                 if (S_ISLNK(sb.st_mode)) {
-                        n = readlink(p, resolved, MAXPATHLEN);
+                        if (++symlinks > MAXSYMLINKS) {
+                                errno = ELOOP;
+                                goto err1;
+                        }
+                        n = readlink(p, resolved, MAXPATHLEN-1);
                         if (n < 0)
                                 goto err1;
                         resolved[n] = '\0';
@@ -118,7 +121,7 @@ loop:
          * Save the last component name and get the full pathname of
          * the current directory.
          */
-        (void)strcpy(wbuf, p);
+        (void)strlcpy(wbuf, p, sizeof wbuf);
         if (getcwd(resolved, MAXPATHLEN) == 0)
                 goto err1;
 
@@ -127,18 +130,18 @@ loop:
          * happens if the last component is empty, or the dirname is root.
          */
         if (resolved[0] == '/' && resolved[1] == '\0')
-                rootd = 1;
+                needslash = 0;
         else
-                rootd = 0;
+                needslash = 1;
 
         if (*wbuf) {
-                if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
+                if (strlen(resolved) + strlen(wbuf) + needslash >= MAXPATHLEN) {
                         errno = ENAMETOOLONG;
                         goto err1;
                 }
-                if (rootd == 0)
-                        (void)strcat(resolved, "/");
-                (void)strcat(resolved, wbuf);
+                if (needslash)
+                        strlcat(resolved, "/", MAXPATHLEN);
+                strlcat(resolved, wbuf, MAXPATHLEN);
         }
 
         /* Go back to where we came from. */