X-Git-Url: https://mattmccutchen.net/rsync/rsync.git/blobdiff_plain/0ecfbf27c3b9e01d498201e90e7d0a89a9d0a47c..e72b18a9bd9f89847e49e87c1159c74d7bf0fbf3:/util.c

diff --git a/util.c b/util.c
index 00670db4..e5638f05 100644
--- a/util.c
+++ b/util.c
@@ -301,16 +301,15 @@ int copy_file(char *source, char *dest, mode_t mode)
 #define MAX_RENAMES 1000
 
 /**
- * 
-  Robust unlink: some OS'es (HPUX) refuse to unlink busy files, so
-  rename to <path>/.rsyncNNN instead.
-  
-  Note that successive rsync runs will shuffle the filenames around a
-  bit as long as the file is still busy; this is because this function
-  does not know if the unlink call is due to a new file coming in, or
-  --delete trying to remove old .rsyncNNN files, hence it renames it
-  each time.
-*/
+ * Robust unlink: some OS'es (HPUX) refuse to unlink busy files, so
+ * rename to <path>/.rsyncNNN instead.
+ *
+ * Note that successive rsync runs will shuffle the filenames around a
+ * bit as long as the file is still busy; this is because this function
+ * does not know if the unlink call is due to a new file coming in, or
+ * --delete trying to remove old .rsyncNNN files, hence it renames it
+ * each time.
+ **/
 int robust_unlink(char *fname)
 {
 #ifndef ETXTBSY
@@ -533,7 +532,8 @@ void glob_expand(char *base1, char **argv, int *argc, int maxargs)
 void strlower(char *s)
 {
 	while (*s) {
-		if (isupper(*s)) *s = tolower(*s);
+		if (isupper(* (unsigned char *) s))
+			*s = tolower(* (unsigned char *) s);
 		s++;
 	}
 }
@@ -590,17 +590,19 @@ void clean_fname(char *name)
 /**
  * Make path appear as if a chroot had occurred:
  *
- *    1. remove leading "/" (or replace with "." if at end)
- *    2. remove leading ".." components (except those allowed by "reldir")
- *    3. delete any other "<dir>/.." (recursively)
+ * @li 1. remove leading "/" (or replace with "." if at end)
+ *
+ * @li 2. remove leading ".." components (except those allowed by @p reldir)
+ *
+ * @li 3. delete any other "<dir>/.." (recursively)
  *
  * Can only shrink paths, so sanitizes in place.
  *
  * While we're at it, remove double slashes and "." components like
- *   clean_fname does(), but DON'T remove a trailing slash because that
+ *   clean_fname() does, but DON'T remove a trailing slash because that
  *   is sometimes significant on command line arguments.
  *
- * If "reldir" is non-null, it is a sanitized directory that the path will be
+ * If @p reldir is non-null, it is a sanitized directory that the path will be
  *    relative to, so allow as many ".." at the beginning of the path as
  *    there are components in reldir.  This is used for symbolic link targets.
  *    If reldir is non-null and the path began with "/", to be completely like
@@ -699,8 +701,10 @@ void sanitize_path(char *p, char *reldir)
 
 static char curr_dir[MAXPATHLEN];
 
-/** like chdir() but can be reversed with pop_dir() if save is set. It
-   is also much faster as it remembers where we have been */
+/**
+ * Like chdir() but can be reversed with pop_dir() if @p save is set.
+ * It is also much faster as it remembers where we have been.
+ **/
 char *push_dir(char *dir, int save)
 {
 	char *ret = curr_dir;
@@ -731,7 +735,7 @@ char *push_dir(char *dir, int save)
 	return ret;
 }
 
-/** Reverse a push_dir call */
+/** Reverse a push_dir() call */
 int pop_dir(char *dir)
 {
 	int ret;
@@ -771,6 +775,13 @@ int u_strcmp(const char *cs1, const char *cs2)
  * else's machine it might allow them to establish a symlink to
  * /etc/passwd, and then read it through a web server.
  *
+ * Null symlinks and absolute symlinks are always unsafe.
+ *
+ * Basically here we are concerned with symlinks whose target contains
+ * "..", because this might cause us to walk back up out of the
+ * transferred directory.  We are not allowed to go back up and
+ * reenter.
+ *
  * @param dest Target of the symlink in question.
  *
  * @param src Top source directory currently applicable.  Basically this
@@ -779,57 +790,52 @@ int u_strcmp(const char *cs1, const char *cs2)
  *
  * @retval True if unsafe
  * @retval False is unsafe
+ *
+ * @sa t_unsafe.c
  **/
-int unsafe_symlink(char *dest, char *src)
+int unsafe_symlink(const char *dest, const char *src)
 {
-	char *tok;
+	const char *name, *slash;
 	int depth = 0;
 
 	/* all absolute and null symlinks are unsafe */
-	if (!dest || !(*dest) || (*dest == '/')) return 1;
-
-	src = strdup(src);
-	if (!src) out_of_memory("unsafe_symlink");
+	if (!dest || !*dest || *dest == '/') return 1;
 
 	/* find out what our safety margin is */
-	for (tok=strtok(src,"/"); tok; tok=strtok(NULL,"/")) {
-		if (strcmp(tok,"..") == 0) {
+	for (name = src; (slash = strchr(name, '/')) != 0; name = slash+1) {
+		if (strncmp(name, "../", 3) == 0) {
 			depth=0;
-		} else if (strcmp(tok,".") == 0) {
+		} else if (strncmp(name, "./", 2) == 0) {
 			/* nothing */
 		} else {
 			depth++;
 		}
 	}
-	free(src);
+	if (strcmp(name, "..") == 0)
+		depth = 0;
 
-	/* drop by one to account for the filename portion */
-	depth--;
-
-	dest = strdup(dest);
-	if (!dest) out_of_memory("unsafe_symlink");
-
-	for (tok=strtok(dest,"/"); tok; tok=strtok(NULL,"/")) {
-		if (strcmp(tok,"..") == 0) {
-			depth--;
-		} else if (strcmp(tok,".") == 0) {
+	for (name = dest; (slash = strchr(name, '/')) != 0; name = slash+1) {
+		if (strncmp(name, "../", 3) == 0) {
+			/* if at any point we go outside the current directory
+			   then stop - it is unsafe */
+			if (--depth < 0)
+				return 1;
+		} else if (strncmp(name, "./", 2) == 0) {
 			/* nothing */
 		} else {
 			depth++;
 		}
-		/* if at any point we go outside the current directory then
-		   stop - it is unsafe */
-		if (depth < 0) break;
 	}
+	if (strcmp(name, "..") == 0)
+		depth--;
 
-	free(dest);
 	return (depth < 0);
 }
 
 
 /**
-   Return the date and time as a string
-*/
+ * Return the date and time as a string
+ **/
 char *timestring(time_t t)
 {
 	static char TimeBuf[200];