enhance clean_pathname function

1 files changed, 17 insertions, 7 deletions

diff --git a/src/firejail/util.c b/src/firejail/util.c
index 2ad85acd6..8966521cb 100644
--- a/src/firejail/util.c
+++ b/src/firejail/util.c
@@ -544,11 +544,13 @@ char *split_comma(char *str) {
 }
 
 
-// remove consecutive and trailing slashes
-// and return allocated memory
-// e.g. /home//user/ -> /home/user
+// simplify absolute path by removing
+// 1) consecutive and trailing slashes, and
+// 2) segments with a single dot
+// for example /foo//./bar/ -> /foo/bar
 char *clean_pathname(const char *path) {
-        assert(path);
+        assert(path && path[0] == '/');
+
         size_t len = strlen(path);
         char *rv = malloc(len + 1);
         if (!rv)
@@ -557,15 +559,23 @@ char *clean_pathname(const char *path) {
         size_t i = 0;
         size_t j = 0;
         while (path[i]) {
-                while (path[i] == '/' && path[i+1] == '/')
-                        i++;
+                if (path[i] == '/') {
+                        while (path[i+1] == '/' ||
+                              (path[i+1] == '.' && path[i+2] == '/'))
+                                i++;
+                }
+
                 rv[j++] = path[i++];
         }
         rv[j] = '\0';
 
+        // remove a trailing dot
+        if (j > 1 && rv[j - 1] == '.' && rv[j - 2] == '/')
+                rv[--j] = '\0';
+
         // remove a trailing slash
         if (j > 1 && rv[j - 1] == '/')
-                rv[j - 1] = '\0';
+                rv[--j] = '\0';
 
         return rv;
 }