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-rw-r--r--path.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/path.c b/path.c
index 047fdb0..c7679be 100644
--- a/path.c
+++ b/path.c
@@ -564,3 +564,50 @@ char *strip_path_suffix(const char *path, const char *suffix)
return NULL;
return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
}
+
+int daemon_avoid_alias(const char *p)
+{
+ int sl, ndot;
+
+ /*
+ * This resurrects the belts and suspenders paranoia check by HPA
+ * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
+ * does not do getcwd() based path canonicalizations.
+ *
+ * sl becomes true immediately after seeing '/' and continues to
+ * be true as long as dots continue after that without intervening
+ * non-dot character.
+ */
+ if (!p || (*p != '/' && *p != '~'))
+ return -1;
+ sl = 1; ndot = 0;
+ p++;
+
+ while (1) {
+ char ch = *p++;
+ if (sl) {
+ if (ch == '.')
+ ndot++;
+ else if (ch == '/') {
+ if (ndot < 3)
+ /* reject //, /./ and /../ */
+ return -1;
+ ndot = 0;
+ }
+ else if (ch == 0) {
+ if (0 < ndot && ndot < 3)
+ /* reject /.$ and /..$ */
+ return -1;
+ return 0;
+ }
+ else
+ sl = ndot = 0;
+ }
+ else if (ch == 0)
+ return 0;
+ else if (ch == '/') {
+ sl = 1;
+ ndot = 0;
+ }
+ }
+}