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-rw-r--r--daemon.c64
1 files changed, 60 insertions, 4 deletions
diff --git a/daemon.c b/daemon.c
index 91b96569cd..539f6e87af 100644
--- a/daemon.c
+++ b/daemon.c
@@ -82,9 +82,63 @@ static void loginfo(const char *err, ...)
va_end(params);
}
+static int avoid_alias(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;
+ }
+ }
+}
+
static char *path_ok(char *dir)
{
- char *path = enter_repo(dir, strict_paths);
+ char *path;
+
+ if (avoid_alias(dir)) {
+ logerror("'%s': aliased", dir);
+ return NULL;
+ }
+
+ path = enter_repo(dir, strict_paths);
if (!path) {
logerror("'%s': unable to chdir or not a git archive", dir);
@@ -96,9 +150,11 @@ static char *path_ok(char *dir)
int pathlen = strlen(path);
/* The validation is done on the paths after enter_repo
- * canonicalization, so whitelist should be written in
- * terms of real pathnames (i.e. after ~user is expanded
- * and symlinks resolved).
+ * appends optional {.git,.git/.git} and friends, but
+ * it does not use getcwd(). So if your /pub is
+ * a symlink to /mnt/pub, you can whitelist /pub and
+ * do not have to say /mnt/pub.
+ * Do not say /pub/.
*/
for ( pp = ok_paths ; *pp ; pp++ ) {
int len = strlen(*pp);