adbd: fix spurious failure to create dirs when pushing.

When pushing to a path, we first try to ensure the directory path
exists and has the permissions expected by fs_config. Due to a change
that changed the fs_config check from a blacklist to a whitelist, we
started doing this for /data (which doesn't begin with /data/), and the
UID/GID for that path was accidentally being reused for following path
segments that didn't exist, leading to a failed attempt to chown
/data/local/tmp/foo to be owned by system.

Bug: http://b/110953234
Test: python test_device.py
Change-Id: Ie798eec48bcf54aea40f6d90cc03bb2170280ee8

1 files changed, 12 insertions, 6 deletions

diff --git a/adb/daemon/file_sync_service.cpp b/adb/daemon/file_sync_service.cpp
index 11289934e..f7be8f94b 100644
--- a/adb/daemon/file_sync_service.cpp
+++ b/adb/daemon/file_sync_service.cpp
@@ -69,17 +69,23 @@ static bool update_capabilities(const char* path, uint64_t capabilities) {
 }
 
 static bool secure_mkdirs(const std::string& path) {
-    uid_t uid = -1;
-    gid_t gid = -1;
-    unsigned int mode = 0775;
-    uint64_t capabilities = 0;
-
     if (path[0] != '/') return false;
 
     std::vector<std::string> path_components = android::base::Split(path, "/");
     std::string partial_path;
     for (const auto& path_component : path_components) {
-        if (partial_path.back() != OS_PATH_SEPARATOR) partial_path += OS_PATH_SEPARATOR;
+        uid_t uid = -1;
+        gid_t gid = -1;
+        unsigned int mode = 0775;
+        uint64_t capabilities = 0;
+
+        if (path_component.empty()) {
+            continue;
+        }
+
+        if (partial_path.empty() || partial_path.back() != OS_PATH_SEPARATOR) {
+            partial_path += OS_PATH_SEPARATOR;
+        }
         partial_path += path_component;
 
         if (should_use_fs_config(partial_path)) {