local execution: Check validity of symlinks

Invalid entries, currently all upwards symlinks (pending
implementation of a better way of handling them), are now
identified and handled similarly to remote execution: in compatible
mode on the client side, during handling of local response, and in
native mode during the population of the local action result.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/buildtool/execution_api/common/tree_reader_utils.cpp b/src/buildtool/execution_api/common/tree_reader_utils.cpp
index 855c1842..13775201 100644
--- a/src/buildtool/execution_api/common/tree_reader_utils.cpp
+++ b/src/buildtool/execution_api/common/tree_reader_utils.cpp
@@ -106,6 +106,12 @@ auto TreeReaderUtils::ReadObjectInfos(bazel_re::Directory const& dir,
         }
 
         for (auto const& l : dir.symlinks()) {
+            // check validity of symlinks
+            if (not PathIsNonUpwards(l.target())) {
+                Logger::Log(
+                    LogLevel::Error, "found invalid symlink at {}", l.name());
+                return false;
+            }
             if (not store_info(l.name(), CreateObjectInfo(hash_function, l))) {
                 return false;
             }