From: Adrian Szyndela <adrian.s@samsung.com>
Date: Mon, 9 Apr 2018 09:55:14 +0000 (+0200)
Subject: logger: fix for use-after-free in log storage
X-Git-Tag: accepted/tizen/unified/20180410.063705^0
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=refs%2Fchanges%2F23%2F175223%2F1;p=platform%2Fcore%2Fsystem%2Fdlog.git

logger: fix for use-after-free in log storage

A report from ASAN build has shown a bug while freeing a storage.

When a dumping reader was created with no available logs it
was disconnected from storage, but put into waiting_readers.

This commit changes log_storage_new_reader() in a way that
a reader is added to waiting_readers only if it is connected
to the storage.

Change-Id: Id6033fe73e86674384feb2fafb9b3814f0f0b73e
---

diff --git a/src/logger/log_storage.c b/src/logger/log_storage.c
index 44aab07..a59880d 100644
--- a/src/logger/log_storage.c
+++ b/src/logger/log_storage.c
@@ -189,7 +189,6 @@ log_storage_reader *log_storage_new_reader(log_storage *storage,
 		reader->user_data = user_data;
 		reader->current = NULL;
 		reader->counter = storage->counter_begin;
-		list_add(&storage->waiting_readers, reader);
 		reader->final = NULL;
 
 		if (dumping) {
@@ -200,6 +199,9 @@ log_storage_reader *log_storage_new_reader(log_storage *storage,
 			// but in case there are no logs - we have nothing to do
 				reader->storage = NULL;
 		}
+
+		if (NULL != reader->storage)
+			list_add(&storage->waiting_readers, reader);
 	}
 	return reader;
 }