sd-journal: detect earlier if we try to read an object from an invalid offset

Specifically, detect early if we try to read from offset 0, i.e. are using
uninitialized offset data.

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index ac6c30f9f259f22f26021b8d2286c288f6683dac..c4318636f71f7477509f87b1ed0d0a1a28b81b4b 100644 (file)
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -709,6 +709,10 @@ int journal_file_move_to_object(JournalFile *f, ObjectType type, uint64_t offset
         if (!VALID64(offset))
                 return -EFAULT;
 
+        /* Object may not be located in the file header */
+        if (offset < le64toh(f->header->header_size))
+                return -EBADMSG;
+
         r = journal_file_move_to(f, type, false, offset, sizeof(ObjectHeader), &t);
         if (r < 0)
                 return r;