shared/logs-show: fix mixup between length-based memory duplication and string operations

We'd look for a '=' separator using memchr, i.e. ignoring any nul bytes in the
string, but then do a strndup, which would terminate on any nul byte, and then
again do a memcmp, which would access memory past the chunk allocated by strndup.

Of course, we probably shouldn't allow keys with nul bytes in them. But we
currently do, so there might be journal files like that out there. So let's fix
the journal-reading code first.

diff --git a/src/shared/logs-show.c b/src/shared/logs-show.c
index 50326fde5da3886d5aa6cf95560afdb70d23d7ef..124fa838b3c3b93ef1c0b2fd2a34f918bbdbcaeb 100644 (file)
--- a/src/shared/logs-show.c
+++ b/src/shared/logs-show.c
@@ -839,7 +839,7 @@ static int output_json(
                 if (!eq)
                         continue;
 
-                n = strndup(data, eq - (const char*) data);
+                n = memdup_suffix0(data, eq - (const char*) data);
                 if (!n) {
                         r = log_oom();
                         goto finish;
@@ -891,7 +891,7 @@ static int output_json(
 
                         m = eq - (const char*) data;
 
-                        n = strndup(data, m);
+                        n = memdup_suffix0(data, m);
                         if (!n) {
                                 r = log_oom();
                                 goto finish;

diff --git a/test/fuzz-regressions/fuzz-journal-remote/crash-96dee870ea66d03e89ac321eee28ea63a9b9aa45 b/test/fuzz-regressions/fuzz-journal-remote/crash-96dee870ea66d03e89ac321eee28ea63a9b9aa45
new file mode 100644 (file)
index 0000000..535d49e
Binary files /dev/null and b/test/fuzz-regressions/fuzz-journal-remote/crash-96dee870ea66d03e89ac321eee28ea63a9b9aa45 differ