From 8d6a4d33e1c38864b064df39473f4e74ef949b36 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 19 Feb 2018 17:35:36 +0100
Subject: [PATCH] journal-file: refuse opening non-regular journal files

Let's check the file node type when we open/stat journal files: refuse
anything that is not a regular file...
---
 src/journal/journal-file.c | 6 ++++++
 src/journal/sd-journal.c   | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index 3353b3a0d8..09c511b8b8 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -651,6 +651,12 @@ static int journal_file_fstat(JournalFile *f) {
 
         f->last_stat_usec = now(CLOCK_MONOTONIC);
 
+        /* Refuse dealing with with files that aren't regular */
+        if (S_ISDIR(f->last_stat.st_mode))
+                return -EISDIR;
+        if (!S_ISREG(f->last_stat.st_mode))
+                return -EBADFD;
+
         /* Refuse appending to files that are already deleted */
         if (f->last_stat.st_nlink <= 0)
                 return -EIDRM;
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 4deee461c3..8a591205c4 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -2016,6 +2016,10 @@ _public_ int sd_journal_open_files_fd(sd_journal **ret, int fds[], unsigned n_fd
                         goto fail;
                 }
 
+                if (S_ISDIR(st.st_mode)) {
+                        r = -EISDIR;
+                        goto fail;
+                }
                 if (!S_ISREG(st.st_mode)) {
                         r = -EBADFD;
                         goto fail;