From: Luca Boccassi <luca.boccassi@gmail.com>
Date: Sun, 7 Jun 2026 18:02:38 +0000 (+0100)
Subject: journal-importer: cap field size when checking
X-Git-Tag: v261-rc4~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d31694318088a908ccbced2fe95ea4657017b47;p=thirdparty%2Fsystemd.git

journal-importer: cap field size when checking

Originally reported on yeswehack.com as YWH-PGM9780-82

Follow-up for 1e448731f51865184ba988b246d02823a9284d6c
---

diff --git a/src/shared/journal-importer.c b/src/shared/journal-importer.c
index 87286a33b28..471ad879a4d 100644
--- a/src/shared/journal-importer.c
+++ b/src/shared/journal-importer.c
@@ -325,7 +325,7 @@ int journal_importer_process_data(JournalImporter *imp) {
                         if (!journal_field_valid(line, sep - line, true)) {
                                 char buf[64], *t;
 
-                                t = strndupa_safe(line, sep - line);
+                                t = strndupa_safe(line, MIN((size_t) (sep - line), sizeof buf));
                                 log_debug("Ignoring invalid field: \"%s\"",
                                           cellescape(buf, sizeof buf, t));
 
@@ -344,7 +344,7 @@ int journal_importer_process_data(JournalImporter *imp) {
                         if (!journal_field_valid(line, n - 1, true)) {
                                 char buf[64], *t;
 
-                                t = strndupa_safe(line, n - 1);
+                                t = strndupa_safe(line, MIN(n - 1, sizeof buf));
                                 log_debug("Ignoring invalid field: \"%s\"",
                                           cellescape(buf, sizeof buf, t));
 
diff --git a/test/units/TEST-04-JOURNAL.journal-remote.sh b/test/units/TEST-04-JOURNAL.journal-remote.sh
index 5d4b13d70e0..14be8a13096 100755
--- a/test/units/TEST-04-JOURNAL.journal-remote.sh
+++ b/test/units/TEST-04-JOURNAL.journal-remote.sh
@@ -310,3 +310,15 @@ systemctl stop systemd-journal-remote.{socket,service}
 rm -rf /var/log/journal/remote/*
 rm /run/systemd/journal-upload.conf.d/99-test.conf
 rm /run/systemd/journal-remote.conf.d/99-test.conf
+
+DOS_DIR="$(mktemp -d)"
+{ head -c $((5 * 1024 * 1024)) /dev/zero | tr '\0' 'A'; printf '\n'; } >"$DOS_DIR/no-separator.export"
+{ head -c $((5 * 1024 * 1024)) /dev/zero | tr '\0' 'A'; printf '=value\n'; } >"$DOS_DIR/long-field-name.export"
+for export_file in "$DOS_DIR"/no-separator.export "$DOS_DIR"/long-field-name.export; do
+    rm -f "$DOS_DIR"/*.journal
+    timeout 30 /usr/lib/systemd/systemd-journal-remote \
+                    --split-mode=none \
+                    --output="$DOS_DIR/dos.journal" \
+                    "$export_file" || [[ $? -lt 124 ]]
+done
+rm -rf "$DOS_DIR"