From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Tue, 14 Oct 2025 09:49:34 +0000 (+0300)
Subject: maildir: Add assert to make sure dirfd() returns a valid fd
X-Git-Tag: 2.4.2~86
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=031196b7b2b672340d66448255095b17bc95a34e;p=thirdparty%2Fdovecot%2Fcore.git

maildir: Add assert to make sure dirfd() returns a valid fd
---

diff --git a/src/lib-storage/index/maildir/maildir-sync.c b/src/lib-storage/index/maildir/maildir-sync.c
index 2321f2105c..5f18fd4ab7 100644
--- a/src/lib-storage/index/maildir/maildir-sync.c
+++ b/src/lib-storage/index/maildir/maildir-sync.c
@@ -438,7 +438,9 @@ maildir_scan_dir(struct maildir_sync_context *ctx, bool new_dir, bool final,
 	}
 
 #ifdef HAVE_DIRFD
-	if (fstat(dirfd(dirp), &st) < 0) {
+	int fd = dirfd(dirp);
+	i_assert(fd != -1);
+	if (fstat(fd, &st) < 0) {
 		mailbox_set_critical(&ctx->mbox->box,
 			"fstat(%s) failed: %m", path);
 		(void)closedir(dirp);