From: Darrick J. Wong <djwong@kernel.org>
Date: Mon, 8 Jun 2026 17:03:09 +0000 (-0700)
Subject: mkfs: fix PATH_MAX check
X-Git-Tag: v7.1.0~13
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2df5f48fb8291f28fd07e4b097259cce82ca0172;p=thirdparty%2Fxfsprogs-dev.git

mkfs: fix PATH_MAX check

Per the snprintf manpage, the correct means to check snprintf for an
insufficiently large buffer is to check if its return value is >= @size,
not > @size.  Codex found this.

Cc: <linux-xfs@vger.kernel.org> # v6.17.0
Fixes: 8a4ea72724930c ("proto: add ability to populate a filesystem from a directory")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/mkfs/proto.c b/mkfs/proto.c
index a460aebd9..e167cba1d 100644
--- a/mkfs/proto.c
+++ b/mkfs/proto.c
@@ -1674,7 +1674,7 @@ handle_direntry(
 	/* Ensure we're within the limits of PATH_MAX. */
 	size_t avail = PATH_MAX - path_len;
 	size_t wrote = snprintf(path_buf + path_len, avail, "/%s", entry->d_name);
-	if (wrote > avail)
+	if (wrote >= avail)
 		fail(path_buf, ENAMETOOLONG);
 
 	/*