From: Karel Zak <kzak@redhat.com>
Date: Tue, 15 Jun 2021 10:04:43 +0000 (+0200)
Subject: mkswap: fix holes detection (infinite loop and/or stack-buffer-underflow)
X-Git-Tag: v2.38-rc1~455
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a3a74160b96498d672e3652827aa7e6d7f3a120;p=thirdparty%2Futil-linux.git

mkswap: fix holes detection (infinite loop and/or stack-buffer-underflow)

Reported-by: Brian Lane <bcl@redhat.com>
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1971877
Fix: https://github.com/karelzak/util-linux/issues/1348
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c
index 27374fd721..c45a3a317e 100644
--- a/disk-utils/mkswap.c
+++ b/disk-utils/mkswap.c
@@ -267,6 +267,8 @@ static void check_extents(struct mkswap_control *ctl)
 			return;
 
 		n = fiemap->fm_mapped_extents;
+		if (n == 0)
+			break;
 
 		for (i = 0; i < n; i++) {
 			struct fiemap_extent *e = &fiemap->fm_extents[i];