linux-kernel - [f2fs-dev] [PATCH RESEND v2] f2fs: validate before set/clear free nat bitmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <002201d35d19$3837e870$a8a7b950$@samsung.com>
Date:   Tue, 14 Nov 2017 15:20:32 +0800
From:   "LiFan" <fanofcode.li@...sung.com>
To:     "'Chao Yu'" <chao@...nel.org>, "'Chao Yu'" <yuchao0@...wei.com>,
        "'Jaegeuk Kim'" <jaegeuk@...nel.org>
Cc:     <linux-kernel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>,
        <fanofcode.li@...sung.com>
Subject: [f2fs-dev] [PATCH RESEND v2] f2fs: validate before set/clear free
 nat bitmap

In flush_nat_entries, all dirty nats will be flushed and if their new address
isn't NULL_ADDR, their bitmaps will be updated, the free_nid_count of the
bitmaps will be increased regardless of whether the nats have already been
occupied before. This could lead to wrong free_nid_count.
So this patch checks the status of the bits before actually set/clear them.

Fixes: 586d1492f301 ("f2fs: skip scanning free nid bitmap of full NAT blocks")

Signed-off-by: Fan li <fanofcode.li@...sung.com>
---
 fs/f2fs/node.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index d234c6e..b965a53 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1906,15 +1906,18 @@ static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
 	if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
 		return;
 
-	if (set)
+	if (set) {
+		if (test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
+			return;
 		__set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
-	else
-		__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
-
-	if (set)
 		nm_i->free_nid_count[nat_ofs]++;
-	else if (!build)
-		nm_i->free_nid_count[nat_ofs]--;
+	} else {
+		if (!test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
+			return;
+		__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
+		if (!build)
+			nm_i->free_nid_count[nat_ofs]--;
+	}
 }
 
 static void scan_nat_page(struct f2fs_sb_info *sbi,
--
2.7.4