From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: akpm@linux-foundation.org
Cc: linux-fsdevel@vger.kernel.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Tigran Aivazian <aivazian.tigran@gmail.com>,
syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
Subject: [PATCH] bfs: add sanity check at bfs_fill_super().
Date: Wed, 9 May 2018 19:35:04 +0900 [thread overview]
Message-ID: <1525862104-3407-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> (raw)
syzbot is reporting too large memory allocation at bfs_fill_super() [1].
Since file system image is corrupted such that bfs_sb->s_start == 0,
bfs_fill_super() is trying to allocate 8MB of continuous memory. Fix this
by adding a sanity check on bfs_sb->s_start, __GFP_NOWARN and printf().
[1] https://syzkaller.appspot.com/bug?id=16a87c236b951351374a84c8a32f40edbc034e96
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
Cc: Tigran Aivazian <aivazian.tigran@gmail.com>
---
fs/bfs/inode.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index 9a69392..d81c148 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -350,7 +350,8 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
s->s_magic = BFS_MAGIC;
- if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
+ if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
+ le32_to_cpu(bfs_sb->s_start) < BFS_BSIZE) {
printf("Superblock is corrupted\n");
goto out1;
}
@@ -359,9 +360,11 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
sizeof(struct bfs_inode)
+ BFS_ROOT_INO - 1;
imap_len = (info->si_lasti / 8) + 1;
- info->si_imap = kzalloc(imap_len, GFP_KERNEL);
- if (!info->si_imap)
+ info->si_imap = kzalloc(imap_len, GFP_KERNEL | __GFP_NOWARN);
+ if (!info->si_imap) {
+ printf("Cannot allocate %u bytes\n", imap_len);
goto out1;
+ }
for (i = 0; i < BFS_ROOT_INO; i++)
set_bit(i, info->si_imap);
--
1.8.3.1
next reply other threads:[~2018-05-09 10:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-09 10:35 Tetsuo Handa [this message]
2018-05-09 23:06 ` [PATCH] bfs: add sanity check at bfs_fill_super() Andrew Morton
[not found] ` <201805092346.w49NkINl045657@www262.sakura.ne.jp>
2018-05-09 23:53 ` Andrew Morton
2018-06-13 13:33 ` Tetsuo Handa
2018-06-13 13:49 ` Tigran Aivazian
2018-06-13 16:00 ` Dmitry Vyukov
2018-06-14 12:23 ` Tigran Aivazian
2018-06-14 12:38 ` Dmitry Vyukov
2018-06-14 13:05 ` Tigran Aivazian
2018-06-14 13:12 ` Dmitry Vyukov
2018-06-14 13:28 ` Tetsuo Handa
2018-06-14 15:13 ` Tigran Aivazian
2018-06-14 16:15 ` Tigran Aivazian
2018-06-14 19:00 ` Tigran Aivazian
2018-06-14 22:18 ` Tetsuo Handa
2018-06-15 10:45 ` Tigran Aivazian
2018-06-13 22:09 ` Tetsuo Handa
2018-06-14 7:38 ` Tigran Aivazian
2018-06-14 10:45 ` Tetsuo Handa
2018-06-14 12:11 ` Tigran Aivazian
2018-05-10 0:53 ` Matthew Wilcox
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