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From: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
To: syzbot <syzbot+4f2e5f086147d543ab03@syzkaller.appspotmail.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Christoph Hellwig" <hch@lst.de>,
	"Alexey Khoroshilov" <khoroshilov@ispras.ru>,
	"Artem Bityutskiy" <artem.bityutskiy@linux.intel.com>,
	"Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH 2/2] hfsplus: always return error if fill_super fails
Date: Thu, 3 May 2018 19:10:36 -0300	[thread overview]
Message-ID: <8285926250376eb393b69877251b0d6e743b7930.1525384742.git.ernesto.mnd.fernandez@gmail.com> (raw)
In-Reply-To: <dadb7856c5a0da0fa3c1f2c30f18f09fad62d45d.1525384741.git.ernesto.mnd.fernandez@gmail.com>

If the filesystem is corrupted in such a way that the HFS+ Private Data
directory is not of type HFSPLUS_FOLDER, the mount will fail without
throwing an error code. The vfs layer is then forced to dereference a
NULL root dentry.

This bug was found by KASAN while running the reproducer provided by
syzbot+4f2e5f086147d543ab03@syzkaller.appspotmail.com for a separate
issue.

Fixes: 5bd9d99d107c ("hfsplus: add error checking for hfs_find_init()")
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
---
 fs/hfsplus/super.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 4bc49e3f171d..4f62634c5666 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -524,8 +524,10 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_put_root;
 	if (!hfs_brec_read(&fd, &entry, sizeof(entry))) {
 		hfs_find_exit(&fd);
-		if (entry.type != cpu_to_be16(HFSPLUS_FOLDER))
+		if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) {
+			err = -EINVAL;
 			goto out_put_root;
+		}
 		inode = hfsplus_iget(sb, be32_to_cpu(entry.folder.id));
 		if (IS_ERR(inode)) {
 			err = PTR_ERR(inode);
-- 
2.11.0

  reply	other threads:[~2018-05-03 22:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-03 22:08 [PATCH 1/2] hfsplus: clean up delayed work " Ernesto A. Fernández
2018-05-03 22:10 ` Ernesto A. Fernández [this message]
2018-05-03 22:31 ` Al Viro
2018-05-08  1:48   ` Ernesto A. Fernández
2018-05-21  2:06     ` [PATCH v3] hfsplus: fix cleanup for hfsplus_fill_super() Ernesto A. Fernández

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