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From: Abdun Nihaal <abdun.nihaal@gmail.com>
To: almaz.alexandrovich@paragon-software.com
Cc: linux-kernel@vger.kernel.org,
	syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com,
	ntfs3@lists.linux.dev,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH v2] fs/ntfs3: Validate attribute data and valid sizes
Date: Mon, 14 Nov 2022 17:23:14 +0530	[thread overview]
Message-ID: <20221114115314.183818-1-abdun.nihaal@gmail.com> (raw)

The data_size and valid_size fields of non resident attributes should be
less than the its alloc_size field, but this is not checked in
ntfs_read_mft function.

Syzbot reports a allocation order warning due to a large unchecked value
of data_size getting assigned to inode->i_size which is then passed to
kcalloc.

Add sanity check for ensuring that the data_size and valid_size fields
are not larger than alloc_size field.

Link: https://syzkaller.appspot.com/bug?extid=fa4648a5446460b7b963
Reported-and-tested-by: syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
---

Please apply this instead of my previous patch.

Changes in v2:
 Correct the format used for the Fixes tag.

 fs/ntfs3/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 970bb7c357c7..763dd982a43a 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -132,6 +132,13 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 	if (le16_to_cpu(attr->name_off) + attr->name_len > asize)
 		goto out;
 
+	if (attr->non_res) {
+		t64 = le64_to_cpu(attr->nres.alloc_size);
+		if (le64_to_cpu(attr->nres.data_size) > t64 ||
+		    le64_to_cpu(attr->nres.valid_size) > t64)
+			goto out;
+	}
+
 	switch (attr->type) {
 	case ATTR_STD:
 		if (attr->non_res ||
-- 
2.37.3

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Abdun Nihaal <abdun.nihaal@gmail.com>
To: almaz.alexandrovich@paragon-software.com
Cc: ntfs3@lists.linux.dev, linux-kernel@vger.kernel.org,
	skhan@linuxfoundation.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Abdun Nihaal <abdun.nihaal@gmail.com>,
	syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com
Subject: [PATCH v2] fs/ntfs3: Validate attribute data and valid sizes
Date: Mon, 14 Nov 2022 17:23:14 +0530	[thread overview]
Message-ID: <20221114115314.183818-1-abdun.nihaal@gmail.com> (raw)

The data_size and valid_size fields of non resident attributes should be
less than the its alloc_size field, but this is not checked in
ntfs_read_mft function.

Syzbot reports a allocation order warning due to a large unchecked value
of data_size getting assigned to inode->i_size which is then passed to
kcalloc.

Add sanity check for ensuring that the data_size and valid_size fields
are not larger than alloc_size field.

Link: https://syzkaller.appspot.com/bug?extid=fa4648a5446460b7b963
Reported-and-tested-by: syzbot+fa4648a5446460b7b963@syzkaller.appspotmail.com
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
---

Please apply this instead of my previous patch.

Changes in v2:
 Correct the format used for the Fixes tag.

 fs/ntfs3/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 970bb7c357c7..763dd982a43a 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -132,6 +132,13 @@ static struct inode *ntfs_read_mft(struct inode *inode,
 	if (le16_to_cpu(attr->name_off) + attr->name_len > asize)
 		goto out;
 
+	if (attr->non_res) {
+		t64 = le64_to_cpu(attr->nres.alloc_size);
+		if (le64_to_cpu(attr->nres.data_size) > t64 ||
+		    le64_to_cpu(attr->nres.valid_size) > t64)
+			goto out;
+	}
+
 	switch (attr->type) {
 	case ATTR_STD:
 		if (attr->non_res ||
-- 
2.37.3


             reply	other threads:[~2022-11-14 11:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14 11:53 Abdun Nihaal [this message]
2022-11-14 11:53 ` [PATCH v2] fs/ntfs3: Validate attribute data and valid sizes Abdun Nihaal
2022-12-26 15:32 ` Konstantin Komarov
2022-12-26 15:32   ` Konstantin Komarov via Linux-kernel-mentees

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