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* [PATCH] fs/ntfs3: fix panic about slab-out-of-bounds caused by ntfs_list_ea()
@ 2023-04-20  7:46 Zeng Heng
  2023-07-03  7:36 ` Konstantin Komarov
  0 siblings, 1 reply; 2+ messages in thread
From: Zeng Heng @ 2023-04-20  7:46 UTC (permalink / raw)
  To: almaz.alexandrovich; +Cc: weiyongjun1, xiexiuqi, ntfs3, liwei391, linux-kernel

Here is a BUG report about linux-6.1 from syzbot, but it still remains
within upstream:

BUG: KASAN: slab-out-of-bounds in ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
BUG: KASAN: slab-out-of-bounds in ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
Read of size 1 at addr ffff888021acaf3d by task syz-executor128/3632

Call Trace:
 kasan_report+0x139/0x170 mm/kasan/report.c:495
 ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
 ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
 vfs_listxattr fs/xattr.c:457 [inline]
 listxattr+0x293/0x2d0 fs/xattr.c:804
 path_listxattr fs/xattr.c:828 [inline]
 __do_sys_llistxattr fs/xattr.c:846 [inline]

Before derefering field members of `ea` in unpacked_ea_size(), we need to
check whether the EA_FULL struct is located in access validate range.

Similarly, when derefering `ea->name` field member, we need to check
whethe the ea->name is located in access validate range, too.

Fixes: be71b5cba2e6 ("fs/ntfs3: Add attrib operations")
Reported-by: syzbot+9fcea5ef6dc4dc72d334@syzkaller.appspotmail.com
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
 fs/ntfs3/xattr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
index ff64302e87e5..27eb30453b9f 100644
--- a/fs/ntfs3/xattr.c
+++ b/fs/ntfs3/xattr.c
@@ -210,11 +210,15 @@ static ssize_t ntfs_list_ea(struct ntfs_inode *ni, char *buffer,
 	size = le32_to_cpu(info->size);
 
 	/* Enumerate all xattrs. */
-	for (ret = 0, off = 0; off < size; off += ea_size) {
+	for (ret = 0, off = 0; off + sizeof(struct EA_FULL) < size; off += ea_size) {
 		ea = Add2Ptr(ea_all, off);
 		ea_size = unpacked_ea_size(ea);
 
 		if (buffer) {
+			/* Check if we can use field ea->name */
+			if (off + ea_size > size)
+				break;
+
 			if (ret + ea->name_len + 1 > bytes_per_buffer) {
 				err = -ERANGE;
 				goto out;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] fs/ntfs3: fix panic about slab-out-of-bounds caused by ntfs_list_ea()
  2023-04-20  7:46 [PATCH] fs/ntfs3: fix panic about slab-out-of-bounds caused by ntfs_list_ea() Zeng Heng
@ 2023-07-03  7:36 ` Konstantin Komarov
  0 siblings, 0 replies; 2+ messages in thread
From: Konstantin Komarov @ 2023-07-03  7:36 UTC (permalink / raw)
  To: Zeng Heng; +Cc: weiyongjun1, xiexiuqi, ntfs3, liwei391, linux-kernel

On 20.04.2023 11:46, Zeng Heng wrote:
> Here is a BUG report about linux-6.1 from syzbot, but it still remains
> within upstream:
>
> BUG: KASAN: slab-out-of-bounds in ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
> BUG: KASAN: slab-out-of-bounds in ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
> Read of size 1 at addr ffff888021acaf3d by task syz-executor128/3632
>
> Call Trace:
>   kasan_report+0x139/0x170 mm/kasan/report.c:495
>   ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
>   ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
>   vfs_listxattr fs/xattr.c:457 [inline]
>   listxattr+0x293/0x2d0 fs/xattr.c:804
>   path_listxattr fs/xattr.c:828 [inline]
>   __do_sys_llistxattr fs/xattr.c:846 [inline]
>
> Before derefering field members of `ea` in unpacked_ea_size(), we need to
> check whether the EA_FULL struct is located in access validate range.
>
> Similarly, when derefering `ea->name` field member, we need to check
> whethe the ea->name is located in access validate range, too.
>
> Fixes: be71b5cba2e6 ("fs/ntfs3: Add attrib operations")
> Reported-by: syzbot+9fcea5ef6dc4dc72d334@syzkaller.appspotmail.com
> Signed-off-by: Zeng Heng <zengheng4@huawei.com>
> ---
>   fs/ntfs3/xattr.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c
> index ff64302e87e5..27eb30453b9f 100644
> --- a/fs/ntfs3/xattr.c
> +++ b/fs/ntfs3/xattr.c
> @@ -210,11 +210,15 @@ static ssize_t ntfs_list_ea(struct ntfs_inode *ni, char *buffer,
>   	size = le32_to_cpu(info->size);
>   
>   	/* Enumerate all xattrs. */
> -	for (ret = 0, off = 0; off < size; off += ea_size) {
> +	for (ret = 0, off = 0; off + sizeof(struct EA_FULL) < size; off += ea_size) {
>   		ea = Add2Ptr(ea_all, off);
>   		ea_size = unpacked_ea_size(ea);
>   
>   		if (buffer) {
> +			/* Check if we can use field ea->name */
> +			if (off + ea_size > size)
> +				break;
> +
>   			if (ret + ea->name_len + 1 > bytes_per_buffer) {
>   				err = -ERANGE;
>   				goto out;
Thanks, your patch has been applied.

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2023-07-03  7:37 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2023-04-20  7:46 [PATCH] fs/ntfs3: fix panic about slab-out-of-bounds caused by ntfs_list_ea() Zeng Heng
2023-07-03  7:36 ` Konstantin Komarov

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