2022-11-22 11:03:13

by Chen Zhongjin

Subject: [PATCH] fs/ntfs3: Fix memory leak if ntfs_read_mft failed

Label ATTR_ROOT in ntfs_read_mft() sets is_root = true and
ni->ni_flags |= NI_FLAG_DIR, then next attr will goto label ATTR_ALLOC
and alloc ni->dir.alloc_run. However two states are not always
consistent and can make memory leak.

1) attr_name in ATTR_ROOT does not fit the condition it will set
is_root = true but NI_FLAG_DIR is not set.
2) next attr_name in ATTR_ALLOC fits the condition and alloc
ni->dir.alloc_run
3) in cleanup function ni_clear(), when NI_FLAG_DIR is set, it frees
ni->dir.alloc_run, otherwise it frees ni->file.run
4) because NI_FLAG_DIR is not set in this case, ni->dir.alloc_run is
leaked as kmemleak reported:

unreferenced object 0xffff888003bc5480 (size 64):
backtrace:
[<000000003d42e6b0>] __kmalloc_node+0x4e/0x1c0
[<00000000d8e19b8a>] kvmalloc_node+0x39/0x1f0
[<00000000fc3eb5b8>] run_add_entry+0x18a/0xa40 [ntfs3]
[<0000000011c9f978>] run_unpack+0x75d/0x8e0 [ntfs3]
[<00000000e7cf1819>] run_unpack_ex+0xbc/0x500 [ntfs3]
[<00000000bbf0a43d>] ntfs_iget5+0xb25/0x2dd0 [ntfs3]
[<00000000a6e50693>] ntfs_fill_super+0x218d/0x3580 [ntfs3]
[<00000000b9170608>] get_tree_bdev+0x3fb/0x710
[<000000004833798a>] vfs_get_tree+0x8e/0x280
[<000000006e20b8e6>] path_mount+0xf3c/0x1930
[<000000007bf15a5f>] do_mount+0xf3/0x110
...

Fix this by always setting is_root and NI_FLAG_DIR together.

Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Chen Zhongjin <[email protected]>
---
fs/ntfs3/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index d5a3afbbbfd8..b7f60624b044 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -247,7 +247,6 @@ static struct inode *ntfs_read_mft(struct inode *inode,
goto out;

root = Add2Ptr(attr, roff);
- is_root = true;

if (attr->name_len != ARRAY_SIZE(I30_NAME) ||
memcmp(attr_name(attr), I30_NAME, sizeof(I30_NAME)))
@@ -260,6 +259,7 @@ static struct inode *ntfs_read_mft(struct inode *inode,
if (!is_dir)
goto next_attr;

+ is_root = true;
ni->ni_flags |= NI_FLAG_DIR;

err = indx_init(&ni->dir, sbi, attr, INDEX_MUTEX_I30);
--
2.17.1

2022-12-26 16:30:50

by Konstantin Komarov

Subject: Re: [PATCH] fs/ntfs3: Fix memory leak if ntfs_read_mft failed

On 22.11.2022 13:24, Chen Zhongjin wrote:
> Label ATTR_ROOT in ntfs_read_mft() sets is_root = true and
> ni->ni_flags |= NI_FLAG_DIR, then next attr will goto label ATTR_ALLOC
> and alloc ni->dir.alloc_run. However two states are not always
> consistent and can make memory leak.
>
> 1) attr_name in ATTR_ROOT does not fit the condition it will set
> is_root = true but NI_FLAG_DIR is not set.
> 2) next attr_name in ATTR_ALLOC fits the condition and alloc
> ni->dir.alloc_run
> 3) in cleanup function ni_clear(), when NI_FLAG_DIR is set, it frees
> ni->dir.alloc_run, otherwise it frees ni->file.run
> 4) because NI_FLAG_DIR is not set in this case, ni->dir.alloc_run is
> leaked as kmemleak reported:
>
> unreferenced object 0xffff888003bc5480 (size 64):
> backtrace:
> [<000000003d42e6b0>] __kmalloc_node+0x4e/0x1c0
> [<00000000d8e19b8a>] kvmalloc_node+0x39/0x1f0
> [<00000000fc3eb5b8>] run_add_entry+0x18a/0xa40 [ntfs3]
> [<0000000011c9f978>] run_unpack+0x75d/0x8e0 [ntfs3]
> [<00000000e7cf1819>] run_unpack_ex+0xbc/0x500 [ntfs3]
> [<00000000bbf0a43d>] ntfs_iget5+0xb25/0x2dd0 [ntfs3]
> [<00000000a6e50693>] ntfs_fill_super+0x218d/0x3580 [ntfs3]
> [<00000000b9170608>] get_tree_bdev+0x3fb/0x710
> [<000000004833798a>] vfs_get_tree+0x8e/0x280
> [<000000006e20b8e6>] path_mount+0xf3c/0x1930
> [<000000007bf15a5f>] do_mount+0xf3/0x110
> ...
>
> Fix this by always setting is_root and NI_FLAG_DIR together.
>
> Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
> Signed-off-by: Chen Zhongjin <[email protected]>
> ---
> fs/ntfs3/inode.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
> index d5a3afbbbfd8..b7f60624b044 100644
> --- a/fs/ntfs3/inode.c
> +++ b/fs/ntfs3/inode.c
> @@ -247,7 +247,6 @@ static struct inode *ntfs_read_mft(struct inode *inode,
> goto out;
>
> root = Add2Ptr(attr, roff);
> - is_root = true;
>
> if (attr->name_len != ARRAY_SIZE(I30_NAME) ||
> memcmp(attr_name(attr), I30_NAME, sizeof(I30_NAME)))
> @@ -260,6 +259,7 @@ static struct inode *ntfs_read_mft(struct inode *inode,
> if (!is_dir)
> goto next_attr;
>
> + is_root = true;
> ni->ni_flags |= NI_FLAG_DIR;
>
> err = indx_init(&ni->dir, sbi, attr, INDEX_MUTEX_I30);
Thanks for patch, applied!