* [PATCH v2] erofs: Fix pcluster memleak when m_pa is zero
@ 2022-12-05 1:50 ` Chen Zhongjin via Linux-erofs
0 siblings, 0 replies; 4+ messages in thread
From: Chen Zhongjin @ 2022-12-05 1:50 UTC (permalink / raw)
To: syzbot+6f8cd9a0155b366d227f, linux-erofs, linux-kernel
Cc: chenzhongjin, xiang, chao, huyue2, jefflexu
syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
unreferenced object 0xffff88811009c7f8 (size 136):
...
backtrace:
[<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740
[<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580
[<ffffffff814bc0d6>] read_pages+0x86/0x3d0
...
syzkaller constructed a case: in z_erofs_register_pcluster(),
ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be
zero although pcl is not a inline pcluster.
Then following path adds refcount for grp, but the refcount won't be put
because pcl is inline.
z_erofs_readahead()
z_erofs_do_read_page() # for another page
z_erofs_collector_begin()
erofs_find_workgroup()
erofs_workgroup_get()
Since it's illegal for map->m_pa to be zero, add check here to avoid
registering the pcluster which would be leaked.
Fixes: cecf864d3d76 ("erofs: support inline data decompression")
Reported-by: syzbot+6f8cd9a0155b366d227f@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
As Gao's advice, we should fail to register pcluster if m_pa is zero.
Maked it this way and changed the commit message.
---
fs/erofs/zdata.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index b792d424d774..7826634f4f51 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -488,7 +488,8 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
struct erofs_workgroup *grp;
int err;
- if (!(map->m_flags & EROFS_MAP_ENCODED)) {
+ if (!(map->m_flags & EROFS_MAP_ENCODED) ||
+ !(map->m_pa >> PAGE_SHIFT)) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2] erofs: Fix pcluster memleak when m_pa is zero
@ 2022-12-05 1:50 ` Chen Zhongjin via Linux-erofs
0 siblings, 0 replies; 4+ messages in thread
From: Chen Zhongjin via Linux-erofs @ 2022-12-05 1:50 UTC (permalink / raw)
To: syzbot+6f8cd9a0155b366d227f, linux-erofs, linux-kernel
Cc: chenzhongjin, huyue2
syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
unreferenced object 0xffff88811009c7f8 (size 136):
...
backtrace:
[<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740
[<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580
[<ffffffff814bc0d6>] read_pages+0x86/0x3d0
...
syzkaller constructed a case: in z_erofs_register_pcluster(),
ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be
zero although pcl is not a inline pcluster.
Then following path adds refcount for grp, but the refcount won't be put
because pcl is inline.
z_erofs_readahead()
z_erofs_do_read_page() # for another page
z_erofs_collector_begin()
erofs_find_workgroup()
erofs_workgroup_get()
Since it's illegal for map->m_pa to be zero, add check here to avoid
registering the pcluster which would be leaked.
Fixes: cecf864d3d76 ("erofs: support inline data decompression")
Reported-by: syzbot+6f8cd9a0155b366d227f@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
As Gao's advice, we should fail to register pcluster if m_pa is zero.
Maked it this way and changed the commit message.
---
fs/erofs/zdata.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index b792d424d774..7826634f4f51 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -488,7 +488,8 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
struct erofs_workgroup *grp;
int err;
- if (!(map->m_flags & EROFS_MAP_ENCODED)) {
+ if (!(map->m_flags & EROFS_MAP_ENCODED) ||
+ !(map->m_pa >> PAGE_SHIFT)) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] erofs: Fix pcluster memleak when m_pa is zero
2022-12-05 1:50 ` Chen Zhongjin via Linux-erofs
@ 2022-12-05 3:46 ` Gao Xiang
-1 siblings, 0 replies; 4+ messages in thread
From: Gao Xiang @ 2022-12-05 3:46 UTC (permalink / raw)
To: Chen Zhongjin
Cc: syzbot+6f8cd9a0155b366d227f, linux-erofs, linux-kernel, xiang,
chao, huyue2, jefflexu
On Mon, Dec 05, 2022 at 09:50:24AM +0800, Chen Zhongjin wrote:
> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
>
> unreferenced object 0xffff88811009c7f8 (size 136):
> ...
> backtrace:
> [<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740
> [<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580
> [<ffffffff814bc0d6>] read_pages+0x86/0x3d0
> ...
>
> syzkaller constructed a case: in z_erofs_register_pcluster(),
> ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be
> zero although pcl is not a inline pcluster.
>
> Then following path adds refcount for grp, but the refcount won't be put
> because pcl is inline.
>
> z_erofs_readahead()
> z_erofs_do_read_page() # for another page
> z_erofs_collector_begin()
> erofs_find_workgroup()
> erofs_workgroup_get()
>
> Since it's illegal for map->m_pa to be zero, add check here to avoid
the block address of a pcluster to be zero,
not just map->m_pa == 0.
Also subject line needs to be updated as well,
"Fix pcluster memleak when its block address is zero"
> registering the pcluster which would be leaked.
>
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Reported-by: syzbot+6f8cd9a0155b366d227f@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Otherwise it looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
(Would you mind sending a next version for this so I can apply it?)
Thanks,
Gao Xiang
> ---
> As Gao's advice, we should fail to register pcluster if m_pa is zero.
> Maked it this way and changed the commit message.
> ---
> fs/erofs/zdata.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index b792d424d774..7826634f4f51 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -488,7 +488,8 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
> struct erofs_workgroup *grp;
> int err;
>
> - if (!(map->m_flags & EROFS_MAP_ENCODED)) {
> + if (!(map->m_flags & EROFS_MAP_ENCODED) ||
> + !(map->m_pa >> PAGE_SHIFT)) {
> DBG_BUGON(1);
> return -EFSCORRUPTED;
> }
> --
> 2.17.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] erofs: Fix pcluster memleak when m_pa is zero
@ 2022-12-05 3:46 ` Gao Xiang
0 siblings, 0 replies; 4+ messages in thread
From: Gao Xiang @ 2022-12-05 3:46 UTC (permalink / raw)
To: Chen Zhongjin
Cc: syzbot+6f8cd9a0155b366d227f, linux-kernel, huyue2, linux-erofs
On Mon, Dec 05, 2022 at 09:50:24AM +0800, Chen Zhongjin wrote:
> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
>
> unreferenced object 0xffff88811009c7f8 (size 136):
> ...
> backtrace:
> [<ffffffff821db19b>] z_erofs_do_read_page+0x99b/0x1740
> [<ffffffff821dee9e>] z_erofs_readahead+0x24e/0x580
> [<ffffffff814bc0d6>] read_pages+0x86/0x3d0
> ...
>
> syzkaller constructed a case: in z_erofs_register_pcluster(),
> ztailpacking = false and map->m_pa = zero. This makes pcl->obj.index be
> zero although pcl is not a inline pcluster.
>
> Then following path adds refcount for grp, but the refcount won't be put
> because pcl is inline.
>
> z_erofs_readahead()
> z_erofs_do_read_page() # for another page
> z_erofs_collector_begin()
> erofs_find_workgroup()
> erofs_workgroup_get()
>
> Since it's illegal for map->m_pa to be zero, add check here to avoid
the block address of a pcluster to be zero,
not just map->m_pa == 0.
Also subject line needs to be updated as well,
"Fix pcluster memleak when its block address is zero"
> registering the pcluster which would be leaked.
>
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Reported-by: syzbot+6f8cd9a0155b366d227f@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Otherwise it looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
(Would you mind sending a next version for this so I can apply it?)
Thanks,
Gao Xiang
> ---
> As Gao's advice, we should fail to register pcluster if m_pa is zero.
> Maked it this way and changed the commit message.
> ---
> fs/erofs/zdata.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index b792d424d774..7826634f4f51 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -488,7 +488,8 @@ static int z_erofs_register_pcluster(struct z_erofs_decompress_frontend *fe)
> struct erofs_workgroup *grp;
> int err;
>
> - if (!(map->m_flags & EROFS_MAP_ENCODED)) {
> + if (!(map->m_flags & EROFS_MAP_ENCODED) ||
> + !(map->m_pa >> PAGE_SHIFT)) {
> DBG_BUGON(1);
> return -EFSCORRUPTED;
> }
> --
> 2.17.1
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-12-05 3:46 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-12-05 1:50 [PATCH v2] erofs: Fix pcluster memleak when m_pa is zero Chen Zhongjin
2022-12-05 1:50 ` Chen Zhongjin via Linux-erofs
2022-12-05 3:46 ` Gao Xiang
2022-12-05 3:46 ` Gao Xiang
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