Re: [PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero

2022-12-06 Thread Chao Yu 

On 2022/12/5 14:08, Gao Xiang wrote:

Hi all,

On Mon, Dec 05, 2022 at 11:49:57AM +0800, Chen Zhongjin wrote:

syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed

unreferenced object 0x88811009c7f8 (size 136):
   ...
   backtrace:
 [] z_erofs_do_read_page+0x99b/0x1740
 [] z_erofs_readahead+0x24e/0x580
 [] 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 the block address of a pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin 
---
v1 -> v2:
As Gao's advice, we should fail to register pcluster if m_pa is zero.
Maked it this way and changed the commit message.

v2 -> v3:
Slightly fix commit message and add -next tag.


I've updated the patch itself as below
(Since we only need to fail out for non-tailpacking cases, tailpacking
  inline inodes could still have m_pa < EROFS_BLKSIZ):

 From f5e037e760d338ca0c116e507be663cb843d42f0 Mon Sep 17 00:00:00 2001
From: Chen Zhongjin 
Date: Mon, 5 Dec 2022 11:49:57 +0800
Subject: [PATCH] erofs: Fix pcluster memleak when its block address is zero

syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed

unreferenced object 0x88811009c7f8 (size 136):
   ...
   backtrace:
 [] z_erofs_do_read_page+0x99b/0x1740
 [] z_erofs_readahead+0x24e/0x580
 [] 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 the block address of a non-inlined pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin 
Reviewed-by: Yue Hu 
Reviewed-by: Gao Xiang 
Signed-off-by: Gao Xiang 


Reviewed-by: Chao Yu 

Thanks,

Re: [PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero

2022-12-04 Thread Gao Xiang 
Hi all,

On Mon, Dec 05, 2022 at 11:49:57AM +0800, Chen Zhongjin wrote:
> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
> 
> unreferenced object 0x88811009c7f8 (size 136):
>   ...
>   backtrace:
> [] z_erofs_do_read_page+0x99b/0x1740
> [] z_erofs_readahead+0x24e/0x580
> [] 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 the block address of a pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin 
> ---
> v1 -> v2:
> As Gao's advice, we should fail to register pcluster if m_pa is zero.
> Maked it this way and changed the commit message.
> 
> v2 -> v3:
> Slightly fix commit message and add -next tag.

I've updated the patch itself as below
(Since we only need to fail out for non-tailpacking cases, tailpacking
 inline inodes could still have m_pa < EROFS_BLKSIZ):

>From f5e037e760d338ca0c116e507be663cb843d42f0 Mon Sep 17 00:00:00 2001
From: Chen Zhongjin 
Date: Mon, 5 Dec 2022 11:49:57 +0800
Subject: [PATCH] erofs: Fix pcluster memleak when its block address is zero

syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed

unreferenced object 0x88811009c7f8 (size 136):
  ...
  backtrace:
[] z_erofs_do_read_page+0x99b/0x1740
[] z_erofs_readahead+0x24e/0x580
[] 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 the block address of a non-inlined pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin 
Reviewed-by: Yue Hu 
Reviewed-by: Gao Xiang 
Signed-off-by: Gao Xiang 
---
 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 2584a62c9d28..fa7ac499a825 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -496,7 +496,8 @@ 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) ||
+   (!ztailpacking && !(map->m_pa >> PAGE_SHIFT))) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
-- 
2.30.2

Re: [PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero

2022-12-04 Thread Yue Hu 
On Mon, 5 Dec 2022 11:49:57 +0800
Chen Zhongjin via Linux-erofs  wrote:

> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
> 
> unreferenced object 0x88811009c7f8 (size 136):
>   ...
>   backtrace:
> [] z_erofs_do_read_page+0x99b/0x1740
> [] z_erofs_readahead+0x24e/0x580
> [] 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 the block address of a pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin 

Reviewed-by: Yue Hu 

Thanks.

> ---
> v1 -> v2:
> As Gao's advice, we should fail to register pcluster if m_pa is zero.
> Maked it this way and changed the commit message.
> 
> v2 -> v3:
> Slightly fix commit message and add -next tag.
> ---
>  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;
>   }

Re: [PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero

2022-12-04 Thread Gao Xiang 
On Mon, Dec 05, 2022 at 11:49:57AM +0800, Chen Zhongjin wrote:
> syzkaller reported a memleak:
> https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed
> 
> unreferenced object 0x88811009c7f8 (size 136):
>   ...
>   backtrace:
> [] z_erofs_do_read_page+0x99b/0x1740
> [] z_erofs_readahead+0x24e/0x580
> [] 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 the block address of a pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
> Signed-off-by: Chen Zhongjin 

Reviewed-by: Gao Xiang 

Thanks,
Gao Xiang

[PATCH -next v3] erofs: Fix pcluster memleak when its block address is zero

2022-12-04 Thread Chen Zhongjin via Linux-erofs 
syzkaller reported a memleak:
https://syzkaller.appspot.com/bug?id=62f37ff612f0021641eda5b17f056f1668aa9aed

unreferenced object 0x88811009c7f8 (size 136):
  ...
  backtrace:
[] z_erofs_do_read_page+0x99b/0x1740
[] z_erofs_readahead+0x24e/0x580
[] 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 the block address of a pcluster 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+6f8cd9a0155b366d2...@syzkaller.appspotmail.com
Signed-off-by: Chen Zhongjin 
---
v1 -> v2:
As Gao's advice, we should fail to register pcluster if m_pa is zero.
Maked it this way and changed the commit message.

v2 -> v3:
Slightly fix commit message and add -next tag.
---
 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