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 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: [email protected]
Signed-off-by: Chen Zhongjin <[email protected]>
---
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
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 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 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: [email protected]
> Signed-off-by: Chen Zhongjin <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Thanks,
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 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 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: [email protected]
> Signed-off-by: Chen Zhongjin <[email protected]>
> ---
> 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 <[email protected]>
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 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 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: [email protected]
Signed-off-by: Chen Zhongjin <[email protected]>
Reviewed-by: Yue Hu <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Signed-off-by: Gao Xiang <[email protected]>
---
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
On Mon, 5 Dec 2022 11:49:57 +0800
Chen Zhongjin via Linux-erofs <[email protected]> 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 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: [email protected]
> Signed-off-by: Chen Zhongjin <[email protected]>
Reviewed-by: Yue Hu <[email protected]>
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;
> }
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 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 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: [email protected]
>> Signed-off-by: Chen Zhongjin <[email protected]>
>> ---
>> 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 <[email protected]>
> 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 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 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: [email protected]
> Signed-off-by: Chen Zhongjin <[email protected]>
> Reviewed-by: Yue Hu <[email protected]>
> Reviewed-by: Gao Xiang <[email protected]>
> Signed-off-by: Gao Xiang <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Thanks,