When we mount a jffs2 image, assume that the first few blocks of
the image are normal and contain at least one xattr-related inode,
but the next block is abnormal. As a result, an error is returned
in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
called in jffs2_build_filesystem() and then again in
jffs2_do_fill_super().
Finally we can observe the following report:
==================================================================
BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
Read of size 8 at addr ffff8881243384e0 by task mount/719
Call Trace:
dump_stack+0x115/0x16b
jffs2_clear_xattr_subsystem+0x95/0x6ac
jffs2_do_fill_super+0x84f/0xc30
jffs2_fill_super+0x2ea/0x4c0
mtd_get_sb+0x254/0x400
mtd_get_sb_by_nr+0x4f/0xd0
get_tree_mtd+0x498/0x840
jffs2_get_tree+0x25/0x30
vfs_get_tree+0x8d/0x2e0
path_mount+0x50f/0x1e50
do_mount+0x107/0x130
__se_sys_mount+0x1c5/0x2f0
__x64_sys_mount+0xc7/0x160
do_syscall_64+0x45/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Allocated by task 719:
kasan_save_stack+0x23/0x60
__kasan_kmalloc.constprop.0+0x10b/0x120
kasan_slab_alloc+0x12/0x20
kmem_cache_alloc+0x1c0/0x870
jffs2_alloc_xattr_ref+0x2f/0xa0
jffs2_scan_medium.cold+0x3713/0x4794
jffs2_do_mount_fs.cold+0xa7/0x2253
jffs2_do_fill_super+0x383/0xc30
jffs2_fill_super+0x2ea/0x4c0
[...]
Freed by task 719:
kmem_cache_free+0xcc/0x7b0
jffs2_free_xattr_ref+0x78/0x98
jffs2_clear_xattr_subsystem+0xa1/0x6ac
jffs2_do_mount_fs.cold+0x5e6/0x2253
jffs2_do_fill_super+0x383/0xc30
jffs2_fill_super+0x2ea/0x4c0
[...]
The buggy address belongs to the object at ffff8881243384b8
which belongs to the cache jffs2_xattr_ref of size 48
The buggy address is located 40 bytes inside of
48-byte region [ffff8881243384b8, ffff8881243384e8)
[...]
==================================================================
The triggering of the BUG is shown in the following stack:
-----------------------------------------------------------
jffs2_fill_super
jffs2_do_fill_super
jffs2_do_mount_fs
jffs2_build_filesystem
jffs2_scan_medium
jffs2_scan_eraseblock <--- ERROR
jffs2_clear_xattr_subsystem <--- free
jffs2_clear_xattr_subsystem <--- free again
-----------------------------------------------------------
An error is returned in jffs2_do_mount_fs(). If the error is returned
by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
be executed. If the error is returned by jffs2_build_filesystem(), the
jffs2_clear_xattr_subsystem() also does not need to be executed again.
So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
to fix this UAF problem.
Fixes: aa98d7cf59b5 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
Cc: [email protected]
Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Baokun Li <[email protected]>
---
fs/jffs2/fs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 2ac410477c4f..71f03a5d36ed 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -603,8 +603,8 @@ int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc)
jffs2_free_ino_caches(c);
jffs2_free_raw_node_refs(c);
kvfree(c->blocks);
- out_inohash:
jffs2_clear_xattr_subsystem(c);
+ out_inohash:
kfree(c->inocache_list);
out_wbuf:
jffs2_flash_cleanup(c);
--
2.31.1
?? 2021/12/28 20:54, Baokun Li д??:
ping
> When we mount a jffs2 image, assume that the first few blocks of
> the image are normal and contain at least one xattr-related inode,
> but the next block is abnormal. As a result, an error is returned
> in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
> called in jffs2_build_filesystem() and then again in
> jffs2_do_fill_super().
>
> Finally we can observe the following report:
> ==================================================================
> BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
> Read of size 8 at addr ffff8881243384e0 by task mount/719
>
> Call Trace:
> dump_stack+0x115/0x16b
> jffs2_clear_xattr_subsystem+0x95/0x6ac
> jffs2_do_fill_super+0x84f/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> mtd_get_sb+0x254/0x400
> mtd_get_sb_by_nr+0x4f/0xd0
> get_tree_mtd+0x498/0x840
> jffs2_get_tree+0x25/0x30
> vfs_get_tree+0x8d/0x2e0
> path_mount+0x50f/0x1e50
> do_mount+0x107/0x130
> __se_sys_mount+0x1c5/0x2f0
> __x64_sys_mount+0xc7/0x160
> do_syscall_64+0x45/0x70
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Allocated by task 719:
> kasan_save_stack+0x23/0x60
> __kasan_kmalloc.constprop.0+0x10b/0x120
> kasan_slab_alloc+0x12/0x20
> kmem_cache_alloc+0x1c0/0x870
> jffs2_alloc_xattr_ref+0x2f/0xa0
> jffs2_scan_medium.cold+0x3713/0x4794
> jffs2_do_mount_fs.cold+0xa7/0x2253
> jffs2_do_fill_super+0x383/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> [...]
>
> Freed by task 719:
> kmem_cache_free+0xcc/0x7b0
> jffs2_free_xattr_ref+0x78/0x98
> jffs2_clear_xattr_subsystem+0xa1/0x6ac
> jffs2_do_mount_fs.cold+0x5e6/0x2253
> jffs2_do_fill_super+0x383/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> [...]
>
> The buggy address belongs to the object at ffff8881243384b8
> which belongs to the cache jffs2_xattr_ref of size 48
> The buggy address is located 40 bytes inside of
> 48-byte region [ffff8881243384b8, ffff8881243384e8)
> [...]
> ==================================================================
>
> The triggering of the BUG is shown in the following stack:
> -----------------------------------------------------------
> jffs2_fill_super
> jffs2_do_fill_super
> jffs2_do_mount_fs
> jffs2_build_filesystem
> jffs2_scan_medium
> jffs2_scan_eraseblock <--- ERROR
> jffs2_clear_xattr_subsystem <--- free
> jffs2_clear_xattr_subsystem <--- free again
> -----------------------------------------------------------
>
> An error is returned in jffs2_do_mount_fs(). If the error is returned
> by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
> be executed. If the error is returned by jffs2_build_filesystem(), the
> jffs2_clear_xattr_subsystem() also does not need to be executed again.
> So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
> to fix this UAF problem.
>
> Fixes: aa98d7cf59b5 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
> Cc: [email protected]
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Baokun Li <[email protected]>
> ---
> fs/jffs2/fs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
> index 2ac410477c4f..71f03a5d36ed 100644
> --- a/fs/jffs2/fs.c
> +++ b/fs/jffs2/fs.c
> @@ -603,8 +603,8 @@ int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc)
> jffs2_free_ino_caches(c);
> jffs2_free_raw_node_refs(c);
> kvfree(c->blocks);
> - out_inohash:
> jffs2_clear_xattr_subsystem(c);
> + out_inohash:
> kfree(c->inocache_list);
> out_wbuf:
> jffs2_flash_cleanup(c);
A gentle ping, sorry for the noise.
在 2021/12/28 20:54, Baokun Li 写道:
> When we mount a jffs2 image, assume that the first few blocks of
> the image are normal and contain at least one xattr-related inode,
> but the next block is abnormal. As a result, an error is returned
> in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
> called in jffs2_build_filesystem() and then again in
> jffs2_do_fill_super().
>
> Finally we can observe the following report:
> ==================================================================
> BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
> Read of size 8 at addr ffff8881243384e0 by task mount/719
>
> Call Trace:
> dump_stack+0x115/0x16b
> jffs2_clear_xattr_subsystem+0x95/0x6ac
> jffs2_do_fill_super+0x84f/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> mtd_get_sb+0x254/0x400
> mtd_get_sb_by_nr+0x4f/0xd0
> get_tree_mtd+0x498/0x840
> jffs2_get_tree+0x25/0x30
> vfs_get_tree+0x8d/0x2e0
> path_mount+0x50f/0x1e50
> do_mount+0x107/0x130
> __se_sys_mount+0x1c5/0x2f0
> __x64_sys_mount+0xc7/0x160
> do_syscall_64+0x45/0x70
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Allocated by task 719:
> kasan_save_stack+0x23/0x60
> __kasan_kmalloc.constprop.0+0x10b/0x120
> kasan_slab_alloc+0x12/0x20
> kmem_cache_alloc+0x1c0/0x870
> jffs2_alloc_xattr_ref+0x2f/0xa0
> jffs2_scan_medium.cold+0x3713/0x4794
> jffs2_do_mount_fs.cold+0xa7/0x2253
> jffs2_do_fill_super+0x383/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> [...]
>
> Freed by task 719:
> kmem_cache_free+0xcc/0x7b0
> jffs2_free_xattr_ref+0x78/0x98
> jffs2_clear_xattr_subsystem+0xa1/0x6ac
> jffs2_do_mount_fs.cold+0x5e6/0x2253
> jffs2_do_fill_super+0x383/0xc30
> jffs2_fill_super+0x2ea/0x4c0
> [...]
>
> The buggy address belongs to the object at ffff8881243384b8
> which belongs to the cache jffs2_xattr_ref of size 48
> The buggy address is located 40 bytes inside of
> 48-byte region [ffff8881243384b8, ffff8881243384e8)
> [...]
> ==================================================================
>
> The triggering of the BUG is shown in the following stack:
> -----------------------------------------------------------
> jffs2_fill_super
> jffs2_do_fill_super
> jffs2_do_mount_fs
> jffs2_build_filesystem
> jffs2_scan_medium
> jffs2_scan_eraseblock <--- ERROR
> jffs2_clear_xattr_subsystem <--- free
> jffs2_clear_xattr_subsystem <--- free again
> -----------------------------------------------------------
>
> An error is returned in jffs2_do_mount_fs(). If the error is returned
> by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
> be executed. If the error is returned by jffs2_build_filesystem(), the
> jffs2_clear_xattr_subsystem() also does not need to be executed again.
> So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
> to fix this UAF problem.
>
> Fixes: aa98d7cf59b5 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
> Cc: [email protected]
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Baokun Li <[email protected]>
> ---
> fs/jffs2/fs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
> index 2ac410477c4f..71f03a5d36ed 100644
> --- a/fs/jffs2/fs.c
> +++ b/fs/jffs2/fs.c
> @@ -603,8 +603,8 @@ int jffs2_do_fill_super(struct super_block *sb, struct fs_context *fc)
> jffs2_free_ino_caches(c);
> jffs2_free_raw_node_refs(c);
> kvfree(c->blocks);
> - out_inohash:
> jffs2_clear_xattr_subsystem(c);
> + out_inohash:
> kfree(c->inocache_list);
> out_wbuf:
> jffs2_flash_cleanup(c);
--
With Best Regards,
Baokun Li
----- Ursprüngliche Mail -----
> Von: "libaokun" <[email protected]>
> An: "richard" <[email protected]>, "David Woodhouse" <[email protected]>, "christian brauner"
> <[email protected]>, "linux-mtd" <[email protected]>, "linux-kernel"
> <[email protected]>
> CC: "yukuai3" <[email protected]>, "stable" <[email protected]>, "Hulk Robot" <[email protected]>, "libaokun"
> <[email protected]>
> Gesendet: Donnerstag, 10. März 2022 09:35:18
> Betreff: Re: [PATCH -next] jffs2: fix use-after-free in jffs2_clear_xattr_subsystem
> A gentle ping, sorry for the noise.
>
> 在 2021/12/28 20:54, Baokun Li 写道:
>> When we mount a jffs2 image, assume that the first few blocks of
>> the image are normal and contain at least one xattr-related inode,
>> but the next block is abnormal. As a result, an error is returned
>> in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
>> called in jffs2_build_filesystem() and then again in
>> jffs2_do_fill_super().
>>
>> Finally we can observe the following report:
>> ==================================================================
>> BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
>> Read of size 8 at addr ffff8881243384e0 by task mount/719
>>
>> Call Trace:
>> dump_stack+0x115/0x16b
>> jffs2_clear_xattr_subsystem+0x95/0x6ac
>> jffs2_do_fill_super+0x84f/0xc30
>> jffs2_fill_super+0x2ea/0x4c0
>> mtd_get_sb+0x254/0x400
>> mtd_get_sb_by_nr+0x4f/0xd0
>> get_tree_mtd+0x498/0x840
>> jffs2_get_tree+0x25/0x30
>> vfs_get_tree+0x8d/0x2e0
>> path_mount+0x50f/0x1e50
>> do_mount+0x107/0x130
>> __se_sys_mount+0x1c5/0x2f0
>> __x64_sys_mount+0xc7/0x160
>> do_syscall_64+0x45/0x70
>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>
>> Allocated by task 719:
>> kasan_save_stack+0x23/0x60
>> __kasan_kmalloc.constprop.0+0x10b/0x120
>> kasan_slab_alloc+0x12/0x20
>> kmem_cache_alloc+0x1c0/0x870
>> jffs2_alloc_xattr_ref+0x2f/0xa0
>> jffs2_scan_medium.cold+0x3713/0x4794
>> jffs2_do_mount_fs.cold+0xa7/0x2253
>> jffs2_do_fill_super+0x383/0xc30
>> jffs2_fill_super+0x2ea/0x4c0
>> [...]
>>
>> Freed by task 719:
>> kmem_cache_free+0xcc/0x7b0
>> jffs2_free_xattr_ref+0x78/0x98
>> jffs2_clear_xattr_subsystem+0xa1/0x6ac
>> jffs2_do_mount_fs.cold+0x5e6/0x2253
>> jffs2_do_fill_super+0x383/0xc30
>> jffs2_fill_super+0x2ea/0x4c0
>> [...]
>>
>> The buggy address belongs to the object at ffff8881243384b8
>> which belongs to the cache jffs2_xattr_ref of size 48
>> The buggy address is located 40 bytes inside of
>> 48-byte region [ffff8881243384b8, ffff8881243384e8)
>> [...]
>> ==================================================================
>>
>> The triggering of the BUG is shown in the following stack:
>> -----------------------------------------------------------
>> jffs2_fill_super
>> jffs2_do_fill_super
>> jffs2_do_mount_fs
>> jffs2_build_filesystem
>> jffs2_scan_medium
>> jffs2_scan_eraseblock <--- ERROR
>> jffs2_clear_xattr_subsystem <--- free
>> jffs2_clear_xattr_subsystem <--- free again
>> -----------------------------------------------------------
>>
>> An error is returned in jffs2_do_mount_fs(). If the error is returned
>> by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
>> be executed. If the error is returned by jffs2_build_filesystem(), the
>> jffs2_clear_xattr_subsystem() also does not need to be executed again.
>> So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
>> to fix this UAF problem.
>>
>> Fixes: aa98d7cf59b5 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
>> Cc: [email protected]
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: Baokun Li <[email protected]>
Applied. Thanks for fixing!
Thanks,
//richard
在 2022/3/17 6:01, Richard Weinberger 写道:
> ----- Ursprüngliche Mail -----
>> Von: "libaokun" <[email protected]>
>> An: "richard" <[email protected]>, "David Woodhouse" <[email protected]>, "christian brauner"
>> <[email protected]>, "linux-mtd" <[email protected]>, "linux-kernel"
>> <[email protected]>
>> CC: "yukuai3" <[email protected]>, "stable" <[email protected]>, "Hulk Robot" <[email protected]>, "libaokun"
>> <[email protected]>
>> Gesendet: Donnerstag, 10. März 2022 09:35:18
>> Betreff: Re: [PATCH -next] jffs2: fix use-after-free in jffs2_clear_xattr_subsystem
>> A gentle ping, sorry for the noise.
>>
>> 在 2021/12/28 20:54, Baokun Li 写道:
>>> When we mount a jffs2 image, assume that the first few blocks of
>>> the image are normal and contain at least one xattr-related inode,
>>> but the next block is abnormal. As a result, an error is returned
>>> in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
>>> called in jffs2_build_filesystem() and then again in
>>> jffs2_do_fill_super().
>>>
>>> Finally we can observe the following report:
>>> ==================================================================
>>> BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
>>> Read of size 8 at addr ffff8881243384e0 by task mount/719
>>>
>>> Call Trace:
>>> dump_stack+0x115/0x16b
>>> jffs2_clear_xattr_subsystem+0x95/0x6ac
>>> jffs2_do_fill_super+0x84f/0xc30
>>> jffs2_fill_super+0x2ea/0x4c0
>>> mtd_get_sb+0x254/0x400
>>> mtd_get_sb_by_nr+0x4f/0xd0
>>> get_tree_mtd+0x498/0x840
>>> jffs2_get_tree+0x25/0x30
>>> vfs_get_tree+0x8d/0x2e0
>>> path_mount+0x50f/0x1e50
>>> do_mount+0x107/0x130
>>> __se_sys_mount+0x1c5/0x2f0
>>> __x64_sys_mount+0xc7/0x160
>>> do_syscall_64+0x45/0x70
>>> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>>
>>> Allocated by task 719:
>>> kasan_save_stack+0x23/0x60
>>> __kasan_kmalloc.constprop.0+0x10b/0x120
>>> kasan_slab_alloc+0x12/0x20
>>> kmem_cache_alloc+0x1c0/0x870
>>> jffs2_alloc_xattr_ref+0x2f/0xa0
>>> jffs2_scan_medium.cold+0x3713/0x4794
>>> jffs2_do_mount_fs.cold+0xa7/0x2253
>>> jffs2_do_fill_super+0x383/0xc30
>>> jffs2_fill_super+0x2ea/0x4c0
>>> [...]
>>>
>>> Freed by task 719:
>>> kmem_cache_free+0xcc/0x7b0
>>> jffs2_free_xattr_ref+0x78/0x98
>>> jffs2_clear_xattr_subsystem+0xa1/0x6ac
>>> jffs2_do_mount_fs.cold+0x5e6/0x2253
>>> jffs2_do_fill_super+0x383/0xc30
>>> jffs2_fill_super+0x2ea/0x4c0
>>> [...]
>>>
>>> The buggy address belongs to the object at ffff8881243384b8
>>> which belongs to the cache jffs2_xattr_ref of size 48
>>> The buggy address is located 40 bytes inside of
>>> 48-byte region [ffff8881243384b8, ffff8881243384e8)
>>> [...]
>>> ==================================================================
>>>
>>> The triggering of the BUG is shown in the following stack:
>>> -----------------------------------------------------------
>>> jffs2_fill_super
>>> jffs2_do_fill_super
>>> jffs2_do_mount_fs
>>> jffs2_build_filesystem
>>> jffs2_scan_medium
>>> jffs2_scan_eraseblock <--- ERROR
>>> jffs2_clear_xattr_subsystem <--- free
>>> jffs2_clear_xattr_subsystem <--- free again
>>> -----------------------------------------------------------
>>>
>>> An error is returned in jffs2_do_mount_fs(). If the error is returned
>>> by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
>>> be executed. If the error is returned by jffs2_build_filesystem(), the
>>> jffs2_clear_xattr_subsystem() also does not need to be executed again.
>>> So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
>>> to fix this UAF problem.
>>>
>>> Fixes: aa98d7cf59b5 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
>>> Cc: [email protected]
>>> Reported-by: Hulk Robot <[email protected]>
>>> Signed-off-by: Baokun Li <[email protected]>
> Applied. Thanks for fixing!
>
> Thanks,
> //richard
> .
Thank you for your review!
--
With Best Regards,
Baokun Li