From: ZhangPeng <[email protected]>
Syzbot reported a OOB Write bug:
loop0: detected capacity change from 0 to 64
==================================================================
BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
fs/hfs/trans.c:133
Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:284
print_report+0x107/0x1f0 mm/kasan/report.c:395
kasan_report+0xcd/0x100 mm/kasan/report.c:495
hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
lookup_open fs/namei.c:3391 [inline]
open_last_lookups fs/namei.c:3481 [inline]
path_openat+0x10e6/0x2df0 fs/namei.c:3710
do_filp_open+0x264/0x4f0 fs/namei.c:3740
If in->len is much larger than HFS_NAMELEN(31) which is the maximum
length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
that case, when the dst reaches the boundary, the srclen is still
greater than 0, which causes a OOB Write.
Fix this by adding a Check on dstlen before Writing to dst address.
Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
Reported-by: [email protected]
Signed-off-by: ZhangPeng <[email protected]>
---
fs/hfs/trans.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
index 39f5e343bf4d..886158db07b3 100644
--- a/fs/hfs/trans.c
+++ b/fs/hfs/trans.c
@@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
dst += size;
dstlen -= size;
} else {
+ if (dstlen == 0)
+ goto out;
*dst++ = ch > 0xff ? '?' : ch;
dstlen--;
}
--
2.25.1
> On Nov 25, 2022, at 8:36 PM, Peng Zhang <[email protected]> wrote:
>
> From: ZhangPeng <[email protected]>
>
> Syzbot reported a OOB Write bug:
>
> loop0: detected capacity change from 0 to 64
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
> fs/hfs/trans.c:133
> Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
>
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
> print_address_description+0x74/0x340 mm/kasan/report.c:284
> print_report+0x107/0x1f0 mm/kasan/report.c:395
> kasan_report+0xcd/0x100 mm/kasan/report.c:495
> hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
> hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
> hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
> lookup_open fs/namei.c:3391 [inline]
> open_last_lookups fs/namei.c:3481 [inline]
> path_openat+0x10e6/0x2df0 fs/namei.c:3710
> do_filp_open+0x264/0x4f0 fs/namei.c:3740
>
> If in->len is much larger than HFS_NAMELEN(31) which is the maximum
> length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
> that case, when the dst reaches the boundary, the srclen is still
> greater than 0, which causes a OOB Write.
> Fix this by adding a Check on dstlen before Writing to dst address.
>
> Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
> Reported-by: [email protected]
> Signed-off-by: ZhangPeng <[email protected]>
> ---
> fs/hfs/trans.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
> index 39f5e343bf4d..886158db07b3 100644
> --- a/fs/hfs/trans.c
> +++ b/fs/hfs/trans.c
> @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
> dst += size;
> dstlen -= size;
> } else {
> + if (dstlen == 0)
> + goto out;
Maybe, it makes sense to use dstlen instead of srclen in while()?
We have now:
while (srclen > 0) {
<skipped>
} else {
<skipped>
}
We can use instead:
while (dstlen > 0) {
<skipped>
} else {
<skipped>
}
Will it fix the issue?
Thanks,
Slava.
> *dst++ = ch > 0xff ? '?' : ch;
> dstlen--;
> }
> --
> 2.25.1
>
On 2022/11/29 3:29, Viacheslav Dubeyko wrote:
>> On Nov 25, 2022, at 8:36 PM, Peng Zhang <[email protected]> wrote:
>>
>> From: ZhangPeng <[email protected]>
>>
>> Syzbot reported a OOB Write bug:
>>
>> loop0: detected capacity change from 0 to 64
>> ==================================================================
>> BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
>> fs/hfs/trans.c:133
>> Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
>>
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:88 [inline]
>> dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>> print_address_description+0x74/0x340 mm/kasan/report.c:284
>> print_report+0x107/0x1f0 mm/kasan/report.c:395
>> kasan_report+0xcd/0x100 mm/kasan/report.c:495
>> hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
>> hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
>> hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
>> lookup_open fs/namei.c:3391 [inline]
>> open_last_lookups fs/namei.c:3481 [inline]
>> path_openat+0x10e6/0x2df0 fs/namei.c:3710
>> do_filp_open+0x264/0x4f0 fs/namei.c:3740
>>
>> If in->len is much larger than HFS_NAMELEN(31) which is the maximum
>> length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
>> that case, when the dst reaches the boundary, the srclen is still
>> greater than 0, which causes a OOB Write.
>> Fix this by adding a Check on dstlen before Writing to dst address.
>>
>> Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
>> Reported-by: [email protected]
>> Signed-off-by: ZhangPeng <[email protected]>
>> ---
>> fs/hfs/trans.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
>> index 39f5e343bf4d..886158db07b3 100644
>> --- a/fs/hfs/trans.c
>> +++ b/fs/hfs/trans.c
>> @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
>> dst += size;
>> dstlen -= size;
>> } else {
>> + if (dstlen == 0)
>> + goto out;
> Maybe, it makes sense to use dstlen instead of srclen in while()?
>
> We have now:
>
> while (srclen > 0) {
> <skipped>
> } else {
> <skipped>
> }
>
> We can use instead:
>
> while (dstlen > 0) {
> <skipped>
> } else {
> <skipped>
> }
>
> Will it fix the issue?
>
> Thanks,
> Slava.
Thank you for your help.
After testing, it fix the issue.
Would it be better to add dstlen > 0 instead of replacing srclen > 0 with dstlen > 0?
Because there may be dstlen > 0 and srclen <= 0.
we can use:
while (srclen > 0 && dstlen > 0) {
<skipped>
} else {
<skipped>
}
Thanks,
Zhang Peng
>> *dst++ = ch > 0xff ? '?' : ch;
>> dstlen--;
>> }
>> --
>> 2.25.1
>>
>
> On Nov 28, 2022, at 6:23 PM, zhangpeng (AS) <[email protected]> wrote:
>
> On 2022/11/29 3:29, Viacheslav Dubeyko wrote:
>
>>> On Nov 25, 2022, at 8:36 PM, Peng Zhang <[email protected]> wrote:
>>>
>>> From: ZhangPeng <[email protected]>
>>>
>>> Syzbot reported a OOB Write bug:
>>>
>>> loop0: detected capacity change from 0 to 64
>>> ==================================================================
>>> BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
>>> fs/hfs/trans.c:133
>>> Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
>>>
>>> Call Trace:
>>> <TASK>
>>> __dump_stack lib/dump_stack.c:88 [inline]
>>> dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>>> print_address_description+0x74/0x340 mm/kasan/report.c:284
>>> print_report+0x107/0x1f0 mm/kasan/report.c:395
>>> kasan_report+0xcd/0x100 mm/kasan/report.c:495
>>> hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
>>> hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
>>> hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
>>> lookup_open fs/namei.c:3391 [inline]
>>> open_last_lookups fs/namei.c:3481 [inline]
>>> path_openat+0x10e6/0x2df0 fs/namei.c:3710
>>> do_filp_open+0x264/0x4f0 fs/namei.c:3740
>>>
>>> If in->len is much larger than HFS_NAMELEN(31) which is the maximum
>>> length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
>>> that case, when the dst reaches the boundary, the srclen is still
>>> greater than 0, which causes a OOB Write.
>>> Fix this by adding a Check on dstlen before Writing to dst address.
>>>
>>> Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
>>> Reported-by: [email protected]
>>> Signed-off-by: ZhangPeng <[email protected]>
>>> ---
>>> fs/hfs/trans.c | 2 ++
>>> 1 file changed, 2 insertions(+)
>>>
>>> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
>>> index 39f5e343bf4d..886158db07b3 100644
>>> --- a/fs/hfs/trans.c
>>> +++ b/fs/hfs/trans.c
>>> @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
>>> dst += size;
>>> dstlen -= size;
>>> } else {
>>> + if (dstlen == 0)
>>> + goto out;
>> Maybe, it makes sense to use dstlen instead of srclen in while()?
>>
>> We have now:
>>
>> while (srclen > 0) {
>> <skipped>
>> } else {
>> <skipped>
>> }
>>
>> We can use instead:
>>
>> while (dstlen > 0) {
>> <skipped>
>> } else {
>> <skipped>
>> }
>>
>> Will it fix the issue?
>>
>> Thanks,
>> Slava.
>
> Thank you for your help.
>
> After testing, it fix the issue.
> Would it be better to add dstlen > 0 instead of replacing srclen > 0 with dstlen > 0?
> Because there may be dstlen > 0 and srclen <= 0.
>
> we can use:
>
> while (srclen > 0 && dstlen > 0) {
> <skipped>
> } else {
> <skipped>
> }
>
Looks good to me.
Thanks,
Slava.
>
> Thanks,
> Zhang Peng
>
>>> *dst++ = ch > 0xff ? '?' : ch;
>>> dstlen--;
>>> }
>>> --
>>> 2.25.1
On 2022/11/30 3:08, Viacheslav Dubeyko wrote:
>> On Nov 28, 2022, at 6:23 PM, zhangpeng (AS) <[email protected]> wrote:
>>
>> On 2022/11/29 3:29, Viacheslav Dubeyko wrote:
>>>> On Nov 25, 2022, at 8:36 PM, Peng Zhang <[email protected]> wrote:
>>>>
>>>> From: ZhangPeng <[email protected]>
>>>>
>>>> Syzbot reported a OOB Write bug:
>>>>
>>>> loop0: detected capacity change from 0 to 64
>>>> ==================================================================
>>>> BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
>>>> fs/hfs/trans.c:133
>>>> Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
>>>>
>>>> Call Trace:
>>>> <TASK>
>>>> __dump_stack lib/dump_stack.c:88 [inline]
>>>> dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>>>> print_address_description+0x74/0x340 mm/kasan/report.c:284
>>>> print_report+0x107/0x1f0 mm/kasan/report.c:395
>>>> kasan_report+0xcd/0x100 mm/kasan/report.c:495
>>>> hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
>>>> hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
>>>> hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
>>>> lookup_open fs/namei.c:3391 [inline]
>>>> open_last_lookups fs/namei.c:3481 [inline]
>>>> path_openat+0x10e6/0x2df0 fs/namei.c:3710
>>>> do_filp_open+0x264/0x4f0 fs/namei.c:3740
>>>>
>>>> If in->len is much larger than HFS_NAMELEN(31) which is the maximum
>>>> length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
>>>> that case, when the dst reaches the boundary, the srclen is still
>>>> greater than 0, which causes a OOB Write.
>>>> Fix this by adding a Check on dstlen before Writing to dst address.
>>>>
>>>> Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
>>>> Reported-by: [email protected]
>>>> Signed-off-by: ZhangPeng <[email protected]>
>>>> ---
>>>> fs/hfs/trans.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
>>>> index 39f5e343bf4d..886158db07b3 100644
>>>> --- a/fs/hfs/trans.c
>>>> +++ b/fs/hfs/trans.c
>>>> @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
>>>> dst += size;
>>>> dstlen -= size;
>>>> } else {
>>>> + if (dstlen == 0)
>>>> + goto out;
>>> Maybe, it makes sense to use dstlen instead of srclen in while()?
>>>
>>> We have now:
>>>
>>> while (srclen > 0) {
>>> <skipped>
>>> } else {
>>> <skipped>
>>> }
>>>
>>> We can use instead:
>>>
>>> while (dstlen > 0) {
>>> <skipped>
>>> } else {
>>> <skipped>
>>> }
>>>
>>> Will it fix the issue?
>>>
>>> Thanks,
>>> Slava.
>> Thank you for your help.
>>
>> After testing, it fix the issue.
>> Would it be better to add dstlen > 0 instead of replacing srclen > 0 with dstlen > 0?
>> Because there may be dstlen > 0 and srclen <= 0.
>>
>> we can use:
>>
>> while (srclen > 0 && dstlen > 0) {
>> <skipped>
>> } else {
>> <skipped>
>> }
>>
> Looks good to me.
Can I put you down as a Reviewed-by or Suggested-by?
Thanks,
Zhang Peng
> Thanks,
> Slava.
>
>> Thanks,
>> Zhang Peng
>>
>>>> *dst++ = ch > 0xff ? '?' : ch;
>>>> dstlen--;
>>>> }
>>>> --
>>>> 2.25.1
> On Nov 30, 2022, at 5:53 PM, zhangpeng (AS) <[email protected]> wrote:
>
>
> On 2022/11/30 3:08, Viacheslav Dubeyko wrote:
>>> On Nov 28, 2022, at 6:23 PM, zhangpeng (AS) <[email protected]> wrote:
>>>
>>> On 2022/11/29 3:29, Viacheslav Dubeyko wrote:
>>>>> On Nov 25, 2022, at 8:36 PM, Peng Zhang <[email protected]> wrote:
>>>>>
>>>>> From: ZhangPeng <[email protected]>
>>>>>
>>>>> Syzbot reported a OOB Write bug:
>>>>>
>>>>> loop0: detected capacity change from 0 to 64
>>>>> ==================================================================
>>>>> BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0
>>>>> fs/hfs/trans.c:133
>>>>> Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
>>>>>
>>>>> Call Trace:
>>>>> <TASK>
>>>>> __dump_stack lib/dump_stack.c:88 [inline]
>>>>> dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>>>>> print_address_description+0x74/0x340 mm/kasan/report.c:284
>>>>> print_report+0x107/0x1f0 mm/kasan/report.c:395
>>>>> kasan_report+0xcd/0x100 mm/kasan/report.c:495
>>>>> hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133
>>>>> hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28
>>>>> hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31
>>>>> lookup_open fs/namei.c:3391 [inline]
>>>>> open_last_lookups fs/namei.c:3481 [inline]
>>>>> path_openat+0x10e6/0x2df0 fs/namei.c:3710
>>>>> do_filp_open+0x264/0x4f0 fs/namei.c:3740
>>>>>
>>>>> If in->len is much larger than HFS_NAMELEN(31) which is the maximum
>>>>> length of an HFS filename, a OOB Write could occur in hfs_asc2mac(). In
>>>>> that case, when the dst reaches the boundary, the srclen is still
>>>>> greater than 0, which causes a OOB Write.
>>>>> Fix this by adding a Check on dstlen before Writing to dst address.
>>>>>
>>>>> Fixes: 328b92278650 ("[PATCH] hfs: NLS support")
>>>>> Reported-by: [email protected]
>>>>> Signed-off-by: ZhangPeng <[email protected]>
>>>>> ---
>>>>> fs/hfs/trans.c | 2 ++
>>>>> 1 file changed, 2 insertions(+)
>>>>>
>>>>> diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c
>>>>> index 39f5e343bf4d..886158db07b3 100644
>>>>> --- a/fs/hfs/trans.c
>>>>> +++ b/fs/hfs/trans.c
>>>>> @@ -130,6 +130,8 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr
>>>>> dst += size;
>>>>> dstlen -= size;
>>>>> } else {
>>>>> + if (dstlen == 0)
>>>>> + goto out;
>>>> Maybe, it makes sense to use dstlen instead of srclen in while()?
>>>>
>>>> We have now:
>>>>
>>>> while (srclen > 0) {
>>>> <skipped>
>>>> } else {
>>>> <skipped>
>>>> }
>>>>
>>>> We can use instead:
>>>>
>>>> while (dstlen > 0) {
>>>> <skipped>
>>>> } else {
>>>> <skipped>
>>>> }
>>>>
>>>> Will it fix the issue?
>>>>
>>>> Thanks,
>>>> Slava.
>>> Thank you for your help.
>>>
>>> After testing, it fix the issue.
>>> Would it be better to add dstlen > 0 instead of replacing srclen > 0 with dstlen > 0?
>>> Because there may be dstlen > 0 and srclen <= 0.
>>>
>>> we can use:
>>>
>>> while (srclen > 0 && dstlen > 0) {
>>> <skipped>
>>> } else {
>>> <skipped>
>>> }
>>>
>> Looks good to me.
>
> Can I put you down as a Reviewed-by or Suggested-by?
Sure. I hope to see the second version of the patch.
Reviewed-by: Viacheslav Dubeyko <[email protected]>
Thanks,
Slava.
>
> Thanks,
> Zhang Peng
>
>> Thanks,
>> Slava.
>>
>>> Thanks,
>>> Zhang Peng
>>>
>>>>> *dst++ = ch > 0xff ? '?' : ch;
>>>>> dstlen--;
>>>>> }
>>>>> --
>>>>> 2.25.1