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[PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target

Anup Sharma posted 1 patch 2 years, 8 months ago 
net/nfc/nci/core.c | 5 +++++
1 file changed, 5 insertions(+)
[PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target
Posted by Anup Sharma 2 years, 8 months ago 
syzbot found  UBSAN: shift-out-of-bounds in nci_activate_target [1],
when nci_target->supported_protocols is bigger than UNIT_MAX,
where supported_protocols is unsigned 32-bit interger type.

32 is the maximum allowed for supported_protocols. Added a check
for it. 

[1] UBSAN: shift-out-of-bounds in net/nfc/nci/core.c:912:45
shift exponent 4294967071 is too large for 32-bit type 'int'
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
 nci_activate_target.cold+0x1a/0x1f net/nfc/nci/core.c:912
 nfc_activate_target+0x1f8/0x4c0 net/nfc/core.c:420
 nfc_genl_activate_target+0x1f3/0x290 net/nfc/netlink.c:900
 genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
 genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]

Reported-by: syzbot+0839b78e119aae1fec78@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433

Signed-off-by: anupsharma <anupnewsmail@gmail.com>
---
 net/nfc/nci/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index fff755dde30d..e9d968bd1cd9 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -908,6 +908,11 @@ static int nci_activate_target(struct nfc_dev *nfc_dev,
 		pr_err("unable to find the selected target\n");
 		return -EINVAL;
 	}
+	
+	if (nci_target->supported_protocols >= 32) {
+		pr_err("Too many supported protocol by the device\n");
+		return -EINVAL;
+	}
 
 	if (!(nci_target->supported_protocols & (1 << protocol))) {
 		pr_err("target does not support the requested protocol 0x%x\n",
-- 
2.34.1
Re: [PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target
Posted by Krzysztof Kozlowski 2 years, 8 months ago 
On 19/04/2023 03:16, Anup Sharma wrote:
> syzbot found  UBSAN: shift-out-of-bounds in nci_activate_target [1],
> when nci_target->supported_protocols is bigger than UNIT_MAX,
> where supported_protocols is unsigned 32-bit interger type.
> 
> 32 is the maximum allowed for supported_protocols. Added a check
> for it. 
> 
> [1] UBSAN: shift-out-of-bounds in net/nfc/nci/core.c:912:45
> shift exponent 4294967071 is too large for 32-bit type 'int'
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
>  ubsan_epilogue lib/ubsan.c:217 [inline]
>  __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
>  nci_activate_target.cold+0x1a/0x1f net/nfc/nci/core.c:912
>  nfc_activate_target+0x1f8/0x4c0 net/nfc/core.c:420
>  nfc_genl_activate_target+0x1f3/0x290 net/nfc/netlink.c:900
>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
> 
> Reported-by: syzbot+0839b78e119aae1fec78@syzkaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433
> 
> Signed-off-by: anupsharma <anupnewsmail@gmail.com>

Also, no blank lines between tags.

Best regards,
Krzysztof
Re: [PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target
Posted by Krzysztof Kozlowski 2 years, 8 months ago 
On 19/04/2023 03:16, Anup Sharma wrote:
> syzbot found  UBSAN: shift-out-of-bounds in nci_activate_target [1],
> when nci_target->supported_protocols is bigger than UNIT_MAX,

UINT_MAX?

> where supported_protocols is unsigned 32-bit interger type.

integer?

> 
> 32 is the maximum allowed for supported_protocols. Added a check
> for it. 
> 
> [1] UBSAN: shift-out-of-bounds in net/nfc/nci/core.c:912:45
> shift exponent 4294967071 is too large for 32-bit type 'int'
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
>  ubsan_epilogue lib/ubsan.c:217 [inline]
>  __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
>  nci_activate_target.cold+0x1a/0x1f net/nfc/nci/core.c:912
>  nfc_activate_target+0x1f8/0x4c0 net/nfc/core.c:420
>  nfc_genl_activate_target+0x1f3/0x290 net/nfc/netlink.c:900
>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
> 
> Reported-by: syzbot+0839b78e119aae1fec78@syzkaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433
> 
> Signed-off-by: anupsharma <anupnewsmail@gmail.com>
> ---
>  net/nfc/nci/core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
> index fff755dde30d..e9d968bd1cd9 100644
> --- a/net/nfc/nci/core.c
> +++ b/net/nfc/nci/core.c
> @@ -908,6 +908,11 @@ static int nci_activate_target(struct nfc_dev *nfc_dev,
>  		pr_err("unable to find the selected target\n");
>  		return -EINVAL;
>  	}
> +	
> +	if (nci_target->supported_protocols >= 32) {

I don't think it makes any sense. How do you protect from UBSAN reported
shift? Why supported_protocols cannot be 33? You are not shifting the
supported_protocols...

> +		pr_err("Too many supported protocol by the device\n");
> +		return -EINVAL;

I am pretty sure that you broke now NFC. Test the patches first and
share your test scenario.

> +	}
>  
>  	if (!(nci_target->supported_protocols & (1 << protocol))) {



Best regards,
Krzysztof
Re: [PATCH] net: nfc: nci: fix for UBSAN: shift-out-of-bounds in nci_activate_target
Posted by Krzysztof Kozlowski 2 years, 8 months ago 
On 19/04/2023 10:26, Krzysztof Kozlowski wrote:
> On 19/04/2023 03:16, Anup Sharma wrote:
>> syzbot found  UBSAN: shift-out-of-bounds in nci_activate_target [1],
>> when nci_target->supported_protocols is bigger than UNIT_MAX,
> 
> UINT_MAX?
> 
>> where supported_protocols is unsigned 32-bit interger type.
> 
> integer?
> 
>>
>> 32 is the maximum allowed for supported_protocols. Added a check
>> for it. 
>>
>> [1] UBSAN: shift-out-of-bounds in net/nfc/nci/core.c:912:45
>> shift exponent 4294967071 is too large for 32-bit type 'int'
>> Call Trace:
>>  <TASK>
>>  __dump_stack lib/dump_stack.c:88 [inline]
>>  dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
>>  ubsan_epilogue lib/ubsan.c:217 [inline]
>>  __ubsan_handle_shift_out_of_bounds+0x221/0x5a0 lib/ubsan.c:387
>>  nci_activate_target.cold+0x1a/0x1f net/nfc/nci/core.c:912
>>  nfc_activate_target+0x1f8/0x4c0 net/nfc/core.c:420
>>  nfc_genl_activate_target+0x1f3/0x290 net/nfc/netlink.c:900
>>  genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968
>>  genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]
>>
>> Reported-by: syzbot+0839b78e119aae1fec78@syzkaller.appspotmail.com
>> Link: https://syzkaller.appspot.com/bug?id=19cf2724120ef8c51c8d2566df0cc34617188433
>>
>> Signed-off-by: anupsharma <anupnewsmail@gmail.com>
>> ---
>>  net/nfc/nci/core.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
>> index fff755dde30d..e9d968bd1cd9 100644
>> --- a/net/nfc/nci/core.c
>> +++ b/net/nfc/nci/core.c
>> @@ -908,6 +908,11 @@ static int nci_activate_target(struct nfc_dev *nfc_dev,
>>  		pr_err("unable to find the selected target\n");
>>  		return -EINVAL;
>>  	}
>> +	
>> +	if (nci_target->supported_protocols >= 32) {
> 
> I don't think it makes any sense. How do you protect from UBSAN reported
> shift? Why supported_protocols cannot be 33? You are not shifting the
> supported_protocols...
> 
>> +		pr_err("Too many supported protocol by the device\n");
>> +		return -EINVAL;
> 
> I am pretty sure that you broke now NFC. Test the patches first and
> share your test scenario.

BTW, ISO15693 is here protocol 128, so definitely more than 32.

Best regards,
Krzysztof

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