linux-kernel - Re: [PATCH] drivers: pci: Fix flexible array usage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <93cb6da2-5bba-4574-88dc-1f3d03a9b8b9@gmail.com>
Date: Thu, 13 Feb 2025 16:07:22 +0530
From: Purva Yeshi <purvayeshi550@...il.com>
To: Keith Busch <kbusch@...nel.org>
Cc: bhelgaas@...gle.com, skhan@...uxfoundation.org,
 linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drivers: pci: Fix flexible array usage

On 11/02/25 04:33, Keith Busch wrote:
> On Mon, Feb 10, 2025 at 06:57:40PM +0530, Purva Yeshi wrote:
>> Fix warning detected by smatch tool:
>> Array of flexible structure occurs in 'pci_saved_state' struct
>>
>> The warning occurs because struct pci_saved_state contains struct
>> pci_cap_saved_data cap[], where cap[] has a flexible array member (data[]).
>> Arrays of structures with flexible members are not allowed, leading to this
>> warning.
>>
>> Replaced cap[] with a pointer (*cap), allowing dynamic memory allocation
>> instead of embedding an invalid array of flexible structures.
>>
>> Signed-off-by: Purva Yeshi <purvayeshi550@...il.com>
>> ---
>>   drivers/pci/pci.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index 869d204a7..648a080ef 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -1929,7 +1929,7 @@ EXPORT_SYMBOL(pci_restore_state);
>>   
>>   struct pci_saved_state {
>>   	u32 config_space[16];
>> -	struct pci_cap_saved_data cap[];
>> +	struct pci_cap_saved_data *cap;
>>   };
> 
> I don't think this is right. Previously the space for "cap" was
> allocated at the end of the pci_saved_state, but now it's just an
> uninitialized pointer.

Thanks for your feedback. I understand your concern about the 
uninitialized pointer. To verify this, I tested the file using 
'~/smatch/smatch_scripts/kchecker drivers/pci/pci.c' smatch command, and 
it did not report any errors indicating that cap was uninitialized. 
Based on this, I initially believed the change to be safe.