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: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 8 Jun 2022 09:09:55 +0200
From:   Krzysztof Kozlowski <>
To:     Martin Faltesek <>,
Subject: Re: [PATCH net v3 3/3] nfc: st21nfca: fix incorrect sizing
 calculations in EVT_TRANSACTION

On 07/06/2022 04:57, Martin Faltesek wrote:
> The transaction buffer is allocated by using the size of the packet buf,
> and subtracting two which seem intended to remove the two tags which are
> not present in the target structure. This calculation leads to under
> counting memory because of differences between the packet contents and the
> target structure. The aid_len field is a u8 in the packet, but a u32 in
> the structure, resulting in at least 3 bytes always being under counted.
> Further, the aid data is a variable length field in the packet, but fixed
> in the structure, so if this field is less than the max, the difference is
> added to the under counting.
> The last validation check for transaction->params_len is also incorrect
> since it employs the same accounting error.
> To fix, perform validation checks progressively to safely reach the
> next field, to determine the size of both buffers and verify both tags.
> Once all validation checks pass, allocate the buffer and copy the data.
> This eliminates freeing memory on the error path, as those checks are
> moved ahead of memory allocation.
> Fixes: 26fc6c7f02cb ("NFC: st21nfca: Add HCI transaction event support")
> Fixes: 4fbcc1a4cb20 ("nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION")
> Cc:
> Signed-off-by: Martin Faltesek <>
> ---

Reviewed-by: Krzysztof Kozlowski <>

Best regards,

Powered by blists - more mailing lists