linux/drivers/nfc/st21nfca
Martin Faltesek f2e19b3659 nfc: st21nfca: fix incorrect sizing calculations in EVT_TRANSACTION
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: 26fc6c7f02 ("NFC: st21nfca: Add HCI transaction event support")
Fixes: 4fbcc1a4cb ("nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Faltesek <mfaltesek@google.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-08 10:17:17 -07:00
..
core.c nfc: st21nfca: remove unused header includes 2021-08-26 09:13:36 +01:00
dep.c NFC: st21nfca: remove unnecessary variable and labels 2021-05-20 15:44:27 -07:00
i2c.c nfc: st21nfca: remove unnecessary skb check before kfree_skb() 2022-03-18 21:41:51 -07:00
Kconfig
Makefile
se.c nfc: st21nfca: fix incorrect sizing calculations in EVT_TRANSACTION 2022-06-08 10:17:17 -07:00
st21nfca.h NFC: hci: fix sleep in atomic context bugs in nfc_hci_hcp_message_tx 2022-05-19 17:54:02 -07:00
vendor_cmds.c nfc: use *_set_vendor_cmds() helpers 2022-01-27 13:53:26 +00:00