can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access
In the j1939_tp_tx_dat_new() function, an out-of-bounds memory access could occur during the memcpy() operation if the size of skb->cb is larger than the size of struct j1939_sk_buff_cb. This is because the memcpy() operation uses the size of skb->cb, leading to a read beyond the struct j1939_sk_buff_cb. Updated the memcpy() operation to use the size of struct j1939_sk_buff_cb instead of the size of skb->cb. This ensures that the memcpy() operation only reads the memory within the bounds of struct j1939_sk_buff_cb, preventing out-of-bounds memory access. Additionally, add a BUILD_BUG_ON() to check that the size of skb->cb is greater than or equal to the size of struct j1939_sk_buff_cb. This ensures that the skb->cb buffer is large enough to hold the j1939_sk_buff_cb structure. Fixes: 9d71dd0c ("can: add support of SAE J1939 protocol") Reported-by:Shuangpeng Bai <sjb7183@psu.edu> Tested-by:
Shuangpeng Bai <sjb7183@psu.edu> Signed-off-by:
Oleksij Rempel <o.rempel@pengutronix.de> Link: https://groups.google.com/g/syzkaller/c/G_LL-C3plRs/m/-8xCi6dCAgAJ Link: https://lore.kernel.org/all/20230404073128.3173900-1-o.rempel@pengutronix.de Cc: stable@vger.kernel.org [mkl: rephrase commit message] Signed-off-by:
Marc Kleine-Budde <mkl@pengutronix.de>
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