CVE-2023-54039

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access<br /> <br /> In the j1939_tp_tx_dat_new() function, an out-of-bounds memory access<br /> could occur during the memcpy() operation if the size of skb-&gt;cb is<br /> larger than the size of struct j1939_sk_buff_cb. This is because the<br /> memcpy() operation uses the size of skb-&gt;cb, leading to a read beyond<br /> the struct j1939_sk_buff_cb.<br /> <br /> Updated the memcpy() operation to use the size of struct<br /> j1939_sk_buff_cb instead of the size of skb-&gt;cb. This ensures that the<br /> memcpy() operation only reads the memory within the bounds of struct<br /> j1939_sk_buff_cb, preventing out-of-bounds memory access.<br /> <br /> Additionally, add a BUILD_BUG_ON() to check that the size of skb-&gt;cb<br /> is greater than or equal to the size of struct j1939_sk_buff_cb. This<br /> ensures that the skb-&gt;cb buffer is large enough to hold the<br /> j1939_sk_buff_cb structure.<br /> <br /> [mkl: rephrase commit message]