In the Linux kernel, the following vulnerability has been resolved: net: mana: Fix Rx DMA datasize and skb_over_panic mana_get_rxbuf_cfg() aligns the RX buffer's DMA datasize to be multiple of 64. So a packet slightly bigger than mtu+14, say 1536, can be received and cause skb_over_panic. Sample dmesg: [ 5325.237162] skbuff: skb_over_panic: text:ffffffffc043277a len:1536 put:1536 head:ff1100018b517000 data:ff1100018b517100 tail:0x700 end:0x6ea dev:<NULL> [ 5325.243689] ------------[ cut here ]------------ [ 5325.245748] kernel BUG at net/core/skbuff.c:192! [ 5325.247838] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 5325.258374] RIP: 0010:skb_panic+0x4f/0x60 [ 5325.302941] Call Trace: [ 5325.304389] <IRQ> [ 5325.315794] ? skb_panic+0x4f/0x60 [ 5325.317457] ? asm_exc_invalid_op+0x1f/0x30 [ 5325.319490] ? skb_panic+0x4f/0x60 [ 5325.321161] skb_put+0x4e/0x50 [ 5325.322670] mana_poll+0x6fa/0xb50 [mana] [ 5325.324578] __napi_poll+0x33/0x1e0 [ 5325.326328] net_rx_action+0x12e/0x280 As discussed internally, this alignment is not necessary. To fix this bug, remove it from the code. So oversized packets will be marked as CQE_RX_TRUNCATED by NIC, and dropped.
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