CVE-2024-35901

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 buffers 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: [ 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] [ 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.

Affected Software

References

• https://git.kernel.org/stable/c/05cb7c41fa1a7a7b2c2a6b81bbe7c67f5c11932b
• https://git.kernel.org/stable/c/c0de6ab920aafb56feab56058e46b688e694a246
• https://git.kernel.org/stable/c/ca58927b00385005f488b6a9905ced7a4f719aad