Описание
In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: restore NET_IP_ALIGN in the RX DMA offset
Since the RX path was converted to zero-copy, the page pool page is handed to the stack directly as the skb head, and the offset the DMA engine writes at is what determines the alignment of the packet headers.
Before the conversion the payload was copied into an skb obtained from napi_alloc_skb(), which reserves NET_SKB_PAD + NET_IP_ALIGN. The conversion moved the headroom into stmmac_rx_offset() but did not carry over NET_IP_ALIGN, so on architectures where NET_IP_ALIGN is 2 the IP header now lands misaligned:
64 (NET_SKB_PAD) + 14 (ethernet) + 20 (IP) = 98
Same for the XDP branch:
256 (XDP_PACKET_HEADROOM) + 14 (ethernet) + 20 (IP) = 290
On ARM32 this is fatal, because ldm and ldrd trap on unaligned addresses even when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set.
Any received echo request panics the machine, e.g:
Unhandled fault: alignment except
EPSS
7.5 High
CVSS3
Дефекты
Связанные уязвимости
(In the Linux kernel, the following vulnerability has been resolved: n ...)
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: net: stmmac: restore NET_IP_ALIGN in the RX DMA offset Since the RX path was converted to zero-copy, the page pool page is handed to the stack directly as the skb head, and the offset the DMA engine writes at is what determines the alignment of the packet headers. Before the conversion the payload was copied into an skb obtained from napi_alloc_skb(), which reserves NET_SKB_PAD + NET_IP_ALIGN. The conversion moved the headroom into stmmac_rx_offset() but did not carry over NET_IP_ALIGN, so on architectures where NET_IP_ALIGN is 2 the IP header now lands misaligned: 64 (NET_SKB_PAD) + 14 (ethernet) + 20 (IP) = 98 Same for the XDP branch: 256 (XDP_PACKET_HEADROOM) + 14 (ethernet) + 20 (IP) = 290 On ARM32 this is fatal, because ldm and ldrd trap on unaligned addresses even when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set. Any received echo request panics the machine, e.g: Unhandled fault: alignment exc...
EPSS
7.5 High
CVSS3