CVE-2024-56719

In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: fix TSO DMA API usage causing oops

Commit 66600fac7a98 ("net: stmmac: TSO: Fix unbalanced DMA map/unmap for non-paged SKB data") moved the assignment of tx_skbuff_dma[]'s members to be later in stmmac_tso_xmit().

The buf (dma cookie) and len stored in this structure are passed to dma_unmap_single() by stmmac_tx_clean(). The DMA API requires that the dma cookie passed to dma_unmap_single() is the same as the value returned from dma_map_single(). However, by moving the assignment later, this is not the case when priv->dma_cap.addr64 > 32 as "des" is offset by proto_hdr_len.

This causes problems such as:

dwc-eth-dwmac 2490000.ethernet eth0: Tx DMA map failed

and with DMA_API_DEBUG enabled:

DMA-API: dwc-eth-dwmac 2490000.ethernet: device driver tries to +free DMA memory it has not allocated [device address=0x000000ffffcf65c0] [size=66 bytes]

Fix this by maintaining "des" as the original DMA cookie, and use tso_des to pass the offset DMA cookie to stmmac_tso_allocator().

Full details of the crashes can be found at: https://lore.kernel.org/all/[email protected]/ https://lore.kernel.org/all/klkzp5yn5kq5efgtrow6wbvnc46bcqfxs65nz3qy77ujr5turc@bwwhelz2l4dw/

This vulnerability is rated Moderate rather than Important because exploitation requires local access on systems equipped with specific Synopsys DesignWare Ethernet hardware, resulting in a denial of service (kernel crash) without compromising data confidentiality or integrity. The flaw specifically affects network adapters driven by the stmmac driver when handling TCP Segmentation Offload packets with 64-bit direct memory access enabled. Because this network interface controller is predominantly deployed in specialized embedded or system-on-chip environments rather than standard enterprise servers, typical Red Hat Enterprise Linux installations are not exposed under default configurations.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.