In the Linux kernel, the following vulnerability has been resolved: netfilter: handle unreadable frags sashiko reports: When an skb with unreadable fragments (such as from devmem TCP, where skb_frags_readable(skb) returns false) is processed by the u32 module, skb_copy_bits() will safely return a negative error code [..] xt_u32: bail out with hotdrop in this case. gather_frags: return -1, just as if we had no fragment header. nfnetlink_queue: restrict to the linear part. nfnetlink_log: restrict to the linear part. v2: - skb_zerocopy helpers don't copy readable flag, i.e. nfnetlink_queue is broken too xt_u32 shouldn't return true if hotdrop was set.
https://git.kernel.org/stable/c/fc5bfe63bacf8a3ae307b62b34206406ca733354
https://git.kernel.org/stable/c/da5b58478a9c1b85608c9e40a3b8432d071b409e
https://git.kernel.org/stable/c/57056be3ec12e7d9ecd20a60d4060f510e4f284c
https://git.kernel.org/stable/c/3b13e7635795394705920cca1e1db7e4ca2e334b