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ddce1e0917
A listening socket linked to a sockmap has its sk_prot overridden. It points to one of the struct proto variants in tcp_bpf_prots. The variant depends on the socket's family and which sockmap programs are attached. A child socket cloned from a TCP listener initially inherits their sk_prot. But before cloning is finished, we restore the child's proto to the listener's original non-tcp_bpf_prots one. This happens in tcp_create_openreq_child -> tcp_bpf_clone. Today, in tcp_bpf_clone we detect if the child's proto should be restored by checking only for the TCP_BPF_BASE proto variant. This is not correct. The sk_prot of listening socket linked to a sockmap can point to to any variant in tcp_bpf_prots. If the listeners sk_prot happens to be not the TCP_BPF_BASE variant, then the child socket unintentionally is left if the inherited sk_prot by tcp_bpf_clone. This leads to issues like infinite recursion on close [1], because the child state is otherwise not set up for use with tcp_bpf_prot operations. Adjust the check in tcp_bpf_clone to detect all of tcp_bpf_prots variants. Note that it wouldn't be sufficient to check the socket state when overriding the sk_prot in tcp_bpf_update_proto in order to always use the TCP_BPF_BASE variant for listening sockets. Since commitb8b8315e39("bpf, sockmap: Remove unhash handler for BPF sockmap usage") it is possible for a socket to transition to TCP_LISTEN state while already linked to a sockmap, e.g. connect() -> insert into map -> connect(AF_UNSPEC) -> listen(). [1]: https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/ Fixes:e80251555f("tcp_bpf: Don't let child socket inherit parent protocol ops on copy") Reported-by: syzbot+04c21ed96d861dccc5cd@syzkaller.appspotmail.com Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-2-1e0ee7ac2f90@cloudflare.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_HELPER_MACROS_H_
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#define _LINUX_HELPER_MACROS_H_
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#define __find_closest(x, a, as, op) \
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({ \
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typeof(as) __fc_i, __fc_as = (as) - 1; \
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typeof(x) __fc_x = (x); \
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typeof(*a) const *__fc_a = (a); \
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for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) { \
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if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] + \
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__fc_a[__fc_i + 1], 2)) \
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break; \
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} \
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(__fc_i); \
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})
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/**
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* find_closest - locate the closest element in a sorted array
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* @x: The reference value.
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* @a: The array in which to look for the closest element. Must be sorted
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* in ascending order.
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* @as: Size of 'a'.
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*
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* Returns the index of the element closest to 'x'.
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*/
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#define find_closest(x, a, as) __find_closest(x, a, as, <=)
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/**
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* find_closest_descending - locate the closest element in a sorted array
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* @x: The reference value.
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* @a: The array in which to look for the closest element. Must be sorted
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* in descending order.
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* @as: Size of 'a'.
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*
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* Similar to find_closest() but 'a' is expected to be sorted in descending
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* order.
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*/
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#define find_closest_descending(x, a, as) __find_closest(x, a, as, >=)
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/**
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* is_insidevar - check if the @ptr points inside the @var memory range.
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* @ptr: the pointer to a memory address.
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* @var: the variable which address and size identify the memory range.
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*
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* Evaluates to true if the address in @ptr lies within the memory
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* range allocated to @var.
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*/
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#define is_insidevar(ptr, var) \
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((uintptr_t)(ptr) >= (uintptr_t)(var) && \
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(uintptr_t)(ptr) < (uintptr_t)(var) + sizeof(var))
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#endif
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