2c22bd5280
full diff: https://github.com/golang/net/compare/ab34263943818b32f575efc978 This fixes the same CVE as go1.21.3 and go1.20.10; - net/http: rapid stream resets can cause excessive work A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded to the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing. HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit. New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection. This issue is also fixed in golang.org/x/net/http2 v0.17.0, for users manually configuring HTTP/2. The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function. This is CVE-2023-39325 and Go issue https://go.dev/issue/63417. This is also tracked by CVE-2023-44487. Dependency full diffs: a3d24e80b04bd7...v0.17.0 https://github.com/golang/sys/compare/33da011f77ade50ff5b6a6fb4a 9a1e6d6b285809...v0.13.0 https://github.com/golang/text/compare/v0.3.3...v0.13.0 https://github.com/golang/crypto/compare/c1f2f97bffc9c53fc40a1a28a5 b460094c0050d9...v0.14.0 Signed-off-by: Cory Snider <csnider@mirantis.com>
80 lines
3.1 KiB
Go
80 lines
3.1 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Package bpf implements marshaling and unmarshaling of programs for the
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Berkeley Packet Filter virtual machine, and provides a Go implementation
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of the virtual machine.
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BPF's main use is to specify a packet filter for network taps, so that
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the kernel doesn't have to expensively copy every packet it sees to
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userspace. However, it's been repurposed to other areas where running
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user code in-kernel is needed. For example, Linux's seccomp uses BPF
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to apply security policies to system calls. For simplicity, this
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documentation refers only to packets, but other uses of BPF have their
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own data payloads.
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BPF programs run in a restricted virtual machine. It has almost no
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access to kernel functions, and while conditional branches are
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allowed, they can only jump forwards, to guarantee that there are no
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infinite loops.
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# The virtual machine
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The BPF VM is an accumulator machine. Its main register, called
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register A, is an implicit source and destination in all arithmetic
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and logic operations. The machine also has 16 scratch registers for
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temporary storage, and an indirection register (register X) for
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indirect memory access. All registers are 32 bits wide.
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Each run of a BPF program is given one packet, which is placed in the
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VM's read-only "main memory". LoadAbsolute and LoadIndirect
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instructions can fetch up to 32 bits at a time into register A for
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examination.
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The goal of a BPF program is to produce and return a verdict (uint32),
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which tells the kernel what to do with the packet. In the context of
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packet filtering, the returned value is the number of bytes of the
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packet to forward to userspace, or 0 to ignore the packet. Other
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contexts like seccomp define their own return values.
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In order to simplify programs, attempts to read past the end of the
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packet terminate the program execution with a verdict of 0 (ignore
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packet). This means that the vast majority of BPF programs don't need
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to do any explicit bounds checking.
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In addition to the bytes of the packet, some BPF programs have access
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to extensions, which are essentially calls to kernel utility
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functions. Currently, the only extensions supported by this package
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are the Linux packet filter extensions.
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# Examples
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This packet filter selects all ARP packets.
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bpf.Assemble([]bpf.Instruction{
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// Load "EtherType" field from the ethernet header.
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bpf.LoadAbsolute{Off: 12, Size: 2},
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// Skip over the next instruction if EtherType is not ARP.
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bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x0806, SkipTrue: 1},
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// Verdict is "send up to 4k of the packet to userspace."
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bpf.RetConstant{Val: 4096},
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// Verdict is "ignore packet."
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bpf.RetConstant{Val: 0},
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})
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This packet filter captures a random 1% sample of traffic.
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bpf.Assemble([]bpf.Instruction{
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// Get a 32-bit random number from the Linux kernel.
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bpf.LoadExtension{Num: bpf.ExtRand},
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// 1% dice roll?
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bpf.JumpIf{Cond: bpf.JumpLessThan, Val: 2^32/100, SkipFalse: 1},
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// Capture.
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bpf.RetConstant{Val: 4096},
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// Ignore.
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bpf.RetConstant{Val: 0},
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})
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*/
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package bpf // import "golang.org/x/net/bpf"
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