这篇文章上次修改于 654 天前，可能其部分内容已经发生变化，如有疑问可询问作者。 系统升级到ubuntu 22.04后忽然发现原来工作的证书登录不能用了 经过搜索发现是openssh升级导致默认移除了ssh-rsa sha1的支持 2021年09月26日发布的OpenSSH 8.8中移除了对RSA-SHA1的支持 https://www.openssh.com/txt/release-8.8 <!--more--> ``` Potentially-incompatible changes ================================ This release disables RSA signatures using the SHA-1 hash algorithm by default. This change has been made as the SHA-1 hash algorithm is cryptographically broken, and it is possible to create chosen-prefix hash collisions for <USD$50K [1] For most users, this change should be invisible and there is no need to replace ssh-rsa keys. OpenSSH has supported RFC8332 RSA/SHA-256/512 signatures since release 7.2 and existing ssh-rsa keys will automatically use the stronger algorithm where possible. Incompatibility is more likely when connecting to older SSH implementations that have not been upgraded or have not closely tracked improvements in the SSH protocol. For these cases, it may be necessary to selectively re-enable RSA/SHA1 to allow connection and/or user authentication via the HostkeyAlgorithms and PubkeyAcceptedAlgorithms options. For example, the following stanza in ~/.ssh/config will enable RSA/SHA1 for host and user authentication for a single destination host: Host old-host HostkeyAlgorithms +ssh-rsa PubkeyAcceptedAlgorithms +ssh-rsa We recommend enabling RSA/SHA1 only as a stopgap measure until legacy implementations can be upgraded or reconfigured with another key type (such as ECDSA or Ed25519). [1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust" Leurent, G and Peyrin, T (2020) https://eprint.iacr.org/2020/014.pdf ``` 如果您升级到OpenSSH 8.8或以上版本，则使用ssh推拉Gitee代码时会出现校验不通过的问题 ## 解决办法 下述三种方案任选其一即可 1: 配置OpenSSH服务允许使用RSA-SHA1key 在服务端加配置，启用rsa-sha1 ``` HostkeyAlgorithms +ssh-rsa PubkeyAcceptedAlgorithms +ssh-rsa ``` 2: 换用其他算法生成ssh key (官方推荐) ``` ssh-keygen -t ed25519 -C "your comment" ``` 3: 暂时不要使用OpenSSH 8.8及以上版本 update: openwrt 21.x版本以下不支持ed25519，众多的服务器远程管理卡和硬件设备估计也都不支持ed25519，因此需要更换其他算法，比如 ``` ssh-keygen -b 2048 -t rsa -E sha256 -f filename ```
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