Fixing CVE-2023-48795

pmeunier

Nov 23, 2023, 11:45 AM

VJIXIN4TVZX2ZELE3H5PVZIO6JIG7JZ3UKEJC7TAUYLOPW6GOGOQC

Dependencies

• [2] ZQT6ZVJE Fix broken links in crate metadata
• [3] UHAEQPZU Support ecdsa-sha2-nistp256 keys for authentication
• [4] EUHO3DAZ Send a SSH_MSG_EXT_INFO with server-sig-algs when the client indicates they support extensions by sending ext-info-c. This allows modern clients that don't do ssh-rsa anymore because of sha1 to still use RSA keys with sha2.
• [5] 7FRJYUI6 Reboot because of a bad change
• [6] Y5HHIQXV Wait for the connection to be encrypted in `connect`
• [7] 2WEO7OZL Version updates: getting rid of anyhow + moving to Tokio 1.0
• [8] WXZWQLGL Correct negotiation without OpenSSL
• [9] MFMCIUMJ Fixing authentication with RSA

Change contents

• edit in thrussh/src/sshbuffer.rs at line 27
  [5.166325]

  [5.166325]
  + pub strict: bool,
• edit in thrussh/src/sshbuffer.rs at line 37
  [5.166503]

  [5.166503]
  + strict: false,
• edit in thrussh/src/session.rs at line 70
  [5.174049]

  [5.174049]
  + if self.write_buffer.strict {

  + self.write_buffer.seqn = Wrapping(0);

  + }
• edit in thrussh/src/session.rs at line 419
  [5.185762]

  [5.185762]
  + pub nonstrict_packets_received: bool,
• edit in thrussh/src/session.rs at line 433
  [5.186086]

  [5.186086]
  + nonstrict_packets_received: false,
• edit in thrussh/src/session.rs at line 448
  [5.186564]

  [5.186564]
  + nonstrict_packets_received: false,
• edit in thrussh/src/server/mod.rs at line 619
  [5.223082]

  [5.223082]
  + nonstrict_packets_received: false,
• replacement in thrussh/src/server/mod.rs at line 646
  [5.223854]→[5.223854:223899](∅→∅)
  − Some(Kex::KexInit(kexinit)) => {
  [5.223854]

  [5.223899]
  + Some(Kex::KexInit(mut kexinit)) => {

  + // Two cases: either we already know the algorithm,

  + // meaning that this is a re-keying. Or we don't

  + // meaning this is the initial KEXINIT packet.

  + //

  + // In all other cases, this is an error.
• edit in thrussh/src/server/mod.rs at line 653
  [5.223969]

  [5.223969]
  + let nonstrict_received = kexinit.nonstrict_packets_received;
• replacement in thrussh/src/server/mod.rs at line 660
  [5.224254]→[5.224254:224294](∅→∅)
  − return Ok(session);
  [5.224254]

  [5.224294]
  + if session.common.write_buffer.strict && nonstrict_received {

  + return Err(Error::KexInit.into())

  + }
• replacement in thrussh/src/server/mod.rs at line 664
  [5.224319]→[5.224319:224496](∅→∅)
  − // Else, i.e. if the other side has not started

  − // the key exchange, process its packets by simple

  − // not returning.
  [5.224319]

  [5.224496]
  + kexinit.nonstrict_packets_received = true;
• edit in thrussh/src/server/mod.rs at line 681
  [4.1352]→[5.224889:224925](∅→∅),[5.224889]→[5.224889:224925](∅→∅)
  − return Ok(session);
• edit in thrussh/src/server/mod.rs at line 694
  [5.225404]→[5.225404:225440](∅→∅)
  − return Ok(session);
• edit in thrussh/src/server/mod.rs at line 697
  [5.225529]→[5.225529:225565](∅→∅)
  − return Ok(session);
• edit in thrussh/src/server/kex.rs at line 34
  [5.226766]

  [5.226766]
  + write_buffer.strict = algo.strict_kex;
• edit in thrussh/src/negotiation.rs at line 36
  [4.1423]

  [5.269535]
  + pub strict_kex: bool,
• replacement in thrussh/src/negotiation.rs at line 57
  [3.15373]→[3.15373:15406](∅→∅)
  − kex: &[kex::CURVE25519],
  [3.15373]

  [3.15406]
  + kex: &[kex::CURVE25519, kex::STRICT],
• replacement in thrussh/src/negotiation.rs at line 71
  [3.15809]→[3.15809:15842](∅→∅)
  − kex: &[kex::CURVE25519],
  [3.15809]

  [3.15842]
  + kex: &[kex::CURVE25519, kex::STRICT],
• replacement in thrussh/src/negotiation.rs at line 80
  [5.270122]→[5.270122:270155](∅→∅)
  − kex: &[kex::CURVE25519],
  [5.270122]

  [5.270155]
  + kex: &[kex::CURVE25519, kex::STRICT],
• replacement in thrussh/src/negotiation.rs at line 89
  [5.260]→[5.260:293](∅→∅)
  − kex: &[kex::CURVE25519],
  [5.260]

  [5.293]
  + kex: &[kex::CURVE25519, kex::STRICT],
• replacement in thrussh/src/negotiation.rs at line 97
  [5.270416]→[5.270416:270449](∅→∅)
  − kex: &[kex::CURVE25519],
  [5.270416]

  [3.16168]
  + kex: &[kex::CURVE25519, kex::STRICT],
• edit in thrussh/src/negotiation.rs at line 178
  [4.1623]

  [5.272078]
  + let client_supports_strict = Self::select(&[kex::STRICT], kex_string).is_some();

  + let server_supports_strict = Self::select(&[kex::STRICT], kex_string).is_some();

  +
• edit in thrussh/src/negotiation.rs at line 243
  [4.1706]

  [5.274587]
  + strict_kex: client_supports_strict && server_supports_strict
• edit in thrussh/src/kex.rs at line 48
  [5.308346]

  [4.1791]
  + pub const STRICT: Name = Name("kex-strict-c-v00@openssh.com");
• edit in thrussh/src/client/mod.rs at line 1000
  [5.365830]

  [5.365830]
  + nonstrict_packets_received: false,
• replacement in thrussh/src/client/mod.rs at line 1114
  [5.369605]→[5.369605:369646](∅→∅)
  − Some(Kex::KexInit(kexinit)) => {
  [5.369605]

  [5.369646]
  + Some(Kex::KexInit(mut kexinit)) => {
• edit in thrussh/src/client/mod.rs at line 1119
  [5.369794]

  [5.369794]
  + let nonstrict_received = kexinit.nonstrict_packets_received;
• edit in thrussh/src/client/mod.rs at line 1126
  [5.370070]

  [5.370070]
  + if session.common.write_buffer.strict && nonstrict_received {

  + return Err(Error::KexInit.into())

  + }
• edit in thrussh/src/client/mod.rs at line 1130
  [5.370104]

  [5.370104]
  + } else {

  + kexinit.nonstrict_packets_received = true;

  + session.common.kex = Some(Kex::KexInit(kexinit))
• edit in thrussh/src/client/kex.rs at line 28
  [5.382499]

  [5.382499]
  +

  + write_buffer.strict = algo.strict_kex;
• replacement in README.md at line 23
  [2.601]→[5.442203:442349](∅→∅),[5.442203]→[5.442203:442349](∅→∅)
  − Thrussh has a full disclosure vulnerability policy.

  − Please do NOT attempt to report any security vulnerability in this code privately to anybody.
  [2.601]
  + Thrussh has a responsible disclosure vulnerability policy. Please contact [contact@pijul.org](mailto:contact@pijul.org) if you have identified a security issue.