Fix CVE-2018-15473 (#1619064)
This commit is contained in:
Jakub Jelen
parent
1b87361339
commit
8ebd1ac76b
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@ -0,0 +1,146 @@
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From 779974d35b4859c07bc3cb8a12c74b43b0a7d1e0 Mon Sep 17 00:00:00 2001
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From: djm <djm@openbsd.org>
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Date: Tue, 31 Jul 2018 03:10:27 +0000
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Subject: [PATCH] =?UTF-8?q?delay=20bailout=20for=20invalid=20authenticatin?=
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=?UTF-8?q?g=20user=20until=20after=20the=20packet=20containing=20the=20re?=
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=?UTF-8?q?quest=20has=20been=20fully=20parsed.=20Reported=20by=20Dariusz?=
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=?UTF-8?q?=20Tytko=20and=20Micha=C5=82=20Sajdak;=20ok=20deraadt?=
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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---
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usr.bin/ssh/auth2-gss.c | 11 +++++++----
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usr.bin/ssh/auth2-hostbased.c | 11 ++++++-----
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usr.bin/ssh/auth2-pubkey.c | 25 +++++++++++++++----------
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3 files changed, 28 insertions(+), 19 deletions(-)
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diff --git a/usr.bin/ssh/auth2-gss.c b/usr.bin/ssh/auth2-gss.c
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index 649c830916a..c919ef4c353 100644
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--- a/usr.bin/ssh/auth2-gss.c
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+++ b/usr.bin/ssh/auth2-gss.c
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@@ -65,9 +65,6 @@ userauth_gssapi(struct ssh *ssh)
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u_int len;
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u_char *doid = NULL;
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- if (!authctxt->valid || authctxt->user == NULL)
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- return (0);
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-
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mechs = packet_get_int();
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if (mechs == 0) {
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debug("Mechanism negotiation is not supported");
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@@ -101,6 +98,12 @@ userauth_gssapi(struct ssh *ssh)
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return (0);
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}
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+ if (!authctxt->valid || authctxt->user == NULL) {
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+ debug2("%s: disabled because of invalid user", __func__);
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+ free(doid);
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+ return (0);
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+ }
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+
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if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &goid)))) {
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if (ctxt != NULL)
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ssh_gssapi_delete_ctx(&ctxt);
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diff --git a/usr.bin/ssh/auth2-hostbased.c b/usr.bin/ssh/auth2-hostbased.c
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index ad335555934..fb5e5f42272 100644
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--- a/usr.bin/ssh/auth2-hostbased.c
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+++ b/usr.bin/ssh/auth2-hostbased.c
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@@ -66,10 +66,6 @@ userauth_hostbased(struct ssh *ssh)
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size_t alen, blen, slen;
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int r, pktype, authenticated = 0;
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- if (!authctxt->valid) {
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- debug2("%s: disabled because of invalid user", __func__);
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- return 0;
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- }
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/* XXX use sshkey_froms() */
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if ((r = sshpkt_get_cstring(ssh, &pkalg, &alen)) != 0 ||
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(r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 ||
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@@ -116,6 +112,11 @@ userauth_hostbased(struct ssh *ssh)
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goto done;
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}
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+ if (!authctxt->valid || authctxt->user == NULL) {
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+ debug2("%s: disabled because of invalid user", __func__);
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+ goto done;
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+ }
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+
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service = ssh->compat & SSH_BUG_HBSERVICE ? "ssh-userauth" :
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authctxt->service;
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if ((b = sshbuf_new()) == NULL)
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diff --git a/usr.bin/ssh/auth2-pubkey.c b/usr.bin/ssh/auth2-pubkey.c
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index 195da5e2111..af9e5f04c45 100644
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--- a/usr.bin/ssh/auth2-pubkey.c
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+++ b/usr.bin/ssh/auth2-pubkey.c
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@@ -86,18 +86,14 @@ userauth_pubkey(struct ssh *ssh)
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userauth_pubkey(struct ssh *ssh)
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{
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Authctxt *authctxt = ssh->authctxt;
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- struct sshbuf *b;
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+ struct sshbuf *b = NULL;
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struct sshkey *key = NULL;
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- char *pkalg, *userstyle = NULL, *fp = NULL;
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- u_char *pkblob, *sig, have_sig;
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+ char *pkalg = NULL, *userstyle = NULL, *fp = NULL;
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+ u_char *pkblob = NULL, *sig = NULL, have_sig;
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size_t blen, slen;
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int r, pktype;
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int authenticated = 0;
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- if (!authctxt->valid) {
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- debug2("%s: disabled because of invalid user", __func__);
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- return 0;
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- }
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if ((r = sshpkt_get_u8(ssh, &have_sig)) != 0)
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fatal("%s: sshpkt_get_u8 failed: %s", __func__, ssh_err(r));
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if (ssh->compat & SSH_BUG_PKAUTH) {
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@@ -164,6 +160,11 @@ userauth_pubkey(struct ssh *ssh)
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fatal("%s: sshbuf_put_string session id: %s",
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__func__, ssh_err(r));
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}
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+ if (!authctxt->valid || authctxt->user == NULL) {
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+ debug2("%s: disabled because of invalid user",
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+ __func__);
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+ goto done;
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+ }
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/* reconstruct packet */
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xasprintf(&userstyle, "%s%s%s%s%s", authctxt->user,
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authctxt->style ? ":" : "",
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@@ -180,7 +181,6 @@ userauth_pubkey(struct ssh *ssh)
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#ifdef DEBUG_PK
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sshbuf_dump(b, stderr);
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#endif
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-
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/* test for correct signature */
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authenticated = 0;
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if (PRIVSEP(user_key_allowed(authctxt->pw, key, 1)) &&
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@@ -191,7 +191,6 @@ userauth_pubkey(struct ssh *ssh)
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authenticated = 1;
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}
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sshbuf_free(b);
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- free(sig);
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auth2_record_key(authctxt, authenticated, key);
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} else {
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debug("%s: test whether pkalg/pkblob are acceptable for %s %s",
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@@ -202,6 +201,11 @@ userauth_pubkey(struct ssh *ssh)
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if ((r = sshpkt_get_end(ssh)) != 0)
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fatal("%s: %s", __func__, ssh_err(r));
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+ if (!authctxt->valid || authctxt->user == NULL) {
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+ debug2("%s: disabled because of invalid user",
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+ __func__);
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+ goto done;
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+ }
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/* XXX fake reply and always send PK_OK ? */
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/*
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* XXX this allows testing whether a user is allowed
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@@ -235,6 +239,7 @@ userauth_pubkey(struct ssh *ssh)
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free(pkalg);
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free(pkblob);
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free(fp);
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+ free(sig);
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return authenticated;
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}
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@ -233,6 +233,8 @@ Patch949: openssh-7.6p1-cleanup-selinux.patch
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Patch950: openssh-7.5p1-sandbox.patch
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# PermitOpen bug in OpenSSH 7.6:
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Patch951: openssh-7.6p1-permitopen-bug.patch
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# CVE-2018-15473: User "enumeration" via malformed packets in authentication requests
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Patch952: openssh-7.6p1-CVE-2018-15473.patch
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License: BSD
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@ -456,6 +458,7 @@ popd
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%patch949 -p1 -b .refactor
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%patch950 -p1 -b .sandbox
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%patch951 -p1 -b .permitOpen
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%patch952 -p3 -b .enumeration
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%patch200 -p1 -b .audit
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%patch201 -p1 -b .audit-race
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