revert compat.[ch] section of the following change. It causes

double-free under some circumstances.

--

date: 2018/07/31 03:07:24;  author: djm;  state: Exp;  lines: +33 -18;  commitid: f7g4UI8eeOXReTPh;
fix some memory leaks spotted by Coverity via Jakub Jelen in bz#2366
feedback and ok dtucker@

diff --git a/usr.bin/ssh/compat.c b/usr.bin/ssh/compat.c
index 71a7317..c2bde13 100644 (file)
--- a/usr.bin/ssh/compat.c
+++ b/usr.bin/ssh/compat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.c,v 1.112 2018/07/31 03:07:24 djm Exp $ */
+/* $OpenBSD: compat.c,v 1.113 2018/08/13 02:41:05 djm Exp $ */
 /*
  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  *
@@ -182,17 +182,13 @@ proto_spec(const char *spec)
 }
 
 char *
-compat_cipher_proposal(char *cipher_prop, u_int compat)
+compat_cipher_proposal(char *cipher_prop)
 {
-       char *cp;
-
-       if (!(compat & SSH_BUG_BIGENDIANAES))
+       if (!(datafellows & SSH_BUG_BIGENDIANAES))
                return cipher_prop;
        debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
-       if ((cp = match_filter_blacklist(cipher_prop, "aes*")) == NULL)
+       if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL)
                fatal("match_filter_blacklist failed");
-       free(cipher_prop);
-       cipher_prop = cp;
        debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
        if (*cipher_prop == '\0')
                fatal("No supported ciphers found");
@@ -200,17 +196,13 @@ compat_cipher_proposal(char *cipher_prop, u_int compat)
 }
 
 char *
-compat_pkalg_proposal(char *pkalg_prop, u_int compat)
+compat_pkalg_proposal(char *pkalg_prop)
 {
-       char *cp;
-
-       if (!(compat & SSH_BUG_RSASIGMD5))
+       if (!(datafellows & SSH_BUG_RSASIGMD5))
                return pkalg_prop;
        debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
-       if ((cp = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL)
+       if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL)
                fatal("match_filter_blacklist failed");
-       free(pkalg_prop);
-       pkalg_prop = cp;
        debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
        if (*pkalg_prop == '\0')
                fatal("No supported PK algorithms found");
@@ -218,31 +210,24 @@ compat_pkalg_proposal(char *pkalg_prop, u_int compat)
 }
 
 char *
-compat_kex_proposal(char *kex_prop, u_int compat)
+compat_kex_proposal(char *p)
 {
-       char *cp;
-
-       if ((compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
-               return kex_prop;
-       debug2("%s: original KEX proposal: %s", __func__, kex_prop);
-       if ((compat & SSH_BUG_CURVE25519PAD) != 0) {
-               if ((cp = match_filter_blacklist(kex_prop,
+       if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
+               return p;
+       debug2("%s: original KEX proposal: %s", __func__, p);
+       if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
+               if ((p = match_filter_blacklist(p,
                    "curve25519-sha256@libssh.org")) == NULL)
                        fatal("match_filter_blacklist failed");
-               free(kex_prop);
-               kex_prop = cp;
-       }
-       if ((compat & SSH_OLD_DHGEX) != 0) {
-               if ((cp = match_filter_blacklist(kex_prop,
+       if ((datafellows & SSH_OLD_DHGEX) != 0) {
+               if ((p = match_filter_blacklist(p,
                    "diffie-hellman-group-exchange-sha256,"
                    "diffie-hellman-group-exchange-sha1")) == NULL)
                        fatal("match_filter_blacklist failed");
-               free(kex_prop);
-               kex_prop = cp;
        }
-       debug2("%s: compat KEX proposal: %s", __func__, kex_prop);
-       if (*kex_prop == '\0')
+       debug2("%s: compat KEX proposal: %s", __func__, p);
+       if (*p == '\0')
                fatal("No supported key exchange algorithms found");
-       return kex_prop;
+       return p;
 }
 

diff --git a/usr.bin/ssh/compat.h b/usr.bin/ssh/compat.h
index e287773..d611d33 100644 (file)
--- a/usr.bin/ssh/compat.h
+++ b/usr.bin/ssh/compat.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.h,v 1.53 2018/07/31 03:07:24 djm Exp $ */
+/* $OpenBSD: compat.h,v 1.54 2018/08/13 02:41:05 djm Exp $ */
 
 /*
  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
@@ -65,15 +65,9 @@
 
 u_int    compat_datafellows(const char *);
 int     proto_spec(const char *);
-
-/*
- * compat_*_proposal will update their respective proposals based on the
- * active compat flags. The replacement is performed in-place - i.e. they
- * will free their argument and return a new heap-allocated string.
- */
-char   *compat_cipher_proposal(char *, u_int compat);
-char   *compat_pkalg_proposal(char *, u_int compat);
-char   *compat_kex_proposal(char *, u_int compat);
+char   *compat_cipher_proposal(char *);
+char   *compat_pkalg_proposal(char *);
+char   *compat_kex_proposal(char *);
 
 extern int datafellows;
 #endif

diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c
index c309ab7..957a04b 100644 (file)
--- a/usr.bin/ssh/sshconnect2.c
+++ b/usr.bin/ssh/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.283 2018/07/31 03:07:24 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.284 2018/08/13 02:41:05 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -161,11 +161,11 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 
        if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
                fatal("%s: kex_names_cat", __func__);
-       myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s, datafellows);
+       myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s);
        myproposal[PROPOSAL_ENC_ALGS_CTOS] =
-           compat_cipher_proposal(options.ciphers, datafellows);
+           compat_cipher_proposal(options.ciphers);
        myproposal[PROPOSAL_ENC_ALGS_STOC] =
-           compat_cipher_proposal(options.ciphers, datafellows);
+           compat_cipher_proposal(options.ciphers);
        myproposal[PROPOSAL_COMP_ALGS_CTOS] =
            myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ?
            "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib";
@@ -178,15 +178,14 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
                        fatal("%s: kex_assemble_namelist", __func__);
                free(all_key);
                myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
-                   compat_pkalg_proposal(options.hostkeyalgorithms,
-                   datafellows);
+                   compat_pkalg_proposal(options.hostkeyalgorithms);
        } else {
                /* Enforce default */
                options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG);
                /* Prefer algorithms that we already have keys for */
                myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
                    compat_pkalg_proposal(
-                   order_hostkeyalgs(host, hostaddr, port), datafellows);
+                   order_hostkeyalgs(host, hostaddr, port));
        }
 
        if (options.rekey_limit || options.rekey_interval)
@@ -216,7 +215,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
 
        /* remove ext-info from the KEX proposals for rekeying */
        myproposal[PROPOSAL_KEX_ALGS] =
-           compat_kex_proposal(options.kex_algorithms, datafellows);
+           compat_kex_proposal(options.kex_algorithms);
        if ((r = kex_prop2buf(kex->my, myproposal)) != 0)
                fatal("kex_prop2buf: %s", ssh_err(r));
 

diff --git a/usr.bin/ssh/sshd.c b/usr.bin/ssh/sshd.c
index a125f4a..46b5689 100644 (file)
--- a/usr.bin/ssh/sshd.c
+++ b/usr.bin/ssh/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.513 2018/07/31 03:07:24 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.514 2018/08/13 02:41:05 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -2082,11 +2082,11 @@ do_ssh2_kex(void)
        int r;
 
        myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
-           options.kex_algorithms, datafellows);
+           options.kex_algorithms);
        myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
-           options.ciphers, datafellows);
+           options.ciphers);
        myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
-           options.ciphers, datafellows);
+           options.ciphers);
        myproposal[PROPOSAL_MAC_ALGS_CTOS] =
            myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
 
@@ -2100,7 +2100,7 @@ do_ssh2_kex(void)
                    options.rekey_interval);
 
        myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
-           list_hostkey_types(), datafellows);
+           list_hostkey_types());
 
        /* start key exchange */
        if ((r = kex_setup(active_state, myproposal)) != 0)