diff options
Diffstat (limited to 'meta-oe/recipes-support/libssh/libssh/CVE-2023-48795-1.patch')
| -rw-r--r-- | meta-oe/recipes-support/libssh/libssh/CVE-2023-48795-1.patch | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/meta-oe/recipes-support/libssh/libssh/CVE-2023-48795-1.patch b/meta-oe/recipes-support/libssh/libssh/CVE-2023-48795-1.patch new file mode 100644 index 0000000000..413e5b3d11 --- /dev/null +++ b/meta-oe/recipes-support/libssh/libssh/CVE-2023-48795-1.patch @@ -0,0 +1,385 @@ +From 4cef5e965a46e9271aed62631b152e4bd23c1e3c Mon Sep 17 00:00:00 2001 +From: Aris Adamantiadis <aris@0xbadc0de.be> +Date: Tue, 12 Dec 2023 23:09:57 +0100 +Subject: [PATCH] CVE-2023-48795: client side mitigation + +Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be> +Signed-off-by: Jakub Jelen <jjelen@redhat.com> +Reviewed-by: Andreas Schneider <asn@cryptomilk.org> + +Upstream-Status: Backport [https://gitlab.com/libssh/libssh-mirror/-/commit/4cef5e965a46e9271aed62631b152e4bd23c1e3c] +CVE: CVE-2023-48795 +Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> +--- + include/libssh/packet.h | 1 + + include/libssh/session.h | 6 +++++ + src/curve25519.c | 18 +++---------- + src/dh.c | 6 +---- + src/ecdh.c | 7 +---- + src/ecdh_crypto.c | 10 ++----- + src/ecdh_gcrypt.c | 10 +++---- + src/ecdh_mbedcrypto.c | 11 +++----- + src/kex.c | 34 ++++++++++++++++++++---- + src/packet.c | 56 +++++++++++++++++++++++++++++++++++++++- + src/packet_cb.c | 12 +++++++++ + 11 files changed, 118 insertions(+), 53 deletions(-) + +diff --git a/include/libssh/packet.h b/include/libssh/packet.h +index fbe09700..8800e16b 100644 +--- a/include/libssh/packet.h ++++ b/include/libssh/packet.h +@@ -63,6 +63,7 @@ SSH_PACKET_CALLBACK(ssh_packet_ext_info); + SSH_PACKET_CALLBACK(ssh_packet_kexdh_init); + #endif + ++int ssh_packet_send_newkeys(ssh_session session); + int ssh_packet_send_unimplemented(ssh_session session, uint32_t seqnum); + int ssh_packet_parse_type(ssh_session session); + //int packet_flush(ssh_session session, int enforce_blocking); +diff --git a/include/libssh/session.h b/include/libssh/session.h +index 23633cc2..b8810f54 100644 +--- a/include/libssh/session.h ++++ b/include/libssh/session.h +@@ -69,6 +69,12 @@ enum ssh_pending_call_e { + /* Client successfully authenticated */ + #define SSH_SESSION_FLAG_AUTHENTICATED 2 + ++/* The current SSH2 session implements the "strict KEX" feature and should behave ++ * differently on SSH2_MSG_NEWKEYS. */ ++#define SSH_SESSION_FLAG_KEX_STRICT 0x0010 ++/* Unexpected packets have been sent while the session was still unencrypted */ ++#define SSH_SESSION_FLAG_KEX_TAINTED 0x0020 ++ + /* codes to use with ssh_handle_packets*() */ + /* Infinite timeout */ + #define SSH_TIMEOUT_INFINITE -1 +diff --git a/src/curve25519.c b/src/curve25519.c +index 167209f4..6eda5feb 100644 +--- a/src/curve25519.c ++++ b/src/curve25519.c +@@ -166,12 +166,7 @@ int ssh_client_curve25519_reply(ssh_session session, ssh_buffer packet){ + } + + /* Send the MSG_NEWKEYS */ +- if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) { +- goto error; +- } +- +- rc=ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); ++ rc = ssh_packet_send_newkeys(session); + return rc; + error: + return SSH_ERROR; +@@ -297,15 +292,10 @@ int ssh_server_curve25519_init(ssh_session session, ssh_buffer packet){ + return SSH_ERROR; + } + +- /* Send the MSG_NEWKEYS */ +- rc = ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS); +- if (rc < 0) { +- goto error; +- } +- + session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; +- rc = ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); ++ ++ /* Send the MSG_NEWKEYS */ ++ rc = ssh_packet_send_newkeys(session); + + return rc; + error: +diff --git a/src/dh.c b/src/dh.c +index cc12fd46..33883f2d 100644 +--- a/src/dh.c ++++ b/src/dh.c +@@ -735,11 +735,7 @@ int ssh_client_dh_reply(ssh_session session, ssh_buffer packet){ + } + + /* Send the MSG_NEWKEYS */ +- if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) { +- goto error; +- } +- +- rc=ssh_packet_send(session); ++ rc = ssh_packet_send_newkeys(session); + SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); + return rc; + error: +diff --git a/src/ecdh.c b/src/ecdh.c +index f7fcaf13..1fef7ec9 100644 +--- a/src/ecdh.c ++++ b/src/ecdh.c +@@ -72,12 +72,7 @@ int ssh_client_ecdh_reply(ssh_session session, ssh_buffer packet){ + } + + /* Send the MSG_NEWKEYS */ +- if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) { +- goto error; +- } +- +- rc=ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); ++ rc = ssh_packet_send_newkeys(session); + return rc; + error: + return SSH_ERROR; +diff --git a/src/ecdh_crypto.c b/src/ecdh_crypto.c +index 24f21c03..7e5f0cc7 100644 +--- a/src/ecdh_crypto.c ++++ b/src/ecdh_crypto.c +@@ -318,15 +318,9 @@ int ssh_server_ecdh_init(ssh_session session, ssh_buffer packet){ + return SSH_ERROR; + } + +- /* Send the MSG_NEWKEYS */ +- rc = ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS); +- if (rc < 0) { +- return SSH_ERROR;; +- } +- + session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; +- rc = ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); ++ /* Send the MSG_NEWKEYS */ ++ rc = ssh_packet_send_newkeys(session); + + return rc; + } +diff --git a/src/ecdh_gcrypt.c b/src/ecdh_gcrypt.c +index e43cacea..c1db7f5d 100644 +--- a/src/ecdh_gcrypt.c ++++ b/src/ecdh_gcrypt.c +@@ -362,17 +362,13 @@ int ssh_server_ecdh_init(ssh_session session, ssh_buffer packet) { + goto out; + } + +- ++ session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; + /* Send the MSG_NEWKEYS */ +- rc = ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS); +- if (rc != SSH_OK) { ++ rc = ssh_packet_send_newkeys(session); ++ if (rc == SSH_ERROR) { + goto out; + } + +- session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; +- rc = ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); +- + out: + gcry_sexp_release(param); + gcry_sexp_release(key); +diff --git a/src/ecdh_mbedcrypto.c b/src/ecdh_mbedcrypto.c +index fa350028..24924508 100644 +--- a/src/ecdh_mbedcrypto.c ++++ b/src/ecdh_mbedcrypto.c +@@ -293,16 +293,13 @@ int ssh_server_ecdh_init(ssh_session session, ssh_buffer packet) + goto out; + } + +- rc = ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS); +- if (rc < 0) { +- rc = SSH_ERROR; ++ session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; ++ /* Send the MSG_NEWKEYS */ ++ rc = ssh_packet_send_newkeys(session); ++ if (rc == SSH_ERROR) { + goto out; + } + +- session->dh_handshake_state = DH_STATE_NEWKEYS_SENT; +- rc = ssh_packet_send(session); +- SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent"); +- + out: + mbedtls_ecp_group_free(&grp); + return rc; +diff --git a/src/kex.c b/src/kex.c +index 82686e4b..7f1bb324 100644 +--- a/src/kex.c ++++ b/src/kex.c +@@ -105,6 +105,9 @@ + + /* RFC 8308 */ + #define KEX_EXTENSION_CLIENT "ext-info-c" ++/* Strict kex mitigation against CVE-2023-48795 */ ++#define KEX_STRICT_CLIENT "kex-strict-c-v00@openssh.com" ++#define KEX_STRICT_SERVER "kex-strict-s-v00@openssh.com" + + /* NOTE: This is a fixed API and the index is defined by ssh_kex_types_e */ + static const char *default_methods[] = { +@@ -521,6 +524,27 @@ SSH_PACKET_CALLBACK(ssh_packet_kexinit){ + goto error; + } + ++ /* ++ * handle the "strict KEX" feature. If supported by peer, then set up the ++ * flag and verify packet sequence numbers. ++ */ ++ if (server_kex) { ++ ok = ssh_match_group(session->next_crypto->client_kex.methods[SSH_KEX], ++ KEX_STRICT_CLIENT); ++ if (ok) { ++ SSH_LOG(SSH_LOG_DEBUG, "Client supports strict kex, enabling."); ++ session->flags |= SSH_SESSION_FLAG_KEX_STRICT; ++ } ++ } else { ++ /* client kex */ ++ ok = ssh_match_group(session->next_crypto->server_kex.methods[SSH_KEX], ++ KEX_STRICT_SERVER); ++ if (ok) { ++ SSH_LOG(SSH_LOG_DEBUG, "Server supports strict kex, enabling."); ++ session->flags |= SSH_SESSION_FLAG_KEX_STRICT; ++ } ++ } ++ + /* + * If client sent a ext-info-c message in the kex list, it supports + * RFC 8308 extension negotiation. +@@ -778,21 +802,21 @@ int ssh_set_client_kex(ssh_session session) + return SSH_OK; + } + +- /* Here we append ext-info-c to the list of kex algorithms */ ++ /* Here we append ext-info-c and kex-strict-c-v00@openssh.com to the list of kex algorithms */ + kex = client->methods[SSH_KEX]; + len = strlen(kex); +- if (len + strlen(KEX_EXTENSION_CLIENT) + 2 < len) { ++ /* Comma, comma, nul byte */ ++ kex_len = len + 1 + strlen(KEX_EXTENSION_CLIENT) + 1 + strlen(KEX_STRICT_CLIENT ) + 1; ++ if (kex_len >= MAX_PACKET_LEN) { + /* Overflow */ + return SSH_ERROR; + } +- kex_len = len + strlen(KEX_EXTENSION_CLIENT) + 2; /* comma, NULL */ + kex_tmp = realloc(kex, kex_len); + if (kex_tmp == NULL) { +- free(kex); + ssh_set_error_oom(session); + return SSH_ERROR; + } +- snprintf(kex_tmp + len, kex_len - len, ",%s", KEX_EXTENSION_CLIENT); ++ snprintf(kex_tmp + len, kex_len - len, ",%s,%s", KEX_EXTENSION_CLIENT, KEX_STRICT_CLIENT); + client->methods[SSH_KEX] = kex_tmp; + + return SSH_OK; +diff --git a/src/packet.c b/src/packet.c +index 61a44237..8025a7ff 100644 +--- a/src/packet.c ++++ b/src/packet.c +@@ -1126,6 +1126,19 @@ int ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user) + } + #endif /* WITH_ZLIB */ + payloadsize = ssh_buffer_get_len(session->in_buffer); ++ if (session->recv_seq == UINT32_MAX) { ++ /* Overflowing sequence numbers is always fishy */ ++ if (session->current_crypto == NULL) { ++ /* don't allow sequence number overflow when unencrypted */ ++ ssh_set_error(session, ++ SSH_FATAL, ++ "Incoming sequence number overflow"); ++ goto error; ++ } else { ++ SSH_LOG(SSH_LOG_WARNING, ++ "Incoming sequence number overflow"); ++ } ++ } + session->recv_seq++; + if (session->raw_counter != NULL) { + session->raw_counter->in_bytes += payloadsize; +@@ -1141,7 +1154,19 @@ int ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user) + SSH_LOG(SSH_LOG_PACKET, + "packet: read type %hhd [len=%d,padding=%hhd,comp=%d,payload=%d]", + session->in_packet.type, packet_len, padding, compsize, payloadsize); +- ++ if (session->current_crypto == NULL) { ++ /* In strict kex, only a few packets are allowed. Taint the session ++ * if we received packets that are normally allowed but to be ++ * refused if we are in strict kex when KEX is over. ++ */ ++ uint8_t type = session->in_packet.type; ++ ++ if (type != SSH2_MSG_KEXINIT && type != SSH2_MSG_NEWKEYS && ++ (type < SSH2_MSG_KEXDH_INIT || ++ type > SSH2_MSG_KEX_DH_GEX_REQUEST)) { ++ session->flags |= SSH_SESSION_FLAG_KEX_TAINTED; ++ } ++ } + /* Check if the packet is expected */ + filter_result = ssh_packet_incoming_filter(session); + +@@ -1153,6 +1178,9 @@ int ssh_packet_socket_callback(const void *data, size_t receivedlen, void *user) + case SSH_PACKET_DENIED: + goto error; + case SSH_PACKET_UNKNOWN: ++ if (session->current_crypto == NULL) { ++ session->flags |= SSH_SESSION_FLAG_KEX_TAINTED; ++ } + ssh_packet_send_unimplemented(session, session->recv_seq - 1); + break; + } +@@ -1276,9 +1304,35 @@ void ssh_packet_process(ssh_session session, uint8_t type){ + if(r==SSH_PACKET_NOT_USED){ + SSH_LOG(SSH_LOG_RARE,"Couldn't do anything with packet type %d",type); + ssh_packet_send_unimplemented(session, session->recv_seq-1); ++ if (session->current_crypto == NULL) { ++ session->flags |= SSH_SESSION_FLAG_KEX_TAINTED; ++ } + } + } + ++/** @internal ++ * @brief sends a SSH_MSG_NEWKEYS when enabling the new negotiated ciphers ++ * @param session the SSH session ++ * @return SSH_ERROR on error, else SSH_OK ++ */ ++int ssh_packet_send_newkeys(ssh_session session) ++{ ++ int rc; ++ ++ /* Send the MSG_NEWKEYS */ ++ rc = ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS); ++ if (rc < 0) { ++ return rc; ++ } ++ ++ rc = ssh_packet_send(session); ++ if (rc == SSH_ERROR) { ++ return rc; ++ } ++ SSH_LOG(SSH_LOG_DEBUG, "SSH_MSG_NEWKEYS sent"); ++ return rc; ++} ++ + /** @internal + * @brief sends a SSH_MSG_UNIMPLEMENTED answer to an unhandled packet + * @param session the SSH session +diff --git a/src/packet_cb.c b/src/packet_cb.c +index 6aa64766..de03fb07 100644 +--- a/src/packet_cb.c ++++ b/src/packet_cb.c +@@ -154,6 +154,18 @@ SSH_PACKET_CALLBACK(ssh_packet_newkeys){ + goto error; + } + ++ if (session->flags & SSH_SESSION_FLAG_KEX_STRICT) { ++ /* reset packet sequence number when running in strict kex mode */ ++ session->recv_seq = 0; ++ /* Check that we aren't tainted */ ++ if (session->flags & SSH_SESSION_FLAG_KEX_TAINTED) { ++ ssh_set_error(session, ++ SSH_FATAL, ++ "Received unexpected packets in strict KEX mode."); ++ goto error; ++ } ++} ++ + if(session->server){ + /* server things are done in server.c */ + session->dh_handshake_state=DH_STATE_FINISHED; +-- +2.25.1 + |