This patch fails at build time:
ERROR: dropbear-2020.81-r0 do_patch: Applying patch
'CVE-2023-48795.patch' on target directory
'/home/steve/builds/poky-contrib-kirkstone/build/tmp/work/core2-64-poky-linux/dropbear/2020.81-r0/dropbear-2020.81'
CmdError('quilt --quiltrc
/home/steve/builds/poky-contrib-kirkstone/build/tmp/work/core2-64-poky-linux/dropbear/2020.81-r0/recipe-sysroot-native/etc/quiltrc
push', 0, 'stdout: Applying patch CVE-2023-48795.patch
patching file cli-session.c
Hunk #2 succeeded at 115 (offset -3 lines).
Hunk #3 succeeded at 475 (offset -14 lines).
patching file common-algo.c
Hunk #1 succeeded at 332 (offset 25 lines).
patching file common-kex.c
Hunk #2 FAILED at 198.
Hunk #3 succeeded at 555 (offset 1 line).
Hunk #4 succeeded at 869 (offset 2 lines).
1 out of 4 hunks FAILED -- rejects in file common-kex.c
patching file kex.h
patching file process-packet.c
Hunk #2 FAILED at 55.
1 out of 3 hunks FAILED -- rejects in file process-packet.c
patching file ssh.h
patching file svr-session.c
Hunk #1 succeeded at 342 (offset -28 lines).
Patch CVE-2023-48795.patch does not apply (enforce with -f)
Please submit a V2 with these issues fixed.
Thanks!
Steve
On Tue, Jan 2, 2024 at 11:02 PM Meenali Gupta via
lists.openembedded.org
<[email protected]> wrote:
>
> From: Meenali Gupta <[email protected]>
>
> A flaw was found in the SSH channel integrity.
> By manipulating sequence numbers during the handshake,
> an attacker can remove the initial messages on the secure
> channel without causing a MAC failure. For example, an attacker
> could disable the ping extension and thus disable the new
> countermeasure in OpenSSH 9.5 against keystroke timing attacks.
>
> Signed-off-by: Meenali Gupta <[email protected]>
> ---
> meta/recipes-core/dropbear/dropbear.inc | 1 +
> .../dropbear/dropbear/CVE-2023-48795.patch | 235 ++++++++++++++++++
> 2 files changed, 236 insertions(+)
> create mode 100644 meta/recipes-core/dropbear/dropbear/CVE-2023-48795.patch
>
> diff --git a/meta/recipes-core/dropbear/dropbear.inc
> b/meta/recipes-core/dropbear/dropbear.inc
> index e61930f7db..a32242949b 100644
> --- a/meta/recipes-core/dropbear/dropbear.inc
> +++ b/meta/recipes-core/dropbear/dropbear.inc
> @@ -30,6 +30,7 @@ SRC_URI =
> "http://matt.ucc.asn.au/dropbear/releases/dropbear-${PV}.tar.bz2 \
> ${@bb.utils.contains('PACKAGECONFIG', 'disable-weak-ciphers',
> 'file://dropbear-disable-weak-ciphers.patch', '', d)} \
> file://CVE-2021-36369.patch \
> file://CVE-2023-36328.patch \
> + file://CVE-2023-48795.patch \
> "
>
> PAM_SRC_URI = "file://0005-dropbear-enable-pam.patch \
> diff --git a/meta/recipes-core/dropbear/dropbear/CVE-2023-48795.patch
> b/meta/recipes-core/dropbear/dropbear/CVE-2023-48795.patch
> new file mode 100644
> index 0000000000..d3f7c014ef
> --- /dev/null
> +++ b/meta/recipes-core/dropbear/dropbear/CVE-2023-48795.patch
> @@ -0,0 +1,235 @@
> +From 768546edcf45794538f81c096f5544a5d35e336f Mon Sep 17 00:00:00 2001
> +From: Matt Johnston <[email protected]>
> +Date: Mon, 20 Nov 2023 14:02:47 +0800
> +Subject: [PATCH] Implement Strict KEX mode
> +
> +As specified by OpenSSH with [email protected] and
> [email protected].
> +
> +CVE: CVE-2023-48795
> +
> +Upstream-Status: Backport
> [https://github.com/mkj/dropbear/commit/6e43be5c7b99dbee49dc72b6f989f29fdd7e9356]
> +
> +Signed-off-by: Meenali Gupta <[email protected]>
> +---
> + cli-session.c | 11 +++++++++++
> + common-algo.c | 6 ++++++
> + common-kex.c | 24 ++++++++++++++++++++++++
> + kex.h | 3 +++
> + process-packet.c | 35 +++++++++++++++++++----------------
> + ssh.h | 4 ++++
> + svr-session.c | 3 +++
> + 7 files changed, 70 insertions(+), 16 deletions(-)
> +
> +diff --git a/cli-session.c b/cli-session.c
> +index 5981b24..d261c8f 100644
> +--- a/cli-session.c
> ++++ b/cli-session.c
> +@@ -46,6 +46,7 @@ static void cli_finished(void) ATTRIB_NORETURN;
> + static void recv_msg_service_accept(void);
> + static void cli_session_cleanup(void);
> + static void recv_msg_global_request_cli(void);
> ++static void cli_algos_initialise(void);
> +
> + struct clientsession cli_ses; /* GLOBAL */
> +
> +@@ -117,6 +118,7 @@ void cli_session(int sock_in, int sock_out, struct
> dropbear_progress_connection
> + }
> +
> + chaninitialise(cli_chantypes);
> ++ cli_algos_initialise();
> +
> + /* Set up cli_ses vars */
> + cli_session_init(proxy_cmd_pid);
> +@@ -487,3 +489,12 @@ void cli_dropbear_log(int priority, const char* format,
> va_list param) {
> + fflush(stderr);
> + }
> +
> ++static void cli_algos_initialise(void) {
> ++ algo_type *algo;
> ++ for (algo = sshkex; algo->name; algo++) {
> ++ if (strcmp(algo->name, SSH_STRICT_KEX_S) == 0) {
> ++ algo->usable = 0;
> ++ }
> ++ }
> ++}
> ++
> +diff --git a/common-algo.c b/common-algo.c
> +index 378f0ca..f9d46eb 100644
> +--- a/common-algo.c
> ++++ b/common-algo.c
> +@@ -307,6 +307,12 @@ algo_type sshkex[] = {
> + /* Set unusable by svr_algos_initialise() */
> + {SSH_EXT_INFO_C, 0, NULL, 1, NULL},
> + #endif
> ++#endif
> ++#if DROPBEAR_CLIENT
> ++ {SSH_STRICT_KEX_C, 0, NULL, 1, NULL},
> ++#endif
> ++#if DROPBEAR_SERVER
> ++ {SSH_STRICT_KEX_S, 0, NULL, 1, NULL},
> + #endif
> + {NULL, 0, NULL, 0, NULL}
> + };
> +diff --git a/common-kex.c b/common-kex.c
> +index ac88442..e6825e1 100644
> +--- a/common-kex.c
> ++++ b/common-kex.c
> +@@ -183,6 +183,10 @@ void send_msg_newkeys() {
> + gen_new_keys();
> + switch_keys();
> +
> ++ if (ses.kexstate.strict_kex) {
> ++ ses.transseq = 0;
> ++ }
> ++
> + TRACE(("leave send_msg_newkeys"))
> + }
> +
> +@@ -194,6 +198,10 @@ void recv_msg_newkeys() {
> + ses.kexstate.recvnewkeys = 1;
> + switch_keys();
> +
> ++ if (ses.kexstate.strict_kex) {
> ++ ses.recvseq = 0;
> ++ }
> ++
> + TRACE(("leave recv_msg_newkeys"))
> + }
> +
> +@@ -550,6 +558,10 @@ void recv_msg_kexinit() {
> +
> + ses.kexstate.recvkexinit = 1;
> +
> ++ if (ses.kexstate.strict_kex && !ses.kexstate.donefirstkex &&
> ses.recvseq != 1) {
> ++ dropbear_exit("First packet wasn't kexinit");
> ++ }
> ++
> + TRACE(("leave recv_msg_kexinit"))
> + }
> +
> +@@ -859,6 +871,18 @@ static void read_kex_algos() {
> + }
> + #endif
> +
> ++ if (!ses.kexstate.donefirstkex) {
> ++ const char* strict_name;
> ++ if (IS_DROPBEAR_CLIENT) {
> ++ strict_name = SSH_STRICT_KEX_S;
> ++ } else {
> ++ strict_name = SSH_STRICT_KEX_C;
> ++ }
> ++ if (buf_has_algo(ses.payload, strict_name) ==
> DROPBEAR_SUCCESS) {
> ++ ses.kexstate.strict_kex = 1;
> ++ }
> ++ }
> ++
> + algo = buf_match_algo(ses.payload, sshkex, kexguess2, &goodguess);
> + allgood &= goodguess;
> + if (algo == NULL || algo->data == NULL) {
> +diff --git a/kex.h b/kex.h
> +index 77cf21a..7fcc3c2 100644
> +--- a/kex.h
> ++++ b/kex.h
> +@@ -83,6 +83,9 @@ struct KEXState {
> +
> + unsigned our_first_follows_matches : 1;
> +
> ++ /* Boolean indicating that strict kex mode is in use */
> ++ unsigned int strict_kex;
> ++
> + time_t lastkextime; /* time of the last kex */
> + unsigned int datatrans; /* data transmitted since last kex */
> + unsigned int datarecv; /* data received since last kex */
> +diff --git a/process-packet.c b/process-packet.c
> +index 9454160..0270f71 100644
> +--- a/process-packet.c
> ++++ b/process-packet.c
> +@@ -44,6 +44,7 @@ void process_packet() {
> +
> + unsigned char type;
> + unsigned int i;
> ++ unsigned int first_strict_kex = ses.kexstate.strict_kex &&
> !ses.kexstate.donefirstkex;
> + time_t now;
> +
> + TRACE2(("enter process_packet"))
> +@@ -54,22 +55,23 @@ void process_packet() {
> + now = monotonic_now();
> + ses.last_packet_time_keepalive_recv = now;
> +
> +- /* These packets we can receive at any time */
> +- switch(type) {
> +-
> +- case SSH_MSG_IGNORE:
> +- goto out;
> +- case SSH_MSG_DEBUG:
> +- goto out;
> ++ if (type == SSH_MSG_DISCONNECT) {
> ++ /* Allowed at any time */
> ++ dropbear_close("Disconnect received");
> ++ }
> +
> +- case SSH_MSG_UNIMPLEMENTED:
> +- /* debugging XXX */
> +- TRACE(("SSH_MSG_UNIMPLEMENTED"))
> +- goto out;
> +-
> +- case SSH_MSG_DISCONNECT:
> +- /* TODO cleanup? */
> +- dropbear_close("Disconnect received");
> ++ /* These packets may be received at any time,
> ++ except during first kex with strict kex */
> ++ if (!first_strict_kex) {
> ++ switch(type) {
> ++ case SSH_MSG_IGNORE:
> ++ goto out;
> ++ case SSH_MSG_DEBUG:
> ++ goto out;
> ++ case SSH_MSG_UNIMPLEMENTED:
> ++ TRACE(("SSH_MSG_UNIMPLEMENTED"))
> ++ goto out;
> ++ }
> + }
> +
> + /* Ignore these packet types so that keepalives don't interfere with
> +@@ -98,7 +100,8 @@ void process_packet() {
> + if (type >= 1 && type <= 49
> + && type != SSH_MSG_SERVICE_REQUEST
> + && type != SSH_MSG_SERVICE_ACCEPT
> +- && type != SSH_MSG_KEXINIT)
> ++ && type != SSH_MSG_KEXINIT
> ++ && !first_strict_kex)
> + {
> + TRACE(("unknown allowed packet during
> kexinit"))
> + recv_unimplemented();
> +diff --git a/ssh.h b/ssh.h
> +index 1b4fec6..ef3efdc 100644
> +--- a/ssh.h
> ++++ b/ssh.h
> +@@ -100,6 +100,10 @@
> + #define SSH_EXT_INFO_C "ext-info-c"
> + #define SSH_SERVER_SIG_ALGS "server-sig-algs"
> +
> ++/* OpenSSH strict KEX feature */
> ++#define SSH_STRICT_KEX_S "[email protected]"
> ++#define SSH_STRICT_KEX_C "[email protected]"
> ++
> + /* service types */
> + #define SSH_SERVICE_USERAUTH "ssh-userauth"
> + #define SSH_SERVICE_USERAUTH_LEN 12
> +diff --git a/svr-session.c b/svr-session.c
> +index 769f073..a538e2c 100644
> +--- a/svr-session.c
> ++++ b/svr-session.c
> +@@ -370,6 +370,9 @@ static void svr_algos_initialise(void) {
> + algo->usable = 0;
> + }
> + #endif
> ++ if (strcmp(algo->name, SSH_STRICT_KEX_C) == 0) {
> ++ algo->usable = 0;
> ++ }
> + }
> + }
> +
> +--
> +2.40.0
> --
> 2.40.0
>
>
>
>
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