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From 0e4e9825e637a15707a910539d71fe65e7e12d7b Mon Sep 17 00:00:00 2001
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From: Kamil Dudka <kdudka@redhat.com>
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Date: Tue, 19 Mar 2019 13:45:22 +0100
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Subject: [PATCH] Resolves: CVE-2019-3862 - fix out-of-bounds memory comparison
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... with specially crafted message channel request
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Upstream-Patch: https://libssh2.org/1.8.0-CVE/CVE-2019-3862.patch
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---
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src/packet.c | 14 ++++++++------
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1 file changed, 8 insertions(+), 6 deletions(-)
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diff --git a/src/packet.c b/src/packet.c
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index aa10633..c950b5d 100644
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--- a/src/packet.c
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+++ b/src/packet.c
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@@ -775,8 +775,8 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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uint32_t len = _libssh2_ntohu32(data + 5);
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unsigned char want_reply = 1;
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- if(len < (datalen - 10))
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- want_reply = data[9 + len];
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+ if((len + 9) < datalen)
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+ want_reply = data[len + 9];
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_libssh2_debug(session,
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LIBSSH2_TRACE_CONN,
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@@ -784,6 +784,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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channel, len, data + 9, want_reply);
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if (len == sizeof("exit-status") - 1
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+ && (sizeof("exit-status") - 1 + 9) <= datalen
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&& !memcmp("exit-status", data + 9,
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sizeof("exit-status") - 1)) {
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@@ -792,7 +793,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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channelp =
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_libssh2_channel_locate(session, channel);
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- if (channelp) {
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+ if (channelp && (sizeof("exit-status") + 13) <= datalen) {
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channelp->exit_status =
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_libssh2_ntohu32(data + 9 + sizeof("exit-status"));
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_libssh2_debug(session, LIBSSH2_TRACE_CONN,
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@@ -805,13 +806,14 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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}
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else if (len == sizeof("exit-signal") - 1
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+ && (sizeof("exit-signal") - 1 + 9) <= datalen
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&& !memcmp("exit-signal", data + 9,
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sizeof("exit-signal") - 1)) {
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/* command terminated due to signal */
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if(datalen >= 20)
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channelp = _libssh2_channel_locate(session, channel);
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- if (channelp) {
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+ if (channelp && (sizeof("exit-signal") + 13) <= datalen) {
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/* set signal name (without SIG prefix) */
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uint32_t namelen =
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_libssh2_ntohu32(data + 9 + sizeof("exit-signal"));
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@@ -827,9 +829,9 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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if (!channelp->exit_signal)
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rc = _libssh2_error(session, LIBSSH2_ERROR_ALLOC,
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"memory for signal name");
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- else {
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+ else if ((sizeof("exit-signal") + 13 + namelen <= datalen)) {
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memcpy(channelp->exit_signal,
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- data + 13 + sizeof("exit_signal"), namelen);
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+ data + 13 + sizeof("exit-signal"), namelen);
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channelp->exit_signal[namelen] = '\0';
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/* TODO: save error message and language tag */
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_libssh2_debug(session, LIBSSH2_TRACE_CONN,
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--
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2.17.2
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