40 lines
1.2 KiB
Diff
40 lines
1.2 KiB
Diff
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Fix a memory exhaustion bug in the key exchange, whereby an unauthenticated user
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could potentially consume 38400 MB of memory on the server:
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http://seclists.org/oss-sec/2016/q4/185
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Patch adapted from upstream source repository:
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https://github.com/openssh/openssh-portable/commit/ec165c392ca54317dbe3064a8c200de6531e89ad
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From ec165c392ca54317dbe3064a8c200de6531e89ad Mon Sep 17 00:00:00 2001
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From: "markus@openbsd.org" <markus@openbsd.org>
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Date: Mon, 10 Oct 2016 19:28:48 +0000
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Subject: [PATCH] upstream commit
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Unregister the KEXINIT handler after message has been
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received. Otherwise an unauthenticated peer can repeat the KEXINIT and cause
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allocation of up to 128MB -- until the connection is closed. Reported by
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shilei-c at 360.cn
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Upstream-ID: 43649ae12a27ef94290db16d1a98294588b75c05
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---
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kex.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/kex.c b/kex.c
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index 3f97f8c..6a94bc5 100644
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--- a/kex.c
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+++ b/kex.c
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@@ -481,6 +481,7 @@ kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
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if (kex == NULL)
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return SSH_ERR_INVALID_ARGUMENT;
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+ ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
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ptr = sshpkt_ptr(ssh, &dlen);
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if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
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return r;
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--
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2.10.1
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