51 lines
1.9 KiB
Diff
51 lines
1.9 KiB
Diff
From 586b074026d703c29057b04b1318e984701fe195 Mon Sep 17 00:00:00 2001
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From: Changqing Li <changqing.li@windriver.com>
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Date: Thu, 2 Mar 2023 19:10:47 +0800
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Subject: [PATCH] Properly NULL-terminate GSS receive buffer on error packet
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reception
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pqsecure_open_gss() includes a code path handling error messages with
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v2-style protocol messages coming from the server. The client-side
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buffer holding the error message does not force a NULL-termination, with
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the data of the server getting copied to the errorMessage of the
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connection. Hence, it would be possible for a server to send an
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unterminated string and copy arbitrary bytes in the buffer receiving the
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error message in the client, opening the door to a crash or even data
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exposure.
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As at this stage of the authentication process the exchange has not been
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completed yet, this could be abused by an attacker without Kerberos
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credentials. Clients that have a valid kerberos cache are vulnerable as
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libpq opportunistically requests for it except if gssencmode is
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disabled.
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Author: Jacob Champion
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Backpatch-through: 12
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Security: CVE-2022-41862
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Upstream-Status: Backport [https://github.com/postgres/postgres/commit/71c37797d7bd78266146a5829ab62b3687c47295]
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CVE: CVE-2022-41862
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Signed-off-by: Changqing Li <changqing.li@windriver.com>
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---
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src/interfaces/libpq/fe-secure-gssapi.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/src/interfaces/libpq/fe-secure-gssapi.c b/src/interfaces/libpq/fe-secure-gssapi.c
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index c783a53..a42ebc0 100644
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--- a/src/interfaces/libpq/fe-secure-gssapi.c
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+++ b/src/interfaces/libpq/fe-secure-gssapi.c
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@@ -577,7 +577,8 @@ pqsecure_open_gss(PGconn *conn)
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return result;
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PqGSSRecvLength += ret;
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-
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+ Assert(PqGSSRecvLength < PQ_GSS_RECV_BUFFER_SIZE);
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+ PqGSSRecvBuffer[PqGSSRecvLength] = '\0';
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appendPQExpBuffer(&conn->errorMessage, "%s\n", PqGSSRecvBuffer + 1);
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return PGRES_POLLING_FAILED;
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--
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2.25.1
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