From 1d479fc61feacc64adea64da9601f3dfcf6f74b3 Mon Sep 17 00:00:00 2001
From: Chrostoper Ertl <chertl@microsoft.com>
Date: Thu, 28 Nov 2019 16:56:38 +0000
Subject: [PATCH] channel: Fix buffer overflow
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Partial fix for CVE-2020-5208, see
https://github.com/ipmitool/ipmitool/security/advisories/GHSA-g659-9qxw-p7cp

The `ipmi_get_channel_cipher_suites` function does not properly check
the final response’s `data_len`, which can lead to stack buffer overflow
on the final copy.

[Retrieve from:
https://github.com/ipmitool/ipmitool/commit/9452be87181a6e83cfcc768b3ed8321763db50e4

The patch is slightly modified manually. The define
(MAX_CIPHER_SUITE_DATA_LEN) was introduced upstream in another patch.
Replace the define by the value 0x10.]

Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
---
 lib/ipmi_channel.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/ipmi_channel.c b/lib/ipmi_channel.c
index fab2e54..59ac227 100644
--- a/lib/ipmi_channel.c
+++ b/lib/ipmi_channel.c
@@ -413,7 +413,10 @@ ipmi_get_channel_cipher_suites(struct ipmi_intf *intf, const char *payload_type,
 			lprintf(LOG_ERR, "Unable to Get Channel Cipher Suites");
 			return -1;
 		}
-		if (rsp->ccode > 0) {
+		if (rsp->ccode
+		    || rsp->data_len < 1
+		    || rsp->data_len > sizeof(uint8_t) + 0x10)
+		{
 			lprintf(LOG_ERR, "Get Channel Cipher Suites failed: %s",
 					val2str(rsp->ccode, completion_code_vals));
 			return -1;
-- 
2.20.1