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From 40f6c913f63cdbfa81daa7ac7f1c7415bb99edeb Mon Sep 17 00:00:00 2001
From: Daniel Gustafsson <daniel@yesql.se>
Date: Sat, 19 Jan 2019 00:42:47 +0100
Subject: [PATCH 3/3] smtp: avoid risk of buffer overflow in strtol
If the incoming len 5, but the buffer does not have a termination
after 5 bytes, the strtol() call may keep reading through the line
buffer until is exceeds its boundary. Fix by ensuring that we are
using a bounded read with a temporary buffer on the stack.
Bug: https://curl.haxx.se/docs/CVE-2019-3823.html
Reported-by: Brian Carpenter (Geeknik Labs)
CVE-2019-3823
Upstream-Status: Backport
[https://github.com/curl/curl/commit
/39df4073e5413fcdbb5a38da0c1ce6f1c0ceb484]
CVE: CVE-2019-3823
Signed-off-by: Kevin Weng <t-keweng@microsoft.com>
---
lib/smtp.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/lib/smtp.c b/lib/smtp.c
index ecf10a41a..1b9f92d30 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -5,7 +5,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
- * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
@@ -207,8 +207,12 @@ static bool smtp_endofresp(struct connectdata *conn, char *line, size_t len,
Section 4. Examples of RFC-4954 but some e-mail servers ignore this and
only send the response code instead as per Section 4.2. */
if(line[3] == ' ' || len == 5) {
+ char tmpline[6];
+
result = TRUE;
- *resp = curlx_sltosi(strtol(line, NULL, 10));
+ memset(tmpline, '\0', sizeof(tmpline));
+ memcpy(tmpline, line, (len == 5 ? 5 : 3));
+ *resp = curlx_sltosi(strtol(tmpline, NULL, 10));
/* Make sure real server never sends internal value */
if(*resp == 1)
--
2.22.0
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