Attachment 691585 Details for Bug 906779 – Proposed upstream patch to correct this issue

[patch] Proposed upstream patch to correct this issue

curl-sasl.patch (text/plain), 2.41 KB, created by Jan Lieskovsky on 2013-02-01 13:34:32 UTC

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Creator: Jan Lieskovsky

Created: 2013-02-01 13:34:32 UTC

Size: 2.41 KB

patch

obsolete

>From ee45a34907ffeb5fd95b0513040d8491d565b663 Mon Sep 17 00:00:00 2001
>From: Eldar Zaitov <kyprizel@volema.com>
>Date: Wed, 30 Jan 2013 23:22:27 +0100
>Subject: [PATCH] Curl_sasl_create_digest_md5_message: fix buffer overflow
>
>When negotiating SASL DIGEST-MD5 authentication, the function
>Curl_sasl_create_digest_md5_message() uses the data provided from the
>server without doing the proper length checks and that data is then
>appended to a local fixed-size buffer on the stack.
>
>This vulnerability can be exploited by someone who is in control of a
>server that a libcurl based program is accessing with POP3, SMTP or
>IMAP. For applications that accept user provided URLs, it is also
>thinkable that a malicious user would feed an application with a URL to
>a server hosting code targetting this flaw.
>
>Bug: http://curl.haxx.se/docs/adv_20130206.html
>---
> lib/curl_sasl.c |   23 ++++++-----------------
> 1 file changed, 6 insertions(+), 17 deletions(-)
>
>diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c
>index 57116b6..d07387d 100644
>--- a/lib/curl_sasl.c
>+++ b/lib/curl_sasl.c
>@@ -346,9 +346,7 @@ CURLcode Curl_sasl_create_digest_md5_message(struct SessionHandle *data,
>     snprintf(&HA1_hex[2 * i], 3, "%02x", digest[i]);
> 
>   /* Prepare the URL string */
>-  strcpy(uri, service);
>-  strcat(uri, "/");
>-  strcat(uri, realm);
>+  snprintf(uri, sizeof(uri), "%s/%s", service, realm);
> 
>   /* Calculate H(A2) */
>   ctxt = Curl_MD5_init(Curl_DIGEST_MD5);
>@@ -392,20 +390,11 @@ CURLcode Curl_sasl_create_digest_md5_message(struct SessionHandle *data,
>   for(i = 0; i < MD5_DIGEST_LEN; i++)
>     snprintf(&resp_hash_hex[2 * i], 3, "%02x", digest[i]);
> 
>-  strcpy(response, "username=\"");
>-  strcat(response, userp);
>-  strcat(response, "\",realm=\"");
>-  strcat(response, realm);
>-  strcat(response, "\",nonce=\"");
>-  strcat(response, nonce);
>-  strcat(response, "\",cnonce=\"");
>-  strcat(response, cnonce);
>-  strcat(response, "\",nc=");
>-  strcat(response, nonceCount);
>-  strcat(response, ",digest-uri=\"");
>-  strcat(response, uri);
>-  strcat(response, "\",response=");
>-  strcat(response, resp_hash_hex);
>+  snprintf(response, sizeof(response),
>+           "username=\"%s\",realm=\"%s\",nonce=\"%s\","
>+           "cnonce=\"%s\",nc=\"%s\",digest-uri=\"%s\",response=%s",
>+           userp, realm, nonce,
>+           cnonce, nonceCount, uri, resp_hash_hex);
> 
>   /* Base64 encode the reply */
>   return Curl_base64_encode(data, response, 0, outptr, outlen);
>-- 
>1.7.10.4
>

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Attachments on bug 906779: 691585