diff options
| author | Eldar Zaitov <kyprizel@volema.com> | 2013-01-30 23:22:27 +0100 |
|---|---|---|
| committer | Daniel Stenberg <daniel@haxx.se> | 2013-02-06 11:06:33 +0100 |
| commit | f206d6c055d1008f0edb6d5d5920f0f300b9983a (patch) | |
| tree | f882b5787378cb8e4c1d9cf2c9944c24a454c465 /lib/curl_sasl.c | |
| parent | add37cc49f241212bc29d19f9f80700458df6794 (diff) | |
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
Diffstat (limited to 'lib/curl_sasl.c')
| -rw-r--r-- | lib/curl_sasl.c | 23 |
1 files changed, 6 insertions, 17 deletions
diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c index 57116b651..d07387d47 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); |