Subject: [PATCH] telnet: fix option parser to not send uninitialized
contents CVE-2021-22925
Reported-by: Red Hat Product Security
Bug: https://curl.se/docs/CVE-2021-22925.html
CVE: CVE-2021-22925
Upstream-Status: backport from Ubuntu curl_7.68.0-1ubuntu2.6
Signed-off-by: Mike Crowe <mac@mcrowe.com>
---
lib/telnet.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/lib/telnet.c b/lib/telnet.c
index 4bf4c652c..3347ad6d1 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -967,12 +967,17 @@ static void suboption(struct connectdata *conn)
size_t tmplen = (strlen(v->data) + 1);
/* Add the variable only if it fits */
if(len + tmplen < (int)sizeof(temp)-6) {
- if(sscanf(v->data, "%127[^,],%127s", varname, varval) == 2) {
- msnprintf((char *)&temp[len], sizeof(temp) - len,
- "%c%s%c%s", CURL_NEW_ENV_VAR, varname,
- CURL_NEW_ENV_VALUE, varval);
- len += tmplen;
- }
+ int rv;
+ char sep[2] = "";
+ varval[0] = 0;
+ rv = sscanf(v->data, "%127[^,]%1[,]%127s", varname, sep, varval);
+ if(rv == 1)
+ len += msnprintf((char *)&temp[len], sizeof(temp) - len,
+ "%c%s", CURL_NEW_ENV_VAR, varname);
+ else if(rv >= 2)
+ len += msnprintf((char *)&temp[len], sizeof(temp) - len,
+ "%c%s%c%s", CURL_NEW_ENV_VAR, varname,
+ CURL_NEW_ENV_VALUE, varval);
}
}
msnprintf((char *)&temp[len], sizeof(temp) - len,
--
2.30.2