From 3b6431eb9c9dba603385f70a2131ab4a01bf0d3b Mon Sep 17 00:00:00 2001 From: Yann Ylavic Date: Mon, 18 Jan 2021 17:39:12 +0000 Subject: [PATCH] Merge r1885659 from trunk: mod_auth_digest: Fast validation of the nonce's base64 to fail early if the format can't match anyway. Submitted by: ylavic Reviewed by: ylavic, covener, jailletc36 git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1885666 13f79535-47bb-0310-9956-ffa450edef68 Upstream-Status: Backport CVE: CVE-2020-35452 Reference to upstream patch: https://security-tracker.debian.org/tracker/CVE-2020-35452 https://github.com/apache/httpd/commit/3b6431eb9c9dba603385f70a2131ab4a01bf0d3b Signed-off-by: Li Wang --- modules/aaa/mod_auth_digest.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/modules/aaa/mod_auth_digest.c b/modules/aaa/mod_auth_digest.c index b760941..0825b1b 100644 --- a/modules/aaa/mod_auth_digest.c +++ b/modules/aaa/mod_auth_digest.c @@ -1422,9 +1422,14 @@ static int check_nonce(request_rec *r, digest_header_rec *resp, time_rec nonce_time; char tmp, hash[NONCE_HASH_LEN+1]; - if (strlen(resp->nonce) != NONCE_LEN) { + /* Since the time part of the nonce is a base64 encoding of an + * apr_time_t (8 bytes), it should end with a '=', fail early otherwise. + */ + if (strlen(resp->nonce) != NONCE_LEN + || resp->nonce[NONCE_TIME_LEN - 1] != '=') { ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01775) - "invalid nonce %s received - length is not %d", + "invalid nonce '%s' received - length is not %d " + "or time encoding is incorrect", resp->nonce, NONCE_LEN); note_digest_auth_failure(r, conf, resp, 1); return HTTP_UNAUTHORIZED; -- 2.7.4