From a94973805df96269bf3f3bf0a20ccb9887313316 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Wed, 9 Oct 2024 10:04:35 +0200 Subject: [PATCH] hsts: improve subdomain handling - on load, only replace existing HSTS entries if there is a full host match - on matching, prefer a full host match and secondary the longest tail subdomain match Closes #15210 CVE: CVE-2024-9681 Upstream-Status: Backport [https://github.com/curl/curl/commit/a94973805df96269bf3f3bf0a20ccb9887313316] Signed-off-by: Peter Marko --- lib/hsts.c | 14 ++++++++++---- tests/data/test1660 | 2 +- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/lib/hsts.c b/lib/hsts.c index d5e883f51ef0f7..12052ce53c1c5a 100644 --- a/lib/hsts.c +++ b/lib/hsts.c @@ -254,12 +254,14 @@ CURLcode Curl_hsts_parse(struct hsts *h, const char *hostname, struct stsentry *Curl_hsts(struct hsts *h, const char *hostname, bool subdomain) { + struct stsentry *bestsub = NULL; if(h) { char buffer[MAX_HSTS_HOSTLEN + 1]; time_t now = time(NULL); size_t hlen = strlen(hostname); struct Curl_llist_element *e; struct Curl_llist_element *n; + size_t blen = 0; if((hlen > MAX_HSTS_HOSTLEN) || !hlen) return NULL; @@ -284,15 +286,19 @@ struct stsentry *Curl_hsts(struct hsts *h, const char *hostname, if(ntail < hlen) { size_t offs = hlen - ntail; if((hostname[offs-1] == '.') && - strncasecompare(&hostname[offs], sts->host, ntail)) - return sts; + strncasecompare(&hostname[offs], sts->host, ntail) && + (ntail > blen)) { + /* save the tail match with the longest tail */ + bestsub = sts; + blen = ntail; + } } } if(strcasecompare(hostname, sts->host)) return sts; } } - return NULL; /* no match */ + return bestsub; } /* @@ -444,7 +450,7 @@ static CURLcode hsts_add(struct hsts *h, char *line) e = Curl_hsts(h, p, subdomain); if(!e) result = hsts_create(h, p, subdomain, expires); - else { + else if(strcasecompare(p, e->host)) { /* the same host name, use the largest expire time */ if(expires > e->expires) e->expires = expires; diff --git a/tests/data/test1660 b/tests/data/test1660 index f86126d19cf269..4b6f9615c9d517 100644 --- a/tests/data/test1660 +++ b/tests/data/test1660 @@ -52,7 +52,7 @@ this.example [this.example]: 1548400797 Input 12: error 43 Input 13: error 43 Input 14: error 43 -3.example.com [example.com]: 1569905261 includeSubDomains +3.example.com [3.example.com]: 1569905261 includeSubDomains 3.example.com [example.com]: 1569905261 includeSubDomains foo.example.com [example.com]: 1569905261 includeSubDomains 'foo.xample.com' is not HSTS