From bbb71507b7bab52002f9b1e0880bed6a32834511 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Fri, 23 Apr 2021 10:54:10 +0200 Subject: [PATCH] schannel: don't use static to store selected ciphers CVE-2021-22897 Bug: https://curl.se/docs/CVE-2021-22897.html --- lib/vtls/schannel.c | 9 +++++---- lib/vtls/schannel.h | 3 +++ 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/lib/vtls/schannel.c b/lib/vtls/schannel.c index 8c25ac5dd5a5..dba7072273a9 100644 --- a/lib/vtls/schannel.c +++ b/lib/vtls/schannel.c @@ -328,12 +328,12 @@ get_alg_id_by_name(char *name) } static CURLcode -set_ssl_ciphers(SCHANNEL_CRED *schannel_cred, char *ciphers) +set_ssl_ciphers(SCHANNEL_CRED *schannel_cred, char *ciphers, + int *algIds) { char *startCur = ciphers; int algCount = 0; - static ALG_ID algIds[45]; /*There are 45 listed in the MS headers*/ - while(startCur && (0 != *startCur) && (algCount < 45)) { + while(startCur && (0 != *startCur) && (algCount < NUMOF_CIPHERS)) { long alg = strtol(startCur, 0, 0); if(!alg) alg = get_alg_id_by_name(startCur); @@ -593,7 +593,8 @@ schannel_connect_step1(struct Curl_easy *data, struct connectdata *conn, } if(SSL_CONN_CONFIG(cipher_list)) { - result = set_ssl_ciphers(&schannel_cred, SSL_CONN_CONFIG(cipher_list)); + result = set_ssl_ciphers(&schannel_cred, SSL_CONN_CONFIG(cipher_list), + BACKEND->algIds); if(CURLE_OK != result) { failf(data, "Unable to set ciphers to passed via SSL_CONN_CONFIG"); return result; diff --git a/lib/vtls/schannel.h b/lib/vtls/schannel.h index 2952caa1a5a1..77853aa30f96 100644 --- a/lib/vtls/schannel.h +++ b/lib/vtls/schannel.h @@ -71,6 +71,8 @@ CURLcode Curl_verify_certificate(struct Curl_easy *data, #endif #endif +#define NUMOF_CIPHERS 45 /* There are 45 listed in the MS headers */ + struct Curl_schannel_cred { CredHandle cred_handle; TimeStamp time_stamp; @@ -102,6 +104,7 @@ struct ssl_backend_data { #ifdef HAS_MANUAL_VERIFY_API bool use_manual_cred_validation; /* true if manual cred validation is used */ #endif + ALG_ID algIds[NUMOF_CIPHERS]; }; #endif /* EXPOSE_SCHANNEL_INTERNAL_STRUCTS */