Hi, from nginx-dev list. SSL: workaround for incorrect SSL_write() errors in OpenSSL 1.1.1. OpenSSL 1.1.1 fails to return SSL_ERROR_SYSCALL if an error happens during SSL_write() after close_notify alert from the peer, and returns SSL_ERROR_ZERO_RETURN instead. Broken by this commit, which removes the "i == 0" check around the SSL_RECEIVED_SHUTDOWN one: https://git.openssl.org/?p=openssl.git;a=commitdiff;h=8051ab2 In particular, if a client closed the connection without reading the response but with properly sent close_notify alert, this resulted in unexpected "SSL_write() failed while ..." critical log message instead of correct "SSL_write() failed (32: Broken pipe)" at the info level. Since SSL_ERROR_ZERO_RETURN cannot be legitimately returned after SSL_write(), the fix is to convert all SSL_ERROR_ZERO_RETURN errors after SSL_write() to SSL_ERROR_SYSCALL. diffstat: src/event/ngx_event_openssl.c | 12 ++++++++++++ 1 files changed, 12 insertions(+), 0 deletions(-) diffs (22 lines): diff -r 3781de64e747 -r 61011bfcdb49 src/event/ngx_event_openssl.c --- a/src/event/ngx_event_openssl.c Wed Sep 09 19:26:27 2020 +0300 +++ b/src/event/ngx_event_openssl.c Wed Sep 16 18:26:22 2020 +0300 @@ -2573,6 +2573,18 @@ ngx_ssl_write(ngx_connection_t *c, u_cha sslerr = SSL_get_error(c->ssl->connection, n); + if (sslerr == SSL_ERROR_ZERO_RETURN) { + + /* + * OpenSSL 1.1.1 fails to return SSL_ERROR_SYSCALL if an error + * happens during SSL_write() after close_notify alert from the + * peer, and returns SSL_ERROR_ZERO_RETURN instead, + * https://git.openssl.org/?p=openssl.git;a=commitdiff;h=8051ab2 + */ + + sslerr = SSL_ERROR_SYSCALL; + } + regards, Ranier Vilela
