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libwebsockets/lib/tls/tls.c
Andy Green c9731c5f17 type comparisons: fixes
This is a huge patch that should be a global NOP.

For unix type platforms it enables -Wconversion to issue warnings (-> error)
for all automatic casts that seem less than ideal but are normally concealed
by the toolchain.

This is things like passing an int to a size_t argument.  Once enabled, I
went through all args on my default build (which build most things) and
tried to make the removed default cast explicit.

With that approach it neither change nor bloat the code, since it compiles
to whatever it was doing before, just with the casts made explicit... in a
few cases I changed some length args from int to size_t but largely left
the causes alone.

From now on, new code that is relying on less than ideal casting
will complain and nudge me to improve it by warnings.
2021-01-05 10:56:38 +00:00

456 lines
10 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "private-lib-core.h"
#include "private-lib-tls.h"
#if defined(LWS_WITH_NETWORK)
#if defined(LWS_WITH_MBEDTLS) || (defined(OPENSSL_VERSION_NUMBER) && \
OPENSSL_VERSION_NUMBER >= 0x10002000L)
static int
alpn_cb(SSL *s, const unsigned char **out, unsigned char *outlen,
const unsigned char *in, unsigned int inlen, void *arg)
{
#if !defined(LWS_WITH_MBEDTLS)
struct alpn_ctx *alpn_ctx = (struct alpn_ctx *)arg;
if (SSL_select_next_proto((unsigned char **)out, outlen, alpn_ctx->data,
alpn_ctx->len, in, inlen) !=
OPENSSL_NPN_NEGOTIATED)
return SSL_TLSEXT_ERR_NOACK;
#endif
return SSL_TLSEXT_ERR_OK;
}
#endif
int
lws_tls_restrict_borrow(struct lws_context *context)
{
if (!context->simultaneous_ssl_restriction)
return 0;
if (context->simultaneous_ssl >= context->simultaneous_ssl_restriction) {
lwsl_notice("%s: tls connection limit %d\n", __func__,
context->simultaneous_ssl);
return 1;
}
if (++context->simultaneous_ssl == context->simultaneous_ssl_restriction)
/* that was the last allowed SSL connection */
lws_gate_accepts(context, 0);
lwsl_info("%s: %d -> %d\n", __func__,
context->simultaneous_ssl - 1,
context->simultaneous_ssl);
return 0;
}
void
lws_tls_restrict_return(struct lws_context *context)
{
if (context->simultaneous_ssl_restriction) {
if (context->simultaneous_ssl-- ==
context->simultaneous_ssl_restriction)
/* we made space and can do an accept */
lws_gate_accepts(context, 1);
lwsl_info("%s: %d -> %d\n", __func__,
context->simultaneous_ssl + 1,
context->simultaneous_ssl);
}
}
void
lws_context_init_alpn(struct lws_vhost *vhost)
{
#if defined(LWS_WITH_MBEDTLS) || (defined(OPENSSL_VERSION_NUMBER) && \
OPENSSL_VERSION_NUMBER >= 0x10002000L)
const char *alpn_comma = vhost->context->tls.alpn_default;
if (vhost->tls.alpn)
alpn_comma = vhost->tls.alpn;
lwsl_info(" Server '%s' advertising ALPN: %s\n",
vhost->name, alpn_comma);
vhost->tls.alpn_ctx.len = (uint8_t)lws_alpn_comma_to_openssl(alpn_comma,
vhost->tls.alpn_ctx.data,
sizeof(vhost->tls.alpn_ctx.data) - 1);
SSL_CTX_set_alpn_select_cb(vhost->tls.ssl_ctx, alpn_cb,
&vhost->tls.alpn_ctx);
#else
lwsl_err(
" HTTP2 / ALPN configured but not supported by OpenSSL 0x%lx\n",
OPENSSL_VERSION_NUMBER);
#endif // OPENSSL_VERSION_NUMBER >= 0x10002000L
}
int
lws_tls_server_conn_alpn(struct lws *wsi)
{
#if defined(LWS_WITH_MBEDTLS) || (defined(OPENSSL_VERSION_NUMBER) && \
OPENSSL_VERSION_NUMBER >= 0x10002000L)
const unsigned char *name = NULL;
char cstr[10];
unsigned len;
if (!wsi->tls.ssl)
return 0;
SSL_get0_alpn_selected(wsi->tls.ssl, &name, &len);
if (!len) {
lwsl_info("no ALPN upgrade\n");
return 0;
}
if (len > sizeof(cstr) - 1)
len = sizeof(cstr) - 1;
memcpy(cstr, name, len);
cstr[len] = '\0';
lwsl_info("negotiated '%s' using ALPN\n", cstr);
wsi->tls.use_ssl |= LCCSCF_USE_SSL;
return lws_role_call_alpn_negotiated(wsi, (const char *)cstr);
#endif // OPENSSL_VERSION_NUMBER >= 0x10002000L
return 0;
}
#endif
#if !defined(LWS_PLAT_OPTEE) && !defined(OPTEE_DEV_KIT)
#if defined(LWS_PLAT_FREERTOS) && !defined(LWS_AMAZON_RTOS)
int alloc_file(struct lws_context *context, const char *filename, uint8_t **buf,
lws_filepos_t *amount)
{
nvs_handle nvh;
size_t s;
int n = 0;
ESP_ERROR_CHECK(nvs_open("lws-station", NVS_READWRITE, &nvh));
if (nvs_get_blob(nvh, filename, NULL, &s) != ESP_OK) {
n = 1;
goto bail;
}
*buf = lws_malloc(s + 1, "alloc_file");
if (!*buf) {
n = 2;
goto bail;
}
if (nvs_get_blob(nvh, filename, (char *)*buf, &s) != ESP_OK) {
lws_free(*buf);
n = 1;
goto bail;
}
*amount = s;
(*buf)[s] = '\0';
lwsl_notice("%s: nvs: read %s, %d bytes\n", __func__, filename, (int)s);
bail:
nvs_close(nvh);
return n;
}
#else
int alloc_file(struct lws_context *context, const char *filename, uint8_t **buf,
lws_filepos_t *amount)
{
FILE *f;
size_t s;
ssize_t m;
int n = 0;
f = fopen(filename, "rb");
if (f == NULL) {
n = 1;
goto bail;
}
if (fseek(f, 0, SEEK_END) != 0) {
n = 1;
goto bail;
}
m = ftell(f);
if (m == -1l) {
n = 1;
goto bail;
}
s = (size_t)m;
if (fseek(f, 0, SEEK_SET) != 0) {
n = 1;
goto bail;
}
*buf = lws_malloc(s, "alloc_file");
if (!*buf) {
n = 2;
goto bail;
}
if (fread(*buf, s, 1, f) != 1) {
lws_free(*buf);
n = 1;
goto bail;
}
*amount = s;
bail:
if (f)
fclose(f);
return n;
}
#endif
/*
* filename: NULL means use buffer inbuf length inlen directly, otherwise
* load the file "filename" into an allocated buffer.
*
* Allocates a separate DER output buffer if inbuf / inlen are the input,
* since the
*
* Contents may be PEM or DER: returns with buf pointing to DER and amount
* set to the DER length.
*/
int
lws_tls_alloc_pem_to_der_file(struct lws_context *context, const char *filename,
const char *inbuf, lws_filepos_t inlen,
uint8_t **buf, lws_filepos_t *amount)
{
uint8_t *pem = NULL, *p, *end, *opem;
lws_filepos_t len;
uint8_t *q;
int n;
if (filename) {
n = alloc_file(context, filename, (uint8_t **)&pem, &len);
if (n)
return n;
} else {
pem = (uint8_t *)inbuf;
len = inlen;
}
opem = p = pem;
end = p + len;
if (strncmp((char *)p, "-----", 5)) {
/* take it as being already DER */
pem = lws_malloc((size_t)inlen, "alloc_der");
if (!pem)
return 1;
memcpy(pem, inbuf, (size_t)inlen);
*buf = pem;
*amount = inlen;
return 0;
}
/* PEM -> DER */
if (!filename) {
/* we don't know if it's in const memory... alloc the output */
pem = lws_malloc(((size_t)inlen * 3) / 4, "alloc_der");
if (!pem) {
lwsl_err("a\n");
return 1;
}
} /* else overwrite the allocated, b64 input with decoded DER */
/* trim the first line */
p += 5;
while (p < end && *p != '\n' && *p != '-')
p++;
if (*p != '-') {
lwsl_err("b\n");
goto bail;
}
while (p < end && *p != '\n')
p++;
if (p >= end) {
lwsl_err("c\n");
goto bail;
}
p++;
/* trim the last line */
q = (uint8_t *)end - 2;
while (q > opem && *q != '\n')
q--;
if (*q != '\n') {
lwsl_err("d\n");
goto bail;
}
/* we can't write into the input buffer for mem, since it may be in RO
* const segment
*/
if (filename)
*q = '\0';
*amount = (unsigned int)lws_b64_decode_string_len((char *)p, lws_ptr_diff(q, p),
(char *)pem, (int)(long long)len);
*buf = (uint8_t *)pem;
return 0;
bail:
lws_free((uint8_t *)pem);
return 4;
}
#endif
#if !defined(LWS_PLAT_FREERTOS) && !defined(LWS_PLAT_OPTEE) && !defined(OPTEE_DEV_KIT)
static int
lws_tls_extant(const char *name)
{
/* it exists if we can open it... */
int fd = open(name, O_RDONLY);
char buf[1];
ssize_t n;
if (fd < 0)
return 1;
/* and we can read at least one byte out of it */
n = read(fd, buf, 1);
close(fd);
return n != 1;
}
#endif
/*
* Returns 0 if the filepath "name" exists and can be read from.
*
* In addition, if "name".upd exists, backup "name" to "name.old.1"
* and rename "name".upd to "name" before reporting its existence.
*
* There are four situations and three results possible:
*
* 1) LWS_TLS_EXTANT_NO: There are no certs at all (we are waiting for them to
* be provisioned). We also feel like this if we need privs we don't have
* any more to look in the directory.
*
* 2) There are provisioned certs written (xxx.upd) and we still have root
* privs... in this case we rename any existing cert to have a backup name
* and move the upd cert into place with the correct name. This then becomes
* situation 4 for the caller.
*
* 3) LWS_TLS_EXTANT_ALTERNATIVE: There are provisioned certs written (xxx.upd)
* but we no longer have the privs needed to read or rename them. In this
* case, indicate that the caller should use temp copies if any we do have
* rights to access. This is normal after we have updated the cert.
*
* But if we dropped privs, we can't detect the provisioned xxx.upd cert +
* key, because we can't see in the dir. So we have to upgrade NO to
* ALTERNATIVE when we actually have the in-memory alternative.
*
* 4) LWS_TLS_EXTANT_YES: The certs are present with the correct name and we
* have the rights to read them.
*/
enum lws_tls_extant
lws_tls_use_any_upgrade_check_extant(const char *name)
{
#if !defined(LWS_PLAT_OPTEE) && !defined(LWS_AMAZON_RTOS)
int n;
#if !defined(LWS_PLAT_FREERTOS)
char buf[256];
lws_snprintf(buf, sizeof(buf) - 1, "%s.upd", name);
if (!lws_tls_extant(buf)) {
/* ah there is an updated file... how about the desired file? */
if (!lws_tls_extant(name)) {
/* rename the desired file */
for (n = 0; n < 50; n++) {
lws_snprintf(buf, sizeof(buf) - 1,
"%s.old.%d", name, n);
if (!rename(name, buf))
break;
}
if (n == 50) {
lwsl_notice("unable to rename %s\n", name);
return LWS_TLS_EXTANT_ALTERNATIVE;
}
lws_snprintf(buf, sizeof(buf) - 1, "%s.upd", name);
}
/* desired file is out of the way, rename the updated file */
if (rename(buf, name)) {
lwsl_notice("unable to rename %s to %s\n", buf, name);
return LWS_TLS_EXTANT_ALTERNATIVE;
}
}
if (lws_tls_extant(name))
return LWS_TLS_EXTANT_NO;
#else
nvs_handle nvh;
size_t s = 8192;
if (nvs_open("lws-station", NVS_READWRITE, &nvh)) {
lwsl_notice("%s: can't open nvs\n", __func__);
return LWS_TLS_EXTANT_NO;
}
n = nvs_get_blob(nvh, name, NULL, &s);
nvs_close(nvh);
if (n)
return LWS_TLS_EXTANT_NO;
#endif
#endif
return LWS_TLS_EXTANT_YES;
}