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The argument to ctype functions must be EOF or representable as an
unsigned char.

Casting to int is particularly useless because that's what the
compiler already does. We need to prevent sign extension, not write
down that we want sign extension.

OK deraadt, millert, kn

/*	$Id: http.c,v 1.32 2022/12/14 18:32:26 florian Exp $ */
/*
 * Copyright (c) 2016 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/socket.h>

#include <arpa/inet.h>
#include <netinet/in.h>

#include <ctype.h>
#include <err.h>
#include <limits.h>
#include <netdb.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <tls.h>
#include <unistd.h>

#include "http.h"
#include "extern.h"

/*
 * A buffer for transferring HTTP/S data.
 */
struct	httpxfer {
	char		*hbuf;    /* header transfer buffer */
	size_t		 hbufsz;  /* header buffer size */
	int		 headok;  /* header has been parsed */
	char		*bbuf;    /* body transfer buffer */
	size_t		 bbufsz;  /* body buffer size */
	int		 bodyok;  /* body has been parsed */
	char		*headbuf; /* lookaside buffer for headers */
	struct httphead	*head;    /* parsed headers */
	size_t		 headsz;  /* number of headers */
};

/*
 * An HTTP/S connection object.
 */
struct	http {
	int		   fd;     /* connected socket */
	short		   port;   /* port number */
	struct source	   src;    /* endpoint (raw) host */
	char		  *path;   /* path to request */
	char		  *host;   /* name of endpoint host */
	struct tls	  *ctx;    /* if TLS */
	writefp		   writer; /* write function */
	readfp		   reader; /* read function */
};

struct tls_config *tlscfg;

static ssize_t
dosysread(char *buf, size_t sz, const struct http *http)
{
	ssize_t	 rc;

	rc = read(http->fd, buf, sz);
	if (rc == -1)
		warn("%s: read", http->src.ip);
	return rc;
}

static ssize_t
dosyswrite(const void *buf, size_t sz, const struct http *http)
{
	ssize_t	 rc;

	rc = write(http->fd, buf, sz);
	if (rc == -1)
		warn("%s: write", http->src.ip);
	return rc;
}

static ssize_t
dotlsread(char *buf, size_t sz, const struct http *http)
{
	ssize_t	 rc;

	do {
		rc = tls_read(http->ctx, buf, sz);
	} while (rc == TLS_WANT_POLLIN || rc == TLS_WANT_POLLOUT);

	if (rc == -1)
		warnx("%s: tls_read: %s", http->src.ip,
		    tls_error(http->ctx));
	return rc;
}

static ssize_t
dotlswrite(const void *buf, size_t sz, const struct http *http)
{
	ssize_t	 rc;

	do {
		rc = tls_write(http->ctx, buf, sz);
	} while (rc == TLS_WANT_POLLIN || rc == TLS_WANT_POLLOUT);

	if (rc == -1)
		warnx("%s: tls_write: %s", http->src.ip,
		    tls_error(http->ctx));
	return rc;
}

int
http_init(void)
{
	if (tlscfg != NULL)
		return 0;

	tlscfg = tls_config_new();
	if (tlscfg == NULL) {
		warn("tls_config_new");
		goto err;
	}

	if (tls_config_set_ca_file(tlscfg, tls_default_ca_cert_file()) == -1) {
		warn("tls_config_set_ca_file: %s", tls_config_error(tlscfg));
		goto err;
	}

	return 0;

 err:
	tls_config_free(tlscfg);
	tlscfg = NULL;

	return -1;
}

static ssize_t
http_read(char *buf, size_t sz, const struct http *http)
{
	ssize_t	 ssz, xfer;

	xfer = 0;
	do {
		if ((ssz = http->reader(buf, sz, http)) < 0)
			return -1;
		if (ssz == 0)
			break;
		xfer += ssz;
		sz -= ssz;
		buf += ssz;
	} while (ssz > 0 && sz > 0);

	return xfer;
}

static int
http_write(const char *buf, size_t sz, const struct http *http)
{
	ssize_t	 ssz, xfer;

	xfer = sz;
	while (sz > 0) {
		if ((ssz = http->writer(buf, sz, http)) < 0)
			return -1;
		sz -= ssz;
		buf += (size_t)ssz;
	}
	return xfer;
}

void
http_disconnect(struct http *http)
{
	int rc;

	if (http->ctx != NULL) {
		/* TLS connection. */
		do {
			rc = tls_close(http->ctx);
		} while (rc == TLS_WANT_POLLIN || rc == TLS_WANT_POLLOUT);

		tls_free(http->ctx);
	}
	if (http->fd != -1) {
		if (close(http->fd) == -1)
			warn("%s: close", http->src.ip);
	}

	http->fd = -1;
	http->ctx = NULL;
}

void
http_free(struct http *http)
{

	if (http == NULL)
		return;
	http_disconnect(http);
	free(http->host);
	free(http->path);
	free(http->src.ip);
	free(http);
}

struct http *
http_alloc(const struct source *addrs, size_t addrsz,
    const char *host, short port, const char *path)
{
	struct sockaddr_storage ss;
	int		 family, fd, c;
	socklen_t	 len;
	size_t		 cur, i = 0;
	struct http	*http;

	/* Do this while we still have addresses to connect. */
again:
	if (i == addrsz)
		return NULL;
	cur = i++;

	/* Convert to PF_INET or PF_INET6 address from string. */

	memset(&ss, 0, sizeof(struct sockaddr_storage));

	if (addrs[cur].family == 4) {
		family = PF_INET;
		((struct sockaddr_in *)&ss)->sin_family = AF_INET;
		((struct sockaddr_in *)&ss)->sin_port = htons(port);
		c = inet_pton(AF_INET, addrs[cur].ip,
		    &((struct sockaddr_in *)&ss)->sin_addr);
		len = sizeof(struct sockaddr_in);
	} else if (addrs[cur].family == 6) {
		family = PF_INET6;
		((struct sockaddr_in6 *)&ss)->sin6_family = AF_INET6;
		((struct sockaddr_in6 *)&ss)->sin6_port = htons(port);
		c = inet_pton(AF_INET6, addrs[cur].ip,
		    &((struct sockaddr_in6 *)&ss)->sin6_addr);
		len = sizeof(struct sockaddr_in6);
	} else {
		warnx("%s: unknown family", addrs[cur].ip);
		goto again;
	}

	if (c < 0) {
		warn("%s: inet_ntop", addrs[cur].ip);
		goto again;
	} else if (c == 0) {
		warnx("%s: inet_ntop", addrs[cur].ip);
		goto again;
	}

	/* Create socket and connect. */

	fd = socket(family, SOCK_STREAM, 0);
	if (fd == -1) {
		warn("%s: socket", addrs[cur].ip);
		goto again;
	} else if (connect(fd, (struct sockaddr *)&ss, len) == -1) {
		warn("%s: connect", addrs[cur].ip);
		close(fd);
		goto again;
	}

	/* Allocate the communicator. */

	http = calloc(1, sizeof(struct http));
	if (http == NULL) {
		warn("calloc");
		close(fd);
		return NULL;
	}
	http->fd = fd;
	http->port = port;
	http->src.family = addrs[cur].family;
	http->src.ip = strdup(addrs[cur].ip);
	http->host = strdup(host);
	http->path = strdup(path);
	if (http->src.ip == NULL || http->host == NULL || http->path == NULL) {
		warn("strdup");
		goto err;
	}

	/* If necessary, do our TLS setup. */

	if (port != 443) {
		http->writer = dosyswrite;
		http->reader = dosysread;
		return http;
	}

	http->writer = dotlswrite;
	http->reader = dotlsread;

	if ((http->ctx = tls_client()) == NULL) {
		warn("tls_client");
		goto err;
	} else if (tls_configure(http->ctx, tlscfg) == -1) {
		warnx("%s: tls_configure: %s",
			http->src.ip, tls_error(http->ctx));
		goto err;
	}

	if (tls_connect_socket(http->ctx, http->fd, http->host) != 0) {
		warnx("%s: tls_connect_socket: %s, %s", http->src.ip,
		    http->host, tls_error(http->ctx));
		goto err;
	}

	return http;
err:
	http_free(http);
	return NULL;
}

struct httpxfer *
http_open(const struct http *http, int headreq, const void *p, size_t psz)
{
	char		*req;
	int		 c;
	struct httpxfer	*trans;

	if (p == NULL) {
		if (headreq)
			c = asprintf(&req,
			    "HEAD %s HTTP/1.0\r\n"
			    "Host: %s\r\n"
			    "User-Agent: OpenBSD-acme-client\r\n"
			    "\r\n",
			    http->path, http->host);
		else
			c = asprintf(&req,
			    "GET %s HTTP/1.0\r\n"
			    "Host: %s\r\n"
			    "User-Agent: OpenBSD-acme-client\r\n"
			    "\r\n",
			    http->path, http->host);
	} else {
		c = asprintf(&req,
		    "POST %s HTTP/1.0\r\n"
		    "Host: %s\r\n"
		    "Content-Length: %zu\r\n"
		    "Content-Type: application/jose+json\r\n"
		    "User-Agent: OpenBSD-acme-client\r\n"
		    "\r\n",
		    http->path, http->host, psz);
	}

	if (c == -1) {
		warn("asprintf");
		return NULL;
	} else if (!http_write(req, c, http)) {
		free(req);
		return NULL;
	} else if (p != NULL && !http_write(p, psz, http)) {
		free(req);
		return NULL;
	}

	free(req);

	trans = calloc(1, sizeof(struct httpxfer));
	if (trans == NULL)
		warn("calloc");
	return trans;
}

void
http_close(struct httpxfer *x)
{

	if (x == NULL)
		return;
	free(x->hbuf);
	free(x->bbuf);
	free(x->headbuf);
	free(x->head);
	free(x);
}

/*
 * Read the HTTP body from the wire.
 * If invoked multiple times, this will return the same pointer with the
 * same data (or NULL, if the original invocation returned NULL).
 * Returns NULL if read or allocation errors occur.
 * You must not free the returned pointer.
 */
char *
http_body_read(const struct http *http, struct httpxfer *trans, size_t *sz)
{
	char		 buf[BUFSIZ];
	ssize_t		 ssz;
	void		*pp;
	size_t		 szp;

	if (sz == NULL)
		sz = &szp;

	/* Have we already parsed this? */

	if (trans->bodyok > 0) {
		*sz = trans->bbufsz;
		return trans->bbuf;
	} else if (trans->bodyok < 0)
		return NULL;

	*sz = 0;
	trans->bodyok = -1;

	do {
		/* If less than sizeof(buf), at EOF. */
		if ((ssz = http_read(buf, sizeof(buf), http)) < 0)
			return NULL;
		else if (ssz == 0)
			break;
		pp = recallocarray(trans->bbuf,
		    trans->bbufsz, trans->bbufsz + ssz, 1);
		if (pp == NULL) {
			warn("recallocarray");
			return NULL;
		}
		trans->bbuf = pp;
		memcpy(trans->bbuf + trans->bbufsz, buf, ssz);
		trans->bbufsz += ssz;
	} while (ssz == sizeof(buf));

	trans->bodyok = 1;
	*sz = trans->bbufsz;
	return trans->bbuf;
}

struct httphead *
http_head_get(const char *v, struct httphead *h, size_t hsz)
{
	size_t	 i;

	for (i = 0; i < hsz; i++) {
		if (strcasecmp(h[i].key, v) == 0)
			return &h[i];
	}
	return NULL;
}

/*
 * Look through the headers and determine our HTTP code.
 * This will return -1 on failure, otherwise the code.
 */
int
http_head_status(const struct http *http, struct httphead *h, size_t sz)
{
	int		 rc;
	unsigned int	 code;
	struct httphead *st;

	if ((st = http_head_get("Status", h, sz)) == NULL) {
		warnx("%s: no status header", http->src.ip);
		return -1;
	}

	rc = sscanf(st->val, "%*s %u %*s", &code);
	if (rc < 0) {
		warn("sscanf");
		return -1;
	} else if (rc != 1) {
		warnx("%s: cannot convert status header", http->src.ip);
		return -1;
	}
	return code;
}

/*
 * Parse headers from the transfer.
 * Malformed headers are skipped.
 * A special "Status" header is added for the HTTP status line.
 * This can only happen once http_head_read has been called with
 * success.
 * This can be invoked multiple times: it will only parse the headers
 * once and after that it will just return the cache.
 * You must not free the returned pointer.
 * If the original header parse failed, or if memory allocation fails
 * internally, this returns NULL.
 */
struct httphead *
http_head_parse(const struct http *http, struct httpxfer *trans, size_t *sz)
{
	size_t		 hsz, szp;
	struct httphead	*h;
	char		*cp, *ep, *ccp, *buf;

	if (sz == NULL)
		sz = &szp;

	/*
	 * If we've already parsed the headers, return the
	 * previously-parsed buffer now.
	 * If we have errors on the stream, return NULL now.
	 */

	if (trans->head != NULL) {
		*sz = trans->headsz;
		return trans->head;
	} else if (trans->headok <= 0)
		return NULL;

	if ((buf = strdup(trans->hbuf)) == NULL) {
		warn("strdup");
		return NULL;
	}
	hsz = 0;
	cp = buf;

	do {
		if ((cp = strstr(cp, "\r\n")) != NULL)
			cp += 2;
		hsz++;
	} while (cp != NULL);

	/*
	 * Allocate headers, then step through the data buffer, parsing
	 * out headers as we have them.
	 * We know at this point that the buffer is NUL-terminated in
	 * the usual way.
	 */

	h = calloc(hsz, sizeof(struct httphead));
	if (h == NULL) {
		warn("calloc");
		free(buf);
		return NULL;
	}

	*sz = hsz;
	hsz = 0;
	cp = buf;

	do {
		if ((ep = strstr(cp, "\r\n")) != NULL) {
			*ep = '\0';
			ep += 2;
		}
		if (hsz == 0) {
			h[hsz].key = "Status";
			h[hsz++].val = cp;
			continue;
		}

		/* Skip bad headers. */
		if ((ccp = strchr(cp, ':')) == NULL) {
			warnx("%s: header without separator", http->src.ip);
			continue;
		}

		*ccp++ = '\0';
		while (isspace((unsigned char)*ccp))
			ccp++;
		h[hsz].key = cp;
		h[hsz++].val = ccp;
	} while ((cp = ep) != NULL);

	trans->headbuf = buf;
	trans->head = h;
	trans->headsz = hsz;
	return h;
}

/*
 * Read the HTTP headers from the wire.
 * If invoked multiple times, this will return the same pointer with the
 * same data (or NULL, if the original invocation returned NULL).
 * Returns NULL if read or allocation errors occur.
 * You must not free the returned pointer.
 */
char *
http_head_read(const struct http *http, struct httpxfer *trans, size_t *sz)
{
	char		 buf[BUFSIZ];
	ssize_t		 ssz;
	char		*ep;
	void		*pp;
	size_t		 szp;

	if (sz == NULL)
		sz = &szp;

	/* Have we already parsed this? */

	if (trans->headok > 0) {
		*sz = trans->hbufsz;
		return trans->hbuf;
	} else if (trans->headok < 0)
		return NULL;

	*sz = 0;
	ep = NULL;
	trans->headok = -1;

	/*
	 * Begin by reading by BUFSIZ blocks until we reach the header
	 * termination marker (two CRLFs).
	 * We might read into our body, but that's ok: we'll copy out
	 * the body parts into our body buffer afterward.
	 */

	do {
		/* If less than sizeof(buf), at EOF. */
		if ((ssz = http_read(buf, sizeof(buf), http)) < 0)
			return NULL;
		else if (ssz == 0)
			break;
		pp = recallocarray(trans->hbuf,
		    trans->hbufsz, trans->hbufsz + ssz, 1);
		if (pp == NULL) {
			warn("recallocarray");
			return NULL;
		}
		trans->hbuf = pp;
		memcpy(trans->hbuf + trans->hbufsz, buf, ssz);
		trans->hbufsz += ssz;
		/* Search for end of headers marker. */
		ep = memmem(trans->hbuf, trans->hbufsz, "\r\n\r\n", 4);
	} while (ep == NULL && ssz == sizeof(buf));

	if (ep == NULL) {
		warnx("%s: partial transfer", http->src.ip);
		return NULL;
	}
	*ep = '\0';

	/*
	 * The header data is invalid if it has any binary characters in
	 * it: check that now.
	 * This is important because we want to guarantee that all
	 * header keys and pairs are properly NUL-terminated.
	 */

	if (strlen(trans->hbuf) != (uintptr_t)(ep - trans->hbuf)) {
		warnx("%s: binary data in header", http->src.ip);
		return NULL;
	}

	/*
	 * Copy remaining buffer into body buffer.
	 */

	ep += 4;
	trans->bbufsz = (trans->hbuf + trans->hbufsz) - ep;
	trans->bbuf = malloc(trans->bbufsz);
	if (trans->bbuf == NULL) {
		warn("malloc");
		return NULL;
	}
	memcpy(trans->bbuf, ep, trans->bbufsz);

	trans->headok = 1;
	*sz = trans->hbufsz;
	return trans->hbuf;
}

void
http_get_free(struct httpget *g)
{

	if (g == NULL)
		return;
	http_close(g->xfer);
	http_free(g->http);
	free(g);
}

struct httpget *
http_get(const struct source *addrs, size_t addrsz, const char *domain,
    short port, const char *path, int headreq, const void *post, size_t postsz)
{
	struct http	*h;
	struct httpxfer	*x;
	struct httpget	*g;
	struct httphead	*head;
	size_t		 headsz, bodsz, headrsz;
	int		 code;
	char		*bod, *headr;

	h = http_alloc(addrs, addrsz, domain, port, path);
	if (h == NULL)
		return NULL;

	if ((x = http_open(h, headreq, post, postsz)) == NULL) {
		http_free(h);
		return NULL;
	} else if ((headr = http_head_read(h, x, &headrsz)) == NULL) {
		http_close(x);
		http_free(h);
		return NULL;
	} else if ((bod = http_body_read(h, x, &bodsz)) == NULL) {
		http_close(x);
		http_free(h);
		return NULL;
	}

	http_disconnect(h);

	if ((head = http_head_parse(h, x, &headsz)) == NULL) {
		http_close(x);
		http_free(h);
		return NULL;
	} else if ((code = http_head_status(h, head, headsz)) < 0) {
		http_close(x);
		http_free(h);
		return NULL;
	}

	if ((g = calloc(1, sizeof(struct httpget))) == NULL) {
		warn("calloc");
		http_close(x);
		http_free(h);
		return NULL;
	}

	g->headpart = headr;
	g->headpartsz = headrsz;
	g->bodypart = bod;
	g->bodypartsz = bodsz;
	g->head = head;
	g->headsz = headsz;
	g->code = code;
	g->xfer = x;
	g->http = h;
	return g;
}