1 files changed, 199 insertions, 318 deletions

diff --git a/imap-send.c b/imap-send.c
index d42e471297..d6b65e204c 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -29,50 +29,20 @@
 #ifdef NO_OPENSSL
 typedef void *SSL;
 #else
+#ifdef APPLE_COMMON_CRYPTO
+#include <CommonCrypto/CommonHMAC.h>
+#define HMAC_CTX CCHmacContext
+#define HMAC_Init(hmac, key, len, algo) CCHmacInit(hmac, algo, key, len)
+#define HMAC_Update CCHmacUpdate
+#define HMAC_Final(hmac, hash, ptr) CCHmacFinal(hmac, hash)
+#define HMAC_CTX_cleanup(ignore)
+#define EVP_md5() kCCHmacAlgMD5
+#else
 #include <openssl/evp.h>
 #include <openssl/hmac.h>
 #endif
-
-struct store_conf {
-	char *name;
-	const char *path; /* should this be here? its interpretation is driver-specific */
-	char *map_inbox;
-	char *trash;
-	unsigned max_size; /* off_t is overkill */
-	unsigned trash_remote_new:1, trash_only_new:1;
-};
-
-/* For message->status */
-#define M_RECENT       (1<<0) /* unsyncable flag; maildir_* depend on this being 1<<0 */
-#define M_DEAD         (1<<1) /* expunged */
-#define M_FLAGS        (1<<2) /* flags fetched */
-
-struct message {
-	struct message *next;
-	size_t size; /* zero implies "not fetched" */
-	int uid;
-	unsigned char flags, status;
-};
-
-struct store {
-	struct store_conf *conf; /* foreign */
-
-	/* currently open mailbox */
-	const char *name; /* foreign! maybe preset? */
-	char *path; /* own */
-	struct message *msgs; /* own */
-	int uidvalidity;
-	unsigned char opts; /* maybe preset? */
-	/* note that the following do _not_ reflect stats from msgs, but mailbox totals */
-	int count; /* # of messages */
-	int recent; /* # of recent messages - don't trust this beyond the initial read */
-};
-
-struct msg_data {
-	char *data;
-	int len;
-	unsigned char flags;
-};
+#include <openssl/x509v3.h>
+#endif
 
 static const char imap_send_usage[] = "git imap-send < <mbox>";
 
@@ -91,8 +61,6 @@ static void imap_warn(const char *, ...);
 
 static char *next_arg(char **);
 
-static void free_generic_messages(struct message *);
-
 __attribute__((format (printf, 3, 4)))
 static int nfsnprintf(char *buf, int blen, const char *fmt, ...);
 
@@ -136,20 +104,6 @@ static struct imap_server_conf server = {
 	NULL,	/* auth_method */
 };
 
-struct imap_store_conf {
-	struct store_conf gen;
-	struct imap_server_conf *server;
-};
-
-#define NIL	(void *)0x1
-#define LIST	(void *)0x2
-
-struct imap_list {
-	struct imap_list *next, *child;
-	char *val;
-	int len;
-};
-
 struct imap_socket {
 	int fd[2];
 	SSL *ssl;
@@ -166,7 +120,6 @@ struct imap_cmd;
 
 struct imap {
 	int uidnext; /* from SELECT responses */
-	struct imap_list *ns_personal, *ns_other, *ns_shared; /* NAMESPACE info */
 	unsigned caps, rcaps; /* CAPABILITY results */
 	/* command queue */
 	int nexttag, num_in_progress, literal_pending;
@@ -175,11 +128,11 @@ struct imap {
 };
 
 struct imap_store {
-	struct store gen;
+	/* currently open mailbox */
+	const char *name; /* foreign! maybe preset? */
 	int uidvalidity;
 	struct imap *imap;
 	const char *prefix;
-	unsigned /*currentnc:1,*/ trashnc:1;
 };
 
 struct imap_cmd_cb {
@@ -226,14 +179,6 @@ static const char *cap_list[] = {
 static int get_cmd_result(struct imap_store *ctx, struct imap_cmd *tcmd);
 
 
-static const char *Flags[] = {
-	"Draft",
-	"Flagged",
-	"Answered",
-	"Seen",
-	"Deleted",
-};
-
 #ifndef NO_OPENSSL
 static void ssl_socket_perror(const char *func)
 {
@@ -266,12 +211,64 @@ static void socket_perror(const char *func, struct imap_socket *sock, int ret)
 	}
 }
 
+#ifdef NO_OPENSSL
 static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int verify)
 {
-#ifdef NO_OPENSSL
 	fprintf(stderr, "SSL requested but SSL support not compiled in\n");
 	return -1;
+}
+
 #else
+
+static int host_matches(const char *host, const char *pattern)
+{
+	if (pattern[0] == '*' && pattern[1] == '.') {
+		pattern += 2;
+		if (!(host = strchr(host, '.')))
+			return 0;
+		host++;
+	}
+
+	return *host && *pattern && !strcasecmp(host, pattern);
+}
+
+static int verify_hostname(X509 *cert, const char *hostname)
+{
+	int len;
+	X509_NAME *subj;
+	char cname[1000];
+	int i, found;
+	STACK_OF(GENERAL_NAME) *subj_alt_names;
+
+	/* try the DNS subjectAltNames */
+	found = 0;
+	if ((subj_alt_names = X509_get_ext_d2i(cert, NID_subject_alt_name, NULL, NULL))) {
+		int num_subj_alt_names = sk_GENERAL_NAME_num(subj_alt_names);
+		for (i = 0; !found && i < num_subj_alt_names; i++) {
+			GENERAL_NAME *subj_alt_name = sk_GENERAL_NAME_value(subj_alt_names, i);
+			if (subj_alt_name->type == GEN_DNS &&
+			    strlen((const char *)subj_alt_name->d.ia5->data) == (size_t)subj_alt_name->d.ia5->length &&
+			    host_matches(hostname, (const char *)(subj_alt_name->d.ia5->data)))
+				found = 1;
+		}
+		sk_GENERAL_NAME_pop_free(subj_alt_names, GENERAL_NAME_free);
+	}
+	if (found)
+		return 0;
+
+	/* try the common name */
+	if (!(subj = X509_get_subject_name(cert)))
+		return error("cannot get certificate subject");
+	if ((len = X509_NAME_get_text_by_NID(subj, NID_commonName, cname, sizeof(cname))) < 0)
+		return error("cannot get certificate common name");
+	if (strlen(cname) == (size_t)len && host_matches(hostname, cname))
+		return 0;
+	return error("certificate owner '%s' does not match hostname '%s'",
+		     cname, hostname);
+}
+
+static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int verify)
+{
 #if (OPENSSL_VERSION_NUMBER >= 0x10000000L)
 	const SSL_METHOD *meth;
 #else
@@ -279,6 +276,7 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
 #endif
 	SSL_CTX *ctx;
 	int ret;
+	X509 *cert;
 
 	SSL_library_init();
 	SSL_load_error_strings();
@@ -316,15 +314,35 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
 		return -1;
 	}
 
+#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
+	/*
+	 * SNI (RFC4366)
+	 * OpenSSL does not document this function, but the implementation
+	 * returns 1 on success, 0 on failure after calling SSLerr().
+	 */
+	ret = SSL_set_tlsext_host_name(sock->ssl, server.host);
+	if (ret != 1)
+		warning("SSL_set_tlsext_host_name(%s) failed.", server.host);
+#endif
+
 	ret = SSL_connect(sock->ssl);
 	if (ret <= 0) {
 		socket_perror("SSL_connect", sock, ret);
 		return -1;
 	}
 
+	if (verify) {
+		/* make sure the hostname matches that of the certificate */
+		cert = SSL_get_peer_certificate(sock->ssl);
+		if (!cert)
+			return error("unable to get peer certificate.");
+		if (verify_hostname(cert, server.host) < 0)
+			return -1;
+	}
+
 	return 0;
-#endif
 }
+#endif
 
 static int socket_read(struct imap_socket *sock, char *buf, int len)
 {
@@ -477,16 +495,6 @@ static char *next_arg(char **s)
 	return ret;
 }
 
-static void free_generic_messages(struct message *msgs)
-{
-	struct message *tmsg;
-
-	for (; msgs; msgs = tmsg) {
-		tmsg = msgs->next;
-		free(msgs);
-	}
-}
-
 static int nfsnprintf(char *buf, int blen, const char *fmt, ...)
 {
 	int ret;
@@ -614,35 +622,9 @@ static int imap_exec_m(struct imap_store *ctx, struct imap_cmd_cb *cb,
 	}
 }
 
-static int is_atom(struct imap_list *list)
+static int skip_imap_list_l(char **sp, int level)
 {
-	return list && list->val && list->val != NIL && list->val != LIST;
-}
-
-static int is_list(struct imap_list *list)
-{
-	return list && list->val == LIST;
-}
-
-static void free_list(struct imap_list *list)
-{
-	struct imap_list *tmp;
-
-	for (; list; list = tmp) {
-		tmp = list->next;
-		if (is_list(list))
-			free_list(list->child);
-		else if (is_atom(list))
-			free(list->val);
-		free(list);
-	}
-}
-
-static int parse_imap_list_l(struct imap *imap, char **sp, struct imap_list **curp, int level)
-{
-	struct imap_list *cur;
-	char *s = *sp, *p;
-	int n, bytes;
+	char *s = *sp;
 
 	for (;;) {
 		while (isspace((unsigned char)*s))
@@ -651,68 +633,23 @@ static int parse_imap_list_l(struct imap *imap, char **sp, struct imap_list **cu
 			s++;
 			break;
 		}
-		*curp = cur = xmalloc(sizeof(*cur));
-		curp = &cur->next;
-		cur->val = NULL; /* for clean bail */
 		if (*s == '(') {
 			/* sublist */
 			s++;
-			cur->val = LIST;
-			if (parse_imap_list_l(imap, &s, &cur->child, level + 1))
-				goto bail;
-		} else if (imap && *s == '{') {
-			/* literal */
-			bytes = cur->len = strtol(s + 1, &s, 10);
-			if (*s != '}')
-				goto bail;
-
-			s = cur->val = xmalloc(cur->len);
-
-			/* dump whats left over in the input buffer */
-			n = imap->buf.bytes - imap->buf.offset;
-
-			if (n > bytes)
-				/* the entire message fit in the buffer */
-				n = bytes;
-
-			memcpy(s, imap->buf.buf + imap->buf.offset, n);
-			s += n;
-			bytes -= n;
-
-			/* mark that we used part of the buffer */
-			imap->buf.offset += n;
-
-			/* now read the rest of the message */
-			while (bytes > 0) {
-				if ((n = socket_read(&imap->buf.sock, s, bytes)) <= 0)
-					goto bail;
-				s += n;
-				bytes -= n;
-			}
-
-			if (buffer_gets(&imap->buf, &s))
+			if (skip_imap_list_l(&s, level + 1))
 				goto bail;
 		} else if (*s == '"') {
 			/* quoted string */
 			s++;
-			p = s;
 			for (; *s != '"'; s++)
 				if (!*s)
 					goto bail;
-			cur->len = s - p;
 			s++;
-			cur->val = xmemdupz(p, cur->len);
 		} else {
 			/* atom */
-			p = s;
 			for (; *s && !isspace((unsigned char)*s); s++)
 				if (level && *s == ')')
 					break;
-			cur->len = s - p;
-			if (cur->len == 3 && !memcmp("NIL", p, 3))
-				cur->val = NIL;
-			else
-				cur->val = xmemdupz(p, cur->len);
 		}
 
 		if (!level)
@@ -721,27 +658,15 @@ static int parse_imap_list_l(struct imap *imap, char **sp, struct imap_list **cu
 			goto bail;
 	}
 	*sp = s;
-	*curp = NULL;
 	return 0;
 
 bail:
-	*curp = NULL;
 	return -1;
 }
 
-static struct imap_list *parse_imap_list(struct imap *imap, char **sp)
-{
-	struct imap_list *head;
-
-	if (!parse_imap_list_l(imap, sp, &head, 0))
-		return head;
-	free_list(head);
-	return NULL;
-}
-
-static struct imap_list *parse_list(char **sp)
+static void skip_list(char **sp)
 {
-	return parse_imap_list(NULL, sp);
+	skip_imap_list_l(sp, 0);
 }
 
 static void parse_capability(struct imap *imap, char *cmd)
@@ -773,7 +698,7 @@ static int parse_response_code(struct imap_store *ctx, struct imap_cmd_cb *cb,
 	*p++ = 0;
 	arg = next_arg(&s);
 	if (!strcmp("UIDVALIDITY", arg)) {
-		if (!(arg = next_arg(&s)) || !(ctx->gen.uidvalidity = atoi(arg))) {
+		if (!(arg = next_arg(&s)) || !(ctx->uidvalidity = atoi(arg))) {
 			fprintf(stderr, "IMAP error: malformed UIDVALIDITY status\n");
 			return RESP_BAD;
 		}
@@ -791,7 +716,7 @@ static int parse_response_code(struct imap_store *ctx, struct imap_cmd_cb *cb,
 		for (; isspace((unsigned char)*p); p++);
 		fprintf(stderr, "*** IMAP ALERT *** %s\n", p);
 	} else if (cb && cb->ctx && !strcmp("APPENDUID", arg)) {
-		if (!(arg = next_arg(&s)) || !(ctx->gen.uidvalidity = atoi(arg)) ||
+		if (!(arg = next_arg(&s)) || !(ctx->uidvalidity = atoi(arg)) ||
 		    !(arg = next_arg(&s)) || !(*(int *)cb->ctx = atoi(arg))) {
 			fprintf(stderr, "IMAP error: malformed APPENDUID status\n");
 			return RESP_BAD;
@@ -820,20 +745,28 @@ static int get_cmd_result(struct imap_store *ctx, struct imap_cmd *tcmd)
 			}
 
 			if (!strcmp("NAMESPACE", arg)) {
-				imap->ns_personal = parse_list(&cmd);
-				imap->ns_other = parse_list(&cmd);
-				imap->ns_shared = parse_list(&cmd);
+				/* rfc2342 NAMESPACE response. */
+				skip_list(&cmd); /* Personal mailboxes */
+				skip_list(&cmd); /* Others' mailboxes */
+				skip_list(&cmd); /* Shared mailboxes */
 			} else if (!strcmp("OK", arg) || !strcmp("BAD", arg) ||
 				   !strcmp("NO", arg) || !strcmp("BYE", arg)) {
 				if ((resp = parse_response_code(ctx, NULL, cmd)) != RESP_OK)
 					return resp;
-			} else if (!strcmp("CAPABILITY", arg))
+			} else if (!strcmp("CAPABILITY", arg)) {
 				parse_capability(imap, cmd);
-			else if ((arg1 = next_arg(&cmd))) {
-				if (!strcmp("EXISTS", arg1))
-					ctx->gen.count = atoi(arg);
-				else if (!strcmp("RECENT", arg1))
-					ctx->gen.recent = atoi(arg);
+			} else if ((arg1 = next_arg(&cmd))) {
+				; /*
+				   * Unhandled response-data with at least two words.
+				   * Ignore it.
+				   *
+				   * NEEDSWORK: Previously this case handled '<num> EXISTS'
+				   * and '<num> RECENT' but as a probably-unintended side
+				   * effect it ignores other unrecognized two-word
+				   * responses.  imap-send doesn't ever try to read
+				   * messages or mailboxes these days, so consider
+				   * eliminating this case.
+				   */
 			} else {
 				fprintf(stderr, "IMAP error: unable to parse untagged response\n");
 				return RESP_BAD;
@@ -935,16 +868,12 @@ static void imap_close_server(struct imap_store *ictx)
 		imap_exec(ictx, NULL, "LOGOUT");
 		socket_shutdown(&imap->buf.sock);
 	}
-	free_list(imap->ns_personal);
-	free_list(imap->ns_other);
-	free_list(imap->ns_shared);
 	free(imap);
 }
 
-static void imap_close_store(struct store *ctx)
+static void imap_close_store(struct imap_store *ctx)
 {
-	imap_close_server((struct imap_store *)ctx);
-	free_generic_messages(ctx->msgs);
+	imap_close_server(ctx);
 	free(ctx);
 }
 
@@ -1029,7 +958,7 @@ static int auth_cram_md5(struct imap_store *ctx, struct imap_cmd *cmd, const cha
 	return 0;
 }
 
-static struct store *imap_open_store(struct imap_server_conf *srvc)
+static struct imap_store *imap_open_store(struct imap_server_conf *srvc)
 {
 	struct imap_store *ctx;
 	struct imap *imap;
@@ -1239,173 +1168,113 @@ static struct store *imap_open_store(struct imap_server_conf *srvc)
 	} /* !preauth */
 
 	ctx->prefix = "";
-	ctx->trashnc = 1;
-	return (struct store *)ctx;
+	return ctx;
 
 bail:
-	imap_close_store(&ctx->gen);
+	imap_close_store(ctx);
 	return NULL;
 }
 
-static int imap_make_flags(int flags, char *buf)
-{
-	const char *s;
-	unsigned i, d;
-
-	for (i = d = 0; i < ARRAY_SIZE(Flags); i++)
-		if (flags & (1 << i)) {
-			buf[d++] = ' ';
-			buf[d++] = '\\';
-			for (s = Flags[i]; *s; s++)
-				buf[d++] = *s;
-		}
-	buf[0] = '(';
-	buf[d++] = ')';
-	return d;
-}
-
-static void lf_to_crlf(struct msg_data *msg)
+/*
+ * Insert CR characters as necessary in *msg to ensure that every LF
+ * character in *msg is preceded by a CR.
+ */
+static void lf_to_crlf(struct strbuf *msg)
 {
 	char *new;
-	int i, j, lfnum = 0;
-
-	if (msg->data[0] == '\n')
-		lfnum++;
-	for (i = 1; i < msg->len; i++) {
-		if (msg->data[i - 1] != '\r' && msg->data[i] == '\n')
-			lfnum++;
+	size_t i, j;
+	char lastc;
+
+	/* First pass: tally, in j, the size of the new string: */
+	for (i = j = 0, lastc = '\0'; i < msg->len; i++) {
+		if (msg->buf[i] == '\n' && lastc != '\r')
+			j++; /* a CR will need to be added here */
+		lastc = msg->buf[i];
+		j++;
 	}
 
-	new = xmalloc(msg->len + lfnum);
-	if (msg->data[0] == '\n') {
-		new[0] = '\r';
-		new[1] = '\n';
-		i = 1;
-		j = 2;
-	} else {
-		new[0] = msg->data[0];
-		i = 1;
-		j = 1;
-	}
-	for ( ; i < msg->len; i++) {
-		if (msg->data[i] != '\n') {
-			new[j++] = msg->data[i];
-			continue;
-		}
-		if (msg->data[i - 1] != '\r')
+	new = xmalloc(j + 1);
+
+	/*
+	 * Second pass: write the new string.  Note that this loop is
+	 * otherwise identical to the first pass.
+	 */
+	for (i = j = 0, lastc = '\0'; i < msg->len; i++) {
+		if (msg->buf[i] == '\n' && lastc != '\r')
 			new[j++] = '\r';
-		/* otherwise it already had CR before */
-		new[j++] = '\n';
+		lastc = new[j++] = msg->buf[i];
 	}
-	msg->len += lfnum;
-	free(msg->data);
-	msg->data = new;
+	strbuf_attach(msg, new, j, j + 1);
 }
 
-static int imap_store_msg(struct store *gctx, struct msg_data *data)
+/*
+ * Store msg to IMAP.  Also detach and free the data from msg->data,
+ * leaving msg->data empty.
+ */
+static int imap_store_msg(struct imap_store *ctx, struct strbuf *msg)
 {
-	struct imap_store *ctx = (struct imap_store *)gctx;
 	struct imap *imap = ctx->imap;
 	struct imap_cmd_cb cb;
 	const char *prefix, *box;
-	int ret, d;
-	char flagstr[128];
+	int ret;
 
-	lf_to_crlf(data);
+	lf_to_crlf(msg);
 	memset(&cb, 0, sizeof(cb));
 
-	cb.dlen = data->len;
-	cb.data = xmalloc(cb.dlen);
-	memcpy(cb.data, data->data, data->len);
+	cb.dlen = msg->len;
+	cb.data = strbuf_detach(msg, NULL);
 
-	d = 0;
-	if (data->flags) {
-		d = imap_make_flags(data->flags, flagstr);
-		flagstr[d++] = ' ';
-	}
-	flagstr[d] = 0;
-
-	box = gctx->name;
+	box = ctx->name;
 	prefix = !strcmp(box, "INBOX") ? "" : ctx->prefix;
 	cb.create = 0;
-	ret = imap_exec_m(ctx, &cb, "APPEND \"%s%s\" %s", prefix, box, flagstr);
+	ret = imap_exec_m(ctx, &cb, "APPEND \"%s%s\" ", prefix, box);
 	imap->caps = imap->rcaps;
 	if (ret != DRV_OK)
 		return ret;
-	gctx->count++;
 
 	return DRV_OK;
 }
 
-static void encode_html_chars(struct strbuf *p)
-{
-	int i;
-	for (i = 0; i < p->len; i++) {
-		if (p->buf[i] == '&')
-			strbuf_splice(p, i, 1, "&amp;", 5);
-		if (p->buf[i] == '<')
-			strbuf_splice(p, i, 1, "&lt;", 4);
-		if (p->buf[i] == '>')
-			strbuf_splice(p, i, 1, "&gt;", 4);
-		if (p->buf[i] == '"')
-			strbuf_splice(p, i, 1, "&quot;", 6);
-	}
-}
-static void wrap_in_html(struct msg_data *msg)
+static void wrap_in_html(struct strbuf *msg)
 {
 	struct strbuf buf = STRBUF_INIT;
-	struct strbuf **lines;
-	struct strbuf **p;
 	static char *content_type = "Content-Type: text/html;\n";
 	static char *pre_open = "<pre>\n";
 	static char *pre_close = "</pre>\n";
-	int added_header = 0;
-
-	strbuf_attach(&buf, msg->data, msg->len, msg->len);
-	lines = strbuf_split(&buf, '\n');
-	strbuf_release(&buf);
-	for (p = lines; *p; p++) {
-		if (! added_header) {
-			if ((*p)->len == 1 && *((*p)->buf) == '\n') {
-				strbuf_addstr(&buf, content_type);
-				strbuf_addbuf(&buf, *p);
-				strbuf_addstr(&buf, pre_open);
-				added_header = 1;
-				continue;
-			}
-		}
-		else
-			encode_html_chars(*p);
-		strbuf_addbuf(&buf, *p);
-	}
+	const char *body = strstr(msg->buf, "\n\n");
+
+	if (!body)
+		return; /* Headers but no body; no wrapping needed */
+
+	body += 2;
+
+	strbuf_add(&buf, msg->buf, body - msg->buf - 1);
+	strbuf_addstr(&buf, content_type);
+	strbuf_addch(&buf, '\n');
+	strbuf_addstr(&buf, pre_open);
+	strbuf_addstr_xml_quoted(&buf, body);
 	strbuf_addstr(&buf, pre_close);
-	strbuf_list_free(lines);
-	msg->len  = buf.len;
-	msg->data = strbuf_detach(&buf, NULL);
+
+	strbuf_release(msg);
+	*msg = buf;
 }
 
 #define CHUNKSIZE 0x1000
 
-static int read_message(FILE *f, struct msg_data *msg)
+static int read_message(FILE *f, struct strbuf *all_msgs)
 {
-	struct strbuf buf = STRBUF_INIT;
-
-	memset(msg, 0, sizeof(*msg));
-
 	do {
-		if (strbuf_fread(&buf, CHUNKSIZE, f) <= 0)
+		if (strbuf_fread(all_msgs, CHUNKSIZE, f) <= 0)
 			break;
 	} while (!feof(f));
 
-	msg->len  = buf.len;
-	msg->data = strbuf_detach(&buf, NULL);
-	return msg->len;
+	return ferror(f) ? -1 : 0;
 }
 
-static int count_messages(struct msg_data *msg)
+static int count_messages(struct strbuf *all_msgs)
 {
 	int count = 0;
-	char *p = msg->data;
+	char *p = all_msgs->buf;
 
 	while (1) {
 		if (!prefixcmp(p, "From ")) {
@@ -1426,34 +1295,39 @@ static int count_messages(struct msg_data *msg)
 	return count;
 }
 
-static int split_msg(struct msg_data *all_msgs, struct msg_data *msg, int *ofs)
+/*
+ * Copy the next message from all_msgs, starting at offset *ofs, to
+ * msg.  Update *ofs to the start of the following message.  Return
+ * true iff a message was successfully copied.
+ */
+static int split_msg(struct strbuf *all_msgs, struct strbuf *msg, int *ofs)
 {
 	char *p, *data;
+	size_t len;
 
-	memset(msg, 0, sizeof *msg);
 	if (*ofs >= all_msgs->len)
 		return 0;
 
-	data = &all_msgs->data[*ofs];
-	msg->len = all_msgs->len - *ofs;
+	data = &all_msgs->buf[*ofs];
+	len = all_msgs->len - *ofs;
 
-	if (msg->len < 5 || prefixcmp(data, "From "))
+	if (len < 5 || prefixcmp(data, "From "))
 		return 0;
 
 	p = strchr(data, '\n');
 	if (p) {
-		p = &p[1];
-		msg->len -= p-data;
-		*ofs += p-data;
+		p++;
+		len -= p - data;
+		*ofs += p - data;
 		data = p;
 	}
 
 	p = strstr(data, "\nFrom ");
 	if (p)
-		msg->len = &p[1] - data;
+		len = &p[1] - data;
 
-	msg->data = xmemdupz(data, msg->len);
-	*ofs += msg->len;
+	strbuf_add(msg, data, len);
+	*ofs += len;
 	return 1;
 }
 
@@ -1504,8 +1378,9 @@ static int git_imap_config(const char *key, const char *val, void *cb)
 
 int main(int argc, char **argv)
 {
-	struct msg_data all_msgs, msg;
-	struct store *ctx = NULL;
+	struct strbuf all_msgs = STRBUF_INIT;
+	struct strbuf msg = STRBUF_INIT;
+	struct imap_store *ctx = NULL;
 	int ofs = 0;
 	int r;
 	int total, n = 0;
@@ -1537,7 +1412,12 @@ int main(int argc, char **argv)
 	}
 
 	/* read the messages */
-	if (!read_message(stdin, &all_msgs)) {
+	if (read_message(stdin, &all_msgs)) {
+		fprintf(stderr, "error reading input\n");
+		return 1;
+	}
+
+	if (all_msgs.len == 0) {
 		fprintf(stderr, "nothing to send\n");
 		return 1;
 	}
@@ -1559,6 +1439,7 @@ int main(int argc, char **argv)
 	ctx->name = imap_folder;
 	while (1) {
 		unsigned percent = n * 100 / total;
+
 		fprintf(stderr, "%4u%% (%d/%d) done\r", percent, n, total);
 		if (!split_msg(&all_msgs, &msg, &ofs))
 			break;