diff -up dovecot-2.3.8/src/imap/imap-client-hibernate.c.CVE_2020_24386-prereq1 dovecot-2.3.8/src/imap/imap-client-hibernate.c

--- dovecot-2.3.8/src/imap/imap-client-hibernate.c.CVE_2020_24386-prereq1	2019-10-08 10:46:18.000000000 +0200

+++ dovecot-2.3.8/src/imap/imap-client-hibernate.c	2021-01-08 17:14:40.051174282 +0100

@@ -19,24 +19,26 @@

 #define IMAP_HIBERNATE_SEND_TIMEOUT_SECS 10

 #define IMAP_HIBERNATE_HANDSHAKE "VERSION\timap-hibernate\t1\t0\n"

-static int imap_hibernate_handshake(int fd, const char *path)

+static int

+imap_hibernate_handshake(int fd, const char *path, const char **error_r)

 {

 	char buf[1024];

 	ssize_t ret;

 	if (write_full(fd, IMAP_HIBERNATE_HANDSHAKE,

 		       strlen(IMAP_HIBERNATE_HANDSHAKE)) < 0) {

-		i_error("write(%s) failed: %m", path);

+		*error_r = t_strdup_printf("write(%s) failed: %m", path);

 		return -1;

 	} else if ((ret = read(fd, buf, sizeof(buf)-1)) < 0) {

-		i_error("read(%s) failed: %m", path);

+		*error_r = t_strdup_printf("read(%s) failed: %m", path);

 		return -1;

 	} else if (ret > 0 && buf[ret-1] == '\n') {

 		buf[ret-1] = '\0';

 		if (version_string_verify(buf, "imap-hibernate", 1))

 			return 0;

 	}

-	i_error("%s sent invalid VERSION handshake: %s", path, buf);

+	*error_r = t_strdup_printf("%s sent invalid VERSION handshake: %s",

+				   path, buf);

 	return -1;

 }

@@ -105,40 +107,42 @@ static void imap_hibernate_write_cmd(str

 static int

 imap_hibernate_process_send_cmd(int fd_socket, const char *path,

-				const string_t *cmd, int fd_client)

+				const string_t *cmd, int fd_client,

+				const char **error_r)

 {

 	ssize_t ret;

 	i_assert(fd_socket != -1);

 	i_assert(str_len(cmd) > 1);

-	if (imap_hibernate_handshake(fd_socket, path) < 0)

+	if (imap_hibernate_handshake(fd_socket, path, error_r) < 0)

 		return -1;

 	if ((ret = fd_send(fd_socket, fd_client, str_data(cmd), 1)) < 0) {

-		i_error("fd_send(%s) failed: %m", path);

+		*error_r = t_strdup_printf("fd_send(%s) failed: %m", path);

 		return -1;

 	}

 	if ((ret = write_full(fd_socket, str_data(cmd)+1, str_len(cmd)-1)) < 0) {

-		i_error("write(%s) failed: %m", path);

+		*error_r = t_strdup_printf("write(%s) failed: %m", path);

 		return -1;

 	}

 	return 0;

 }

-static int imap_hibernate_process_read(int fd, const char *path)

+static int

+imap_hibernate_process_read(int fd, const char *path, const char **error_r)

 {

 	char buf[1024];

 	ssize_t ret;

 	if ((ret = read(fd, buf, sizeof(buf)-1)) < 0) {

-		i_error("read(%s) failed: %m", path);

+		*error_r = t_strdup_printf("read(%s) failed: %m", path);

 		return -1;

 	} else if (ret == 0) {

-		i_error("%s disconnected", path);

+		*error_r = t_strdup_printf("%s disconnected", path);

 		return -1;

 	} else if (buf[0] != '+') {

 		buf[ret] = '\0';

-		i_error("%s returned failure: %s", path,

+		*error_r = t_strdup_printf("%s returned failure: %s", path,

 			ret > 0 && buf[0] == '-' ? buf+1 : buf);

 		return -1;

 	} else {

@@ -147,8 +151,8 @@ static int imap_hibernate_process_read(i

 }

 static int

-imap_hibernate_process_send(struct client *client,

-			    const buffer_t *state, int fd_notify, int *fd_r)

+imap_hibernate_process_send(struct client *client, const buffer_t *state,

+			    int fd_notify, int *fd_r, const char **error_r)

 {

 	string_t *cmd = t_str_new(512);

 	const char *path;

@@ -171,14 +175,14 @@ imap_hibernate_process_send(struct clien

 	imap_hibernate_write_cmd(client, cmd, state, fd_notify);

 	alarm(IMAP_HIBERNATE_SEND_TIMEOUT_SECS);

-	if (imap_hibernate_process_send_cmd(fd, path, cmd, client->fd_in) < 0 ||

-	    imap_hibernate_process_read(fd, path) < 0)

+	if (imap_hibernate_process_send_cmd(fd, path, cmd, client->fd_in, error_r) < 0 ||

+	    imap_hibernate_process_read(fd, path, error_r) < 0)

 		ret = -1;

 	else if (fd_notify != -1) {

 		if ((ret = fd_send(fd, fd_notify, "\n", 1)) < 0)

-			i_error("fd_send(%s) failed: %m", path);

+			*error_r = t_strdup_printf("fd_send(%s) failed: %m", path);

 		else

-			ret = imap_hibernate_process_read(fd, path);

+			ret = imap_hibernate_process_read(fd, path, error_r);

 	}

 	alarm(0);

 	if (ret < 0) {

@@ -229,8 +233,12 @@ bool imap_client_hibernate(struct client

 		}

 	}

 	if (ret > 0) {

-		if (imap_hibernate_process_send(client, state, fd_notify, &fd_hibernate) < 0)

+		if (imap_hibernate_process_send(client, state, fd_notify,

+						&fd_hibernate, &error) < 0) {

+			e_error(client->event,

+				"Couldn't hibernate imap client: %s", error);

 			ret = -1;

+		}

 	}

 	i_close_fd(&fd_notify);

 	if (ret > 0) {