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-rw-r--r--src/clamsmtpd.c1215
1 files changed, 1215 insertions, 0 deletions
diff --git a/src/clamsmtpd.c b/src/clamsmtpd.c
new file mode 100644
index 0000000..71e5a3f
--- /dev/null
+++ b/src/clamsmtpd.c
@@ -0,0 +1,1215 @@
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <paths.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <signal.h>
+#include <errno.h>
+
+#include "usuals.h"
+#include "compat.h"
+#include "sock_any.h"
+#include "clamsmtpd.h"
+#include "util.h"
+
+/* -----------------------------------------------------------------------
+ * Structures
+ */
+
+typedef struct clamsmtp_thread
+{
+ pthread_t tid; /* Written to by the main thread */
+ int fd; /* The file descriptor or -1 */
+}
+clamsmtp_thread_t;
+
+#define LINE_TOO_LONG(ctx) ((ctx)->linelen >= (LINE_LENGTH - 2))
+#define RETURN(x) { ret = x; goto cleanup; }
+
+/* -----------------------------------------------------------------------
+ * Strings
+ */
+
+#define KL(s) ((sizeof(s) - 1) / sizeof(char))
+
+#define SMTP_TOOLONG "500 Line too long\r\n"
+#define SMTP_STARTBUSY "554 Server Busy\r\n"
+#define SMTP_STARTFAILED "554 Local Error\r\n"
+#define SMTP_DATAVIRUS "550 Virus Detected; Content Rejected\r\n"
+#define SMTP_DATAINTERMED "354 Start mail input; end with <CRLF>.<CRLF>\r\n"
+#define SMTP_FAILED "451 Local Error\r\n"
+
+#define SMTP_DATA "DATA\r\n"
+#define SMTP_DELIMS "\r\n\t :"
+
+#define FROM_CMD "MAIL FROM"
+#define TO_CMD "RCPT TO"
+#define DATA_CMD "DATA"
+#define RSET_CMD "RSET"
+
+#define DATA_END_SIG "\r\n.\r\n"
+
+#define DATA_RSP "354"
+
+#define CLAM_OK "OK"
+#define CLAM_ERROR "ERROR"
+#define CLAM_FOUND "FOUND"
+
+#define CONNECT_RSP "PONG"
+#define CLAM_SCAN "SCAN "
+
+#define CLAM_CONNECT "SESSION\nPING\n"
+#define CLAM_DISCONNECT "END\n"
+
+/* -----------------------------------------------------------------------
+ * Default Settings
+ */
+
+#define DEFAULT_SOCKET "0.0.0.0:10025"
+#define DEFAULT_PORT 10025
+#define DEFAULT_CLAMAV "/var/run/clamav/clamd"
+#define DEFAULT_MAXTHREADS 64
+#define DEFAULT_TIMEOUT 180
+#define DEFAULT_HEADER "X-AV-Checked: ClamAV using ClamSMTP\r\n"
+
+
+/* -----------------------------------------------------------------------
+ * Globals
+ */
+
+int g_daemonized = 0; /* Currently running as a daemon */
+int g_debuglevel = LOG_ERR; /* what gets logged to console */
+int g_maxthreads = DEFAULT_MAXTHREADS; /* The maximum number of threads */
+struct timeval g_timeout = { DEFAULT_TIMEOUT, 0 };
+
+struct sockaddr_any g_outaddr; /* The outgoing address */
+const char* g_outname = NULL;
+struct sockaddr_any g_clamaddr; /* Address for connecting to clamd */
+const char* g_clamname = DEFAULT_CLAMAV;
+
+const char* g_header = DEFAULT_HEADER; /* The header to add to email */
+const char* g_directory = _PATH_TMP; /* The directory for temp files */
+unsigned int g_unique_id = 0x00001000; /* For connection ids */
+
+/* For main loop and signal handlers */
+int g_quit = 0;
+
+/* The main mutex and condition variables */
+pthread_mutex_t g_mutex;
+pthread_mutexattr_t g_mutexattr;
+
+
+/* -----------------------------------------------------------------------
+ * Forward Declarations
+ */
+
+static usage();
+static void on_quit(int signal);
+static void write_pid(const char* pid);
+static void connection_loop(int sock);
+static void* thread_main(void* arg);
+static int smtp_passthru(clamsmtp_context_t* ctx);
+static int connect_clam(clamsmtp_context_t* ctx);
+static int disconnect_clam(clamsmtp_context_t* ctx);
+static void add_to_logline(char* logline, char* prefix, char* line);
+static int avcheck_data(clamsmtp_context_t* ctx, char* logline);
+static int complete_data_transfer(clamsmtp_context_t* ctx, const char* tempname);
+static int transfer_to_file(clamsmtp_context_t* ctx, char* tempname);
+static int transfer_from_file(clamsmtp_context_t* ctx, const char* filename);
+static int clam_scan_file(clamsmtp_context_t* ctx, const char* tempname, char* logline);
+static int read_server_response(clamsmtp_context_t* ctx);
+static void read_junk(clamsmtp_context_t* ctx, int fd);
+static int read_line(clamsmtp_context_t* ctx, int* fd, int trim);
+static int write_data(clamsmtp_context_t* ctx, int* fd, unsigned char* buf);
+static int write_data_raw(clamsmtp_context_t* ctx, int* fd, unsigned char* buf, int len);
+
+
+int main(int argc, char* argv[])
+{
+ const char* listensock = DEFAULT_SOCKET;
+ clamsmtp_thread_t* threads = NULL;
+ struct sockaddr_any addr;
+ char* pidfile = NULL;
+ int daemonize = 1;
+ int sock;
+ int true = 1;
+ int ch = 0;
+ char* t;
+
+ /* Parse the arguments nicely */
+ while((ch = getopt(argc, argv, "c:d:D:h:l:m:p:t:")) != -1)
+ {
+ switch(ch)
+ {
+ /* Change the CLAM socket */
+ case 'c':
+ g_clamname = optarg;
+ break;
+
+ /* Don't daemonize */
+ case 'd':
+ daemonize = 0;
+ g_debuglevel = strtol(optarg, &t, 10);
+ if(*t || g_debuglevel > 4)
+ errx(1, "invalid debug log level");
+ g_debuglevel += LOG_ERR;
+ break;
+
+ /* The directory for the files */
+ case 'D':
+ g_directory = optarg;
+ break;
+
+ /* The header to add */
+ case 'h':
+ if(strlen(optarg) == 0)
+ g_header = NULL;
+ else
+ g_header = optarg;
+ break;
+
+ /* Change our listening port */
+ case 'l':
+ listensock = optarg;
+ break;
+
+ /* The maximum number of threads */
+ case 'm':
+ g_maxthreads = strtol(optarg, &t, 10);
+ if(*t || g_maxthreads <= 1 || g_maxthreads >= 1024)
+ errx(1, "invalid max threads (must be between 1 and 1024");
+ break;
+
+ /* Write out a pid file */
+ case 'p':
+ pidfile = optarg;
+ break;
+
+ /* The timeout */
+ case 't':
+ g_timeout.tv_sec = strtol(optarg, &t, 10);
+ if(*t || g_timeout.tv_sec <= 0)
+ errx(1, "invalid timeout: %s", optarg);
+ break;
+
+ /* Usage information */
+ case '?':
+ default:
+ usage();
+ break;
+ }
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if(argc != 1)
+ usage();
+
+ g_outname = argv[0];
+
+ messagex(NULL, LOG_DEBUG, "starting up...");
+
+ /* Parse all the addresses */
+ if(sock_any_pton(listensock, &addr, DEFAULT_PORT) == -1)
+ errx(1, "invalid listen socket name or ip: %s", listensock);
+ if(sock_any_pton(g_outname, &g_outaddr, 25) == -1)
+ errx(1, "invalid connect socket name or ip: %s", g_outname);
+ if(sock_any_pton(g_clamname, &g_clamaddr, 0) == -1)
+ errx(1, "invalid clam socket name: %s", g_clamname);
+
+ /* Create the socket */
+ sock = socket(SANY_TYPE(addr), SOCK_STREAM, 0);
+ if(sock < 0)
+ err(1, "couldn't open socket");
+
+ setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&true, sizeof(true));
+
+ /* Unlink the socket file if it exists */
+ if(SANY_TYPE(addr) == AF_UNIX)
+ unlink(listensock);
+
+ if(bind(sock, &SANY_ADDR(addr), SANY_LEN(addr)) != 0)
+ err(1, "couldn't bind to address: %s", listensock);
+
+ /* Let 5 connections queue up */
+ if(listen(sock, 5) != 0)
+ err(1, "couldn't listen on socket");
+
+ messagex(NULL, LOG_DEBUG, "created socket: %s", listensock);
+
+ if(daemonize)
+ {
+ /* Fork a daemon nicely here */
+ if(daemon(0, 0) == -1)
+ {
+ message(NULL, LOG_ERR, "couldn't run as daemon");
+ exit(1);
+ }
+
+ messagex(NULL, LOG_DEBUG, "running as a daemon");
+ g_daemonized = 1;
+
+ /* Open the system log */
+ openlog("clamsmtp", 0, LOG_MAIL);
+ }
+
+ if(pidfile)
+ write_pid(pidfile);
+
+ /* Handle some signals */
+ signal(SIGPIPE, SIG_IGN);
+ signal(SIGHUP, SIG_IGN);
+ signal(SIGINT, on_quit);
+ signal(SIGTERM, on_quit);
+
+ siginterrupt(SIGINT, 1);
+ siginterrupt(SIGTERM, 1);
+
+ messagex(NULL, LOG_DEBUG, "accepting connections");
+
+ connection_loop(sock);
+
+ messagex(NULL, LOG_DEBUG, "stopped");
+
+ return 0;
+}
+
+static void connection_loop(int sock)
+{
+ clamsmtp_thread_t* threads = NULL;
+ struct sockaddr_any addr;
+ int fd, i, x, r;
+
+ /* Create the thread buffers */
+ threads = (clamsmtp_thread_t*)calloc(g_maxthreads, sizeof(clamsmtp_thread_t));
+ if(!threads)
+ errx(1, "out of memory");
+
+ /* Create the main mutex and condition variable */
+ if(pthread_mutexattr_init(&g_mutexattr) != 0 ||
+ pthread_mutexattr_settype(&g_mutexattr, MUTEX_TYPE) ||
+ pthread_mutex_init(&g_mutex, &g_mutexattr) != 0)
+ errx(1, "threading problem. can't create mutex or condition var");
+
+ /* Now loop and accept the connections */
+ while(!g_quit)
+ {
+ fd = accept(sock, NULL, NULL);
+ if(fd == -1)
+ {
+ switch(errno)
+ {
+ case EINTR:
+ case EAGAIN:
+ break;
+
+ case ECONNABORTED:
+ message(NULL, LOG_ERR, "couldn't accept a connection");
+ break;
+
+ default:
+ message(NULL, LOG_ERR, "couldn't accept a connection");
+ g_quit = 1;
+ break;
+ };
+
+ if(g_quit)
+ break;
+
+ continue;
+ }
+
+ /* Look for thread and also clean up others */
+ for(i = 0; i < g_maxthreads; i++)
+ {
+ /* Find a thread to run or clean up old threads */
+ if(threads[i].tid != 0)
+ {
+ plock();
+ x = threads[i].fd;
+ punlock();
+
+ if(x == -1)
+ {
+ messagex(NULL, LOG_DEBUG, "cleaning up completed thread");
+ pthread_join(threads[i].tid, NULL);
+ threads[i].tid = 0;
+ }
+ }
+
+ /* Start a new thread if neccessary */
+ if(fd != -1 && threads[i].tid == 0)
+ {
+ threads[i].fd = fd;
+ r = pthread_create(&(threads[i].tid), NULL, thread_main,
+ (void*)(threads + i));
+ if(r != 0)
+ {
+ errno = r;
+ message(NULL, LOG_ERR, "couldn't create thread");
+ g_quit = 1;
+ break;
+ }
+
+ messagex(NULL, LOG_DEBUG, "created thread for connection");
+ fd = -1;
+ break;
+ }
+ }
+
+ /* Check to make sure we have a thread */
+ if(fd != -1)
+ {
+ messagex(NULL, LOG_ERR, "too many connections open (max %d)", g_maxthreads);
+
+ /* TODO: Respond with a too many connections message */
+ write_data(NULL, &fd, SMTP_STARTBUSY);
+ shutdown(fd, SHUT_RDWR);
+ }
+ }
+
+ messagex(NULL, LOG_INFO, "waiting for threads to quit");
+
+ /* Quit all threads here */
+ for(i = 0; i < g_maxthreads; i++)
+ {
+ /* Clean up quit threads */
+ if(threads[i].tid != 0)
+ {
+ if(threads[i].fd != -1)
+ shutdown(threads[i].fd, SHUT_RDWR);
+
+ pthread_join(threads[i].tid, NULL);
+ }
+ }
+
+ /* Close the mutex */
+ pthread_mutex_destroy(&g_mutex);
+ pthread_mutexattr_destroy(&g_mutexattr);
+}
+
+static void on_quit(int signal)
+{
+ g_quit = 1;
+
+ /* fprintf(stderr, "clamsmtpd: got signal to quit\n"); */
+}
+
+static int usage()
+{
+ fprintf(stderr, "clamsmtp [-c clamaddr] [-d debuglevel] [-D tmpdir] [-h header]"
+ "[-l listenaddr] [-m maxconn] [-p pidfile] [-t timeout] serveraddr\n");
+ return 2;
+}
+
+static void write_pid(const char* pidfile)
+{
+ FILE* f = fopen(pidfile, "w");
+ if(f == NULL)
+ {
+ message(NULL, LOG_ERR, "couldn't open pid file: %s", pidfile);
+ }
+ else
+ {
+ fprintf(f, "%d\n", (int)getpid());
+
+ if(ferror(f))
+ message(NULL, LOG_ERR, "couldn't write to pid file: %s", pidfile);
+
+ fclose(f);
+ }
+}
+
+static void* thread_main(void* arg)
+{
+ clamsmtp_thread_t* thread = (clamsmtp_thread_t*)arg;
+ char peername[MAXPATHLEN];
+ struct sockaddr_any addr;
+ clamsmtp_context_t ctx;
+ int r;
+
+ ASSERT(thread);
+
+ siginterrupt(SIGINT, 1);
+ siginterrupt(SIGTERM, 1);
+
+ memset(&ctx, 0, sizeof(ctx));
+
+ plock();
+ ctx.client = thread->fd;
+ punlock();
+
+ ctx.server = -1;
+ ctx.clam = -1;
+
+ ASSERT(ctx.client != -1);
+
+ /* Assign a unique id to the connection */
+ ctx.id = g_unique_id++;
+
+ /* Get the peer name */
+ if(getpeername(ctx.client, &SANY_ADDR(addr), &SANY_LEN(addr)) == -1 ||
+ sock_any_ntop(&addr, peername, MAXPATHLEN) == -1)
+ messagex(&ctx, LOG_WARNING, "couldn't get peer address");
+ else
+ messagex(&ctx, LOG_INFO, "accepted connection from: %s", peername);
+
+ /* call the processor */
+ r = smtp_passthru(&ctx);
+
+ /* Close the incoming connection if neccessary */
+ if(ctx.client != -1)
+ shutdown(ctx.client, SHUT_RDWR);
+
+ messagex(&ctx, LOG_INFO, "closed client connection");
+
+ /* mark this as done */
+ plock();
+ thread->fd = -1;
+ punlock();
+
+ return (void*)(r == 0 ? 0 : 1);
+}
+
+static int smtp_passthru(clamsmtp_context_t* ctx)
+{
+ char logline[LINE_LENGTH];
+ int processing = 0;
+ int r, ret = 0;
+ fd_set mask;
+
+ ASSERT(ctx->server == -1);
+
+ if((ctx->server = socket(SANY_TYPE(g_outaddr), SOCK_STREAM, 0)) < 0 ||
+ connect(ctx->server, &SANY_ADDR(g_outaddr), SANY_LEN(g_outaddr)) < 0)
+ {
+ message(ctx, LOG_ERR, "couldn't connect to %s", g_outname);
+ RETURN(-1);
+ }
+
+ messagex(ctx, LOG_DEBUG, "connected to server: %s", g_outname);
+
+ if(connect_clam(ctx) == -1)
+ RETURN(-1);
+
+ /* This changes the error code sent to the client when an
+ * error occurs. See cleanup below */
+ processing = 1;
+ logline[0] = 0;
+
+ for(;;)
+ {
+ FD_ZERO(&mask);
+
+ FD_SET(ctx->client, &mask);
+ FD_SET(ctx->server, &mask);
+
+ switch(select(FD_SETSIZE, &mask, NULL, NULL, &g_timeout))
+ {
+ case 0:
+ message(ctx, LOG_ERR, "network operation timed out");
+ RETURN(-1);
+ case -1:
+ message(ctx, LOG_ERR, "couldn't select on sockets");
+ RETURN(-1);
+ };
+
+ /* Client has data available, read a line and process */
+ if(FD_ISSET(ctx->client, &mask))
+ {
+ if(read_line(ctx, &(ctx->client), 0) == -1)
+ RETURN(-1);
+
+ /* Client disconnected, we're done */
+ if(ctx->linelen == 0)
+ RETURN(0);
+
+ /* We don't let clients send really long lines */
+ if(LINE_TOO_LONG(ctx))
+ {
+ if(write_data(ctx, &(ctx->server), SMTP_TOOLONG) == -1)
+ RETURN(-1);
+ }
+
+ else
+ {
+ if(is_first_word(ctx->line, DATA_CMD, KL(DATA_CMD)))
+ {
+ /* Send back the intermediate response to the client */
+ if(write_data(ctx, &(ctx->client), SMTP_DATAINTERMED) == -1)
+ RETURN(-1);
+
+ /*
+ * Now go into avcheck mode. This also handles the eventual
+ * sending of the data to the server, making the av check
+ * transparent
+ */
+ if(avcheck_data(ctx, logline) == -1)
+ RETURN(-1);
+
+ /* Print the log out for this email */
+ messagex(ctx, LOG_INFO, "%s", logline);
+
+ /* Reset log line */
+ logline[0] = 0;
+ }
+
+ /* All other commands just get passed through to server */
+ else
+ {
+
+ /* Append recipients to log line */
+ if((r = check_first_word(ctx->line, FROM_CMD, KL(FROM_CMD), SMTP_DELIMS)) > 0)
+ add_to_logline(logline, "from=", ctx->line + r);
+
+ /* Append sender to log line */
+ else if((r = check_first_word(ctx->line, TO_CMD, KL(TO_CMD), SMTP_DELIMS)) > 0)
+ add_to_logline(logline, "to=", ctx->line + r);
+
+ /* Reset log line */
+ else if(is_first_word(ctx->line, RSET_CMD, KL(RSET_CMD)))
+ logline[0] = 0;
+
+ if(write_data(ctx, &(ctx->server), ctx->line) == -1)
+ RETURN(-1);
+ }
+ }
+
+ continue;
+ }
+
+ /* Server has data available, read a line and forward */
+ if(FD_ISSET(ctx->server, &mask))
+ {
+ if(read_line(ctx, &(ctx->server), 0) == -1)
+ RETURN(-1);
+
+ if(ctx->linelen == 0)
+ RETURN(0);
+
+ if(LINE_TOO_LONG(ctx))
+ messagex(ctx, LOG_WARNING, "SMTP response line too long. discarded extra");
+
+ if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+ RETURN(-1);
+
+ continue;
+ }
+ }
+
+cleanup:
+
+ disconnect_clam(ctx);
+
+ if(ret == -1 && ctx->client != -1)
+ {
+ write_data(ctx, &(ctx->client),
+ processing ? SMTP_FAILED : SMTP_STARTFAILED);
+ }
+
+ if(ctx->server != -1)
+ {
+ shutdown(ctx->server, SHUT_RDWR);
+ messagex(ctx, LOG_DEBUG, "closed server connection");
+ }
+
+ return ret;
+}
+
+static void add_to_logline(char* logline, char* prefix, char* line)
+{
+ int l = strlen(logline);
+ char* t = logline;
+
+ /* Simple optimization */
+ logline += l;
+ l = LINE_LENGTH - l;
+
+ ASSERT(l >= 0);
+
+ if(t[0] != 0)
+ strlcat(logline, ", ", l);
+
+ strlcat(logline, prefix, l);
+
+ /* Skip initial white space */
+ while(*line && isspace(*line))
+ *line++;
+
+ strlcat(logline, line, l);
+ t = logline + strlen(logline);
+
+ /* Skip later white space */
+ while(t > logline && isspace(*(t - 1)))
+ *(--t) = 0;
+}
+
+static int connect_clam(clamsmtp_context_t* ctx)
+{
+ int r, len = -1;
+ int ret = 0;
+
+ ASSERT(ctx);
+ ASSERT(ctx->clam == -1);
+
+ if((ctx->clam = socket(SANY_TYPE(g_clamaddr), SOCK_STREAM, 0)) < 0 ||
+ connect(ctx->clam, &SANY_ADDR(g_clamaddr), SANY_LEN(g_clamaddr)) < 0)
+ {
+ message(ctx, LOG_ERR, "couldn't connect to clamd at %s", g_clamname);
+ RETURN(-1);
+ }
+
+ read_junk(ctx, ctx->clam);
+
+ /* Send a session and a check header to ClamAV */
+
+ if(write_data(ctx, &(ctx->clam), "SESSION\n") == -1)
+ RETURN(-1);
+
+ read_junk(ctx, ctx->clam);
+/*
+ if(write_data(ctx, &(ctx->clam), "PING\n") == -1 ||
+ read_line(ctx, &(ctx->clam), 1) == -1)
+ RETURN(-1);
+
+ if(strcmp(ctx->line, CONNECT_RESPONSE) != 0)
+ {
+ message(ctx, LOG_ERR, "clamd sent an unexpected response: %s", ctx->line);
+ RETURN(-1);
+ }
+*/
+ messagex(ctx, LOG_DEBUG, "connected to clamd: %s", g_clamname);
+
+cleanup:
+
+ if(ret < 0)
+ {
+ if(ctx->clam != -1)
+ {
+ shutdown(ctx->clam, SHUT_RDWR);
+ ctx->clam == -1;
+ }
+ }
+
+ return ret;
+}
+
+static int disconnect_clam(clamsmtp_context_t* ctx)
+{
+ if(ctx->clam == -1)
+ return 0;
+
+ if(write_data(ctx, &(ctx->clam), CLAM_DISCONNECT) != -1)
+ read_junk(ctx, ctx->clam);
+
+ messagex(ctx, LOG_DEBUG, "disconnected from clamd");
+ shutdown(ctx->clam, SHUT_RDWR);
+ ctx->clam = -1;
+ return 0;
+}
+
+static int clam_scan_file(clamsmtp_context_t* ctx, const char* tempname, char* logline)
+{
+ int len;
+
+ ASSERT(LINE_LENGTH < MAXPATHLEN + 32);
+
+ strcpy(ctx->line, CLAM_SCAN);
+ strcat(ctx->line, tempname);
+ strcat(ctx->line, "\n");
+
+ if(write_data(ctx, &(ctx->clam), ctx->line) == -1)
+ return -1;
+
+ len = read_line(ctx, &(ctx->clam), 1);
+ if(len == 0)
+ {
+ messagex(ctx, LOG_ERR, "clamd disconnected unexpectedly");
+ return -1;
+ }
+
+ if(is_last_word(ctx->line, CLAM_OK, KL(CLAM_OK)))
+ {
+ add_to_logline(logline, "status=", "CLEAN");
+ messagex(ctx, LOG_DEBUG, "no virus");
+ return 0;
+ }
+
+ if(is_last_word(ctx->line, CLAM_FOUND, KL(CLAM_FOUND)))
+ {
+ len = strlen(tempname);
+
+ if(ctx->linelen > len)
+ add_to_logline(logline, "status=VIRUS:", ctx->line + len + 1);
+ else
+ add_to_logline(logline, "status=", "VIRUS");
+
+ messagex(ctx, LOG_DEBUG, "found virus");
+ return 1;
+ }
+
+ if(is_last_word(ctx->line, CLAM_ERROR, KL(CLAM_ERROR)))
+ {
+ messagex(ctx, LOG_ERR, "clamav error: %s", ctx->line);
+ return -1;
+ }
+
+ messagex(ctx, LOG_ERR, "unexepected response from clamd: %s", ctx->line);
+ return -1;
+}
+
+static int avcheck_data(clamsmtp_context_t* ctx, char* logline)
+{
+ /*
+ * Note that most failures are non fatal in this function.
+ * We only return -1 for data connection errors and the like,
+ * For most others we actually send a response back to the
+ * client letting them know what happened and let the SMTP
+ * connection continue.
+ */
+
+ char buf[MAXPATHLEN];
+ int havefile = 0;
+ int r, ret = 0;
+
+ strlcpy(buf, g_directory, MAXPATHLEN);
+ strlcat(buf, "/clamsmtp.XXXXXX", MAXPATHLEN);
+
+ /* transfer_to_file deletes the temp file on failure */
+ if((r = transfer_to_file(ctx, buf)) > 0)
+ {
+ havefile = 1;
+ r = clam_scan_file(ctx, buf, logline);
+ }
+
+ switch(r)
+ {
+
+ /*
+ * There was an error tell the client. We haven't notified
+ * the server about any of this yet
+ */
+ case -1:
+ if(write_data(ctx, &(ctx->client), SMTP_FAILED))
+ RETURN(-1);
+ break;
+
+ /*
+ * No virus was found. Now we initiate a connection to the server
+ * and transfer the file to it.
+ */
+ case 0:
+ if(complete_data_transfer(ctx, buf) == -1)
+ RETURN(-1);
+ break;
+
+ /*
+ * A virus was found, just send back a simple message to the client.
+ * The server doesn't know data was ever sent, and the client can
+ * choose to reset the connection to reuse it if it wants.
+ */
+ case 1:
+ if(write_data(ctx, &(ctx->client), SMTP_DATAVIRUS) == -1)
+ RETURN(-1);
+ break;
+
+ default:
+ ASSERT(0 && "Invalid clam_scan_file return value");
+ break;
+ };
+
+cleanup:
+ if(havefile)
+ {
+ messagex(ctx, LOG_DEBUG, "deleting temporary file: %s", buf);
+ unlink(buf);
+ }
+
+ return ret;
+}
+
+static int complete_data_transfer(clamsmtp_context_t* ctx, const char* tempname)
+{
+ ASSERT(ctx);
+ ASSERT(tempname);
+
+ /* Ask the server for permission to send data */
+ if(write_data(ctx, &(ctx->server), SMTP_DATA) == -1)
+ return -1;
+
+ if(read_server_response(ctx) == -1)
+ return -1;
+
+ /* If server returns an error then tell the client */
+ if(!is_first_word(ctx->line, DATA_RSP, KL(DATA_RSP)))
+ {
+ if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+ return -1;
+
+ messagex(ctx, LOG_DEBUG, "server refused data transfer");
+
+ return 0;
+ }
+
+ /* Now pull up the file and send it to the server */
+ if(transfer_from_file(ctx, tempname) == -1)
+ {
+ /* Tell the client it went wrong */
+ write_data(ctx, &(ctx->client), SMTP_FAILED);
+ return -1;
+ }
+
+ /* Okay read the response from the server and echo it to the client */
+ if(read_server_response(ctx) == -1)
+ return -1;
+
+ if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+ return -1;
+
+ return 0;
+}
+
+static int transfer_to_file(clamsmtp_context_t* ctx, char* tempname)
+{
+ /* If there aren't any lines in the message and just an
+ end signature then start at the dot. */
+ const char* topsig = strchr(DATA_END_SIG, '.');
+ const char* cursig = topsig;
+ FILE* tfile = NULL;
+ int tfd = -1;
+ int ret = 0;
+ char ch;
+ int count = 0;
+
+ ASSERT(topsig != NULL);
+
+ if((tfd = mkstemp(tempname)) == -1 ||
+ (tfile = fdopen(tfd, "w")) == NULL)
+ {
+ message(ctx, LOG_ERR, "couldn't open temp file");
+ RETURN(-1);
+ }
+
+ messagex(ctx, LOG_DEBUG, "created temporary file: %s", tempname);
+
+ for(;;)
+ {
+ switch(read(ctx->client, &ch, 1))
+ {
+ case 0:
+ messagex(ctx, LOG_ERR, "unexpected end of data from client");
+ RETURN(-1);
+
+ case -1:
+ message(ctx, LOG_ERR, "error reading from client");
+ RETURN(-1);
+ };
+
+ if((char)ch != *cursig)
+ {
+ /* Write out the part of the sig we kept back */
+ if(cursig != topsig)
+ {
+ /* We check errors on this later */
+ fwrite(topsig, 1, cursig - topsig, tfile);
+ count += (cursig - topsig);
+ }
+
+ /* We've seen at least one char not in the sig */
+ cursig = topsig = DATA_END_SIG;
+ }
+
+ /* The sig may have been reset above so check again */
+ if((char)ch == *cursig)
+ {
+ cursig++;
+
+ if(!*cursig)
+ {
+ /* We found end of data */
+ break;
+ }
+ }
+
+ else
+ {
+ fputc(ch, tfile);
+ count++;
+ }
+ }
+
+ if(ferror(tfile))
+ {
+ message(ctx, LOG_ERR, "error writing to temp file: %s", tempname);
+ RETURN(-1);
+ }
+
+ ret = count;
+ messagex(ctx, LOG_DEBUG, "wrote %d bytes to temp file", count);
+
+cleanup:
+
+ if(tfile)
+ fclose(tfile);
+
+ if(tfd != -1)
+ {
+ /* Only close this if not opened as a stream */
+ if(tfile == NULL)
+ close(tfd);
+
+ if(ret == -1)
+ {
+ messagex(ctx, LOG_DEBUG, "discarding temporary file");
+ unlink(tempname);
+ }
+ }
+
+ return ret;
+}
+
+static int transfer_from_file(clamsmtp_context_t* ctx, const char* filename)
+{
+ FILE* file = NULL;
+ const char* t;
+ const char* e;
+ int header = 0;
+ int ret = 0;
+ int len, r;
+
+ file = fopen(filename, "r");
+ if(file == NULL)
+ {
+ message(ctx, LOG_ERR, "couldn't open temporary file: %s", filename);
+ RETURN(-1);
+ }
+
+ messagex(ctx, LOG_DEBUG, "opened temporary file: %s", filename);
+
+ while(fgets(ctx->line, LINE_LENGTH, file) != NULL)
+ {
+ if(g_header && !header)
+ {
+ /*
+ * The first blank line we see means the headers are done.
+ * At this point we add in our virus checked header.
+ */
+ if(is_blank_line(ctx->line))
+ {
+ if(write_data_raw(ctx, &(ctx->server), g_header, strlen(g_header)) == -1)
+ RETURN(-1);
+ }
+
+ header = 1;
+ }
+
+ if(write_data_raw(ctx, &(ctx->server), ctx->line, strlen(ctx->line)) == -1)
+ RETURN(-1);
+ }
+
+ if(ferror(file))
+ {
+ message(ctx, LOG_ERR, "error reading temporary file: %s", filename);
+ RETURN(-1);
+ }
+
+ if(write_data(ctx, &(ctx->server), DATA_END_SIG) == -1)
+ RETURN(-1);
+
+ messagex(ctx, LOG_DEBUG, "sent email data");
+
+cleanup:
+
+ if(file != NULL)
+ fclose(file);
+
+ return ret;
+}
+
+static int read_server_response(clamsmtp_context_t* ctx)
+{
+ /* Read response line from the server */
+ if(read_line(ctx, &(ctx->server), 0) == -1)
+ return -1;
+
+ if(ctx->linelen == 0)
+ {
+ messagex(ctx, LOG_ERR, "server disconnected unexpectedly");
+
+ /* Tell the client it went wrong */
+ write_data(ctx, &(ctx->client), SMTP_FAILED);
+ return 0;
+ }
+
+ if(LINE_TOO_LONG(ctx))
+ messagex(ctx, LOG_WARNING, "SMTP response line too long. discarded extra");
+
+ return 0;
+}
+
+static void read_junk(clamsmtp_context_t* ctx, int fd)
+{
+ char buf[16];
+ const char* t;
+ int said = 0;
+ int l;
+
+ if(fd == -1)
+ return;
+
+ /* Make it non blocking */
+ fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
+
+ for(;;)
+ {
+ l = read(fd, buf, sizeof(buf) - 1);
+ if(l <= 0)
+ break;
+
+ buf[l] = 0;
+ t = buf;
+
+ while(*t && isspace(*t))
+ t++;
+
+ if(!said && *t)
+ {
+ messagex(ctx, LOG_WARNING, "received junk data from daemon");
+ said = 1;
+ }
+ }
+
+ fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
+}
+
+static int read_line(clamsmtp_context_t* ctx, int* fd, int trim)
+{
+ int l;
+ char* t;
+ const char* e;
+
+ if(*fd == -1)
+ {
+ messagex(ctx, LOG_WARNING, "tried to read from a closed connection");
+ return 0;
+ }
+
+ ctx->line[0] = 0;
+ e = ctx->line + (LINE_LENGTH - 1);
+
+ for(t = ctx->line; t < e; ++t)
+ {
+ l = read(*fd, (void*)t, sizeof(char));
+
+ /* We got a character */
+ if(l == 1)
+ {
+ /* End of line */
+ if(*t == '\n')
+ {
+ ++t;
+ break;
+ }
+
+ /* We skip spaces at the beginning if trimming */
+ if(trim && t == ctx->line && isspace(*t))
+ continue;
+ }
+
+ /* If it's the end of file then return that */
+ else if(l == 0)
+ {
+ /* Put in an extra line if there was anything */
+ if(t > ctx->line && !trim)
+ {
+ *t = '\n';
+ ++t;
+ }
+
+ break;
+ }
+
+ /* Transient errors */
+ else if(l == -1 && errno == EAGAIN)
+ continue;
+
+ /* Fatal errors */
+ else if(l == -1)
+ {
+ message(ctx, LOG_ERR, "couldn't read data");
+ return -1;
+ }
+ }
+
+ *t = 0;
+
+ if(trim)
+ {
+ while(t > ctx->line && isspace(*(t - 1)))
+ {
+ --t;
+ *t = 0;
+ }
+ }
+
+ ctx->linelen = t - ctx->line;
+ log_fd_data(ctx, ctx->line, fd, 1);
+
+ return ctx->linelen;
+}
+
+static int write_data_raw(clamsmtp_context_t* ctx, int* fd, unsigned char* buf, int len)
+{
+ int r;
+
+ while(len > 0)
+ {
+ r = write(*fd, buf, len);
+
+ if(r > 0)
+ {
+ buf += r;
+ len -= r;
+ }
+
+ else if(r == -1)
+ {
+ if(errno == EAGAIN)
+ continue;
+
+ if(errno == EPIPE)
+ {
+ shutdown(*fd, SHUT_RDWR);
+ *fd = -1;
+ }
+
+ message(ctx, LOG_ERR, "couldn't write data to socket");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int write_data(clamsmtp_context_t* ctx, int* fd, unsigned char* buf)
+{
+ int len = strlen(buf);
+
+ if(*fd == -1)
+ {
+ message(ctx, LOG_ERR, "connection closed. can't write data.");
+ return -1;
+ }
+
+ log_fd_data(ctx, buf, fd, 0);
+ return write_data_raw(ctx, fd, buf, len);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-25 08:18:46 +0000