From 724e44eed299c618066dec411530aa9f156119ec Mon Sep 17 00:00:00 2001 From: Karolin Seeger Date: Sun, 27 Feb 2011 18:28:29 +0100 Subject: [PATCH] Fix denial of service - memory corruption. CVE-2011-0719 Fix bug #7949 (DoS in Winbind and smbd with many file descriptors open). All current released versions of Samba are vulnerable to a denial of service caused by memory corruption. Range checks on file descriptors being used in the FD_SET macro were not present allowing stack corruption. This can cause the Samba code to crash or to loop attempting to select on a bad file descriptor set. A connection to a file share, or a local account is needed to exploit this problem, either authenticated or unauthenticated (guest connection). Currently we do not believe this flaw is exploitable beyond a crash or causing the code to loop, but on the advice of our security reviewers we are releasing fixes in case an exploit is discovered at a later date. --- source/client/client.c | 4 +++- source/client/dnsbrowse.c | 12 ++++++++++++ source/lib/events.c | 13 +++++++++++++ source/lib/packet.c | 5 +++++ source/lib/readline.c | 5 +++++ source/lib/select.c | 6 ++++++ source/lib/util_sock.c | 11 +++++++++-- source/libaddns/dnssock.c | 6 +++++- source/libsmb/nmblib.c | 5 +++++ source/nmbd/nmbd_packets.c | 24 ++++++++++++++++++++++-- source/nsswitch/wb_common.c | 22 ++++++++++++++++++++-- source/printing/printing.c | 5 +++++ source/smbd/dnsregister.c | 6 ++++++ source/smbd/oplock.c | 5 ++++- source/smbd/oplock_irix.c | 5 +++++ source/smbd/process.c | 2 +- source/smbd/server.c | 29 +++++++++++++++++++++-------- source/utils/smbfilter.c | 8 ++++++-- source/winbindd/winbindd.c | 12 +++++++++++- source/winbindd/winbindd_dual.c | 7 +++++++ 20 files changed, 171 insertions(+), 21 deletions(-) diff --git a/source/client/client.c b/source/client/client.c index 53bd9e6..a989441 100644 --- a/source/client/client.c +++ b/source/client/client.c @@ -4379,8 +4379,10 @@ static void readline_callback(void) again: - if (cli->fd == -1) + if (cli->fd < 0 || cli->fd >= FD_SETSIZE) { + errno = EBADF; return; + } FD_ZERO(&fds); FD_SET(cli->fd,&fds); diff --git a/source/client/dnsbrowse.c b/source/client/dnsbrowse.c index 5e3a4de..aa2fb22 100644 --- a/source/client/dnsbrowse.c +++ b/source/client/dnsbrowse.c @@ -81,6 +81,11 @@ static void do_smb_resolve(struct mdns_smbsrv_result *browsesrv) TALLOC_FREE(fdset); } + if (mdnsfd < 0 || mdnsfd >= FD_SETSIZE) { + errno = EBADF; + break; + } + fdsetsz = howmany(mdnsfd + 1, NFDBITS) * sizeof(fd_mask); fdset = TALLOC_ZERO(ctx, fdsetsz); FD_SET(mdnsfd, fdset); @@ -183,6 +188,13 @@ int do_smb_browse(void) fdsetsz = howmany(mdnsfd + 1, NFDBITS) * sizeof(fd_mask); fdset = TALLOC_ZERO(ctx, fdsetsz); + + if (mdnsfd < 0 || mdnsfd >= FD_SETSIZE) { + errno = EBADF; + TALLOC_FREE(ctx); + return 1; + } + FD_SET(mdnsfd, fdset); tv.tv_sec = 1; diff --git a/source/lib/events.c b/source/lib/events.c index cd20ceb..2ddbab7 100644 --- a/source/lib/events.c +++ b/source/lib/events.c @@ -140,6 +140,11 @@ struct fd_event *event_add_fd(struct event_context *event_ctx, { struct fd_event *fde; + if (fd < 0 || fd >= FD_SETSIZE) { + errno = EBADF; + return NULL; + } + if (!(fde = TALLOC_P(mem_ctx, struct fd_event))) { return NULL; } @@ -190,6 +195,14 @@ bool event_add_to_select_args(struct event_context *event_ctx, bool ret = False; for (fde = event_ctx->fd_events; fde; fde = fde->next) { + if (fde->fd < 0 || fde->fd >= FD_SETSIZE) { + /* We ignore here, as it shouldn't be + possible to add an invalid fde->fd + but we don't want FD_SET to see an + invalid fd. */ + continue; + } + if (fde->flags & EVENT_FD_READ) { FD_SET(fde->fd, read_fds); ret = True; diff --git a/source/lib/packet.c b/source/lib/packet.c index e048616..512c7f2 100644 --- a/source/lib/packet.c +++ b/source/lib/packet.c @@ -106,6 +106,11 @@ NTSTATUS packet_fd_read_sync(struct packet_context *ctx) int res; fd_set r_fds; + if (ctx->fd < 0 || ctx->fd >= FD_SETSIZE) { + errno = EBADF; + return map_nt_error_from_unix(errno); + } + FD_ZERO(&r_fds); FD_SET(ctx->fd, &r_fds); diff --git a/source/lib/readline.c b/source/lib/readline.c index 34867aa..70a82f2 100644 --- a/source/lib/readline.c +++ b/source/lib/readline.c @@ -91,6 +91,11 @@ static char *smb_readline_replacement(const char *prompt, void (*callback)(void) timeout.tv_sec = 5; timeout.tv_usec = 0; + if (fd < 0 || fd >= FD_SETSIZE) { + errno = EBADF; + break; + } + FD_ZERO(&fds); FD_SET(fd,&fds); diff --git a/source/lib/select.c b/source/lib/select.c index c3da6a9..2d5f02c 100644 --- a/source/lib/select.c +++ b/source/lib/select.c @@ -61,6 +61,11 @@ int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, s if (pipe(select_pipe) == -1) smb_panic("Could not create select pipe"); + if (select_pipe[0] < 0 || select_pipe[0] >= FD_SETSIZE) { + errno = EBADF; + return -1; + } + /* * These next two lines seem to fix a bug with the Linux * 2.0.x kernel (and probably other UNIXes as well) where @@ -87,6 +92,7 @@ int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, s readfds2 = &readfds_buf; FD_ZERO(readfds2); } + FD_SET(select_pipe[0], readfds2); errno = 0; diff --git a/source/lib/util_sock.c b/source/lib/util_sock.c index 650bd13..8aa2c97 100644 --- a/source/lib/util_sock.c +++ b/source/lib/util_sock.c @@ -960,6 +960,11 @@ NTSTATUS read_socket_with_timeout(int fd, char *buf, timeout.tv_usec = (long)(1000 * (time_out % 1000)); for (nread=0; nread < mincnt; ) { + if (fd < 0 || fd >= FD_SETSIZE) { + errno = EBADF; + return map_nt_error_from_unix(EBADF); + } + FD_ZERO(&fds); FD_SET(fd,&fds); @@ -1492,7 +1497,7 @@ bool open_any_socket_out(struct sockaddr_storage *addrs, int num_addrs, for (i=0; i= FD_SETSIZE) goto done; set_blocking(sockets[i], false); } @@ -1541,8 +1546,10 @@ bool open_any_socket_out(struct sockaddr_storage *addrs, int num_addrs, FD_ZERO(&r_fds); for (i=0; i= FD_SETSIZE) { + /* This cannot happen - ignore if so. */ continue; + } FD_SET(sockets[i], &wr_fds); FD_SET(sockets[i], &r_fds); if (sockets[i]>maxfd) diff --git a/source/libaddns/dnssock.c b/source/libaddns/dnssock.c index 7c8bd41..f427bd5 100644 --- a/source/libaddns/dnssock.c +++ b/source/libaddns/dnssock.c @@ -218,7 +218,11 @@ static DNS_ERROR read_all(int fd, uint8 *data, size_t len) while (total < len) { ssize_t ret; int fd_ready; - + + if (fd < 0 || fd >= FD_SETSIZE) { + return ERROR_DNS_SOCKET_ERROR; + } + FD_ZERO( &rfds ); FD_SET( fd, &rfds ); diff --git a/source/libsmb/nmblib.c b/source/libsmb/nmblib.c index bfe5e7b..768e54d 100644 --- a/source/libsmb/nmblib.c +++ b/source/libsmb/nmblib.c @@ -1097,6 +1097,11 @@ struct packet_struct *receive_packet(int fd,enum packet_type type,int t) struct timeval timeout; int ret; + if (fd < 0 || fd >= FD_SETSIZE) { + errno = EBADF; + return NULL; + } + FD_ZERO(&fds); FD_SET(fd,&fds); timeout.tv_sec = t/1000; diff --git a/source/nmbd/nmbd_packets.c b/source/nmbd/nmbd_packets.c index 4b97819..03e5362 100644 --- a/source/nmbd/nmbd_packets.c +++ b/source/nmbd/nmbd_packets.c @@ -1683,7 +1683,7 @@ static bool create_listen_fdset(fd_set **ppset, int **psock_array, int *listen_n for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) count++; - if((count*2) + 2 > FD_SETSIZE) { + if((count*2) + 2 >= FD_SETSIZE) { DEBUG(0,("create_listen_fdset: Too many file descriptors needed (%d). We can \ only use %d.\n", (count*2) + 2, FD_SETSIZE)); SAFE_FREE(pset); @@ -1699,24 +1699,44 @@ only use %d.\n", (count*2) + 2, FD_SETSIZE)); FD_ZERO(pset); /* Add in the broadcast socket on 137. */ + if (ClientNMB < 0 || ClientNMB >= FD_SETSIZE) { + errno = EBADF; + SAFE_FREE(pset); + return True; + } + FD_SET(ClientNMB,pset); sock_array[num++] = ClientNMB; *maxfd = MAX( *maxfd, ClientNMB); /* Add in the 137 sockets on all the interfaces. */ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) { + if (subrec->nmb_sock < 0 || subrec->nmb_sock >= FD_SETSIZE) { + /* We have to ignore sockets outside FD_SETSIZE. */ + continue; + } FD_SET(subrec->nmb_sock,pset); sock_array[num++] = subrec->nmb_sock; *maxfd = MAX( *maxfd, subrec->nmb_sock); } /* Add in the broadcast socket on 138. */ + if (ClientDGRAM < 0 || ClientDGRAM >= FD_SETSIZE) { + errno = EBADF; + SAFE_FREE(pset); + return True; + } + FD_SET(ClientDGRAM,pset); sock_array[num++] = ClientDGRAM; *maxfd = MAX( *maxfd, ClientDGRAM); /* Add in the 138 sockets on all the interfaces. */ for (subrec = FIRST_SUBNET; subrec; subrec = NEXT_SUBNET_EXCLUDING_UNICAST(subrec)) { + if (subrec->dgram_sock < 0 || subrec->dgram_sock >= FD_SETSIZE) { + /* We have to ignore sockets outside FD_SETSIZE. */ + continue; + } FD_SET(subrec->dgram_sock,pset); sock_array[num++] = subrec->dgram_sock; *maxfd = MAX( *maxfd, subrec->dgram_sock); @@ -1767,7 +1787,7 @@ bool listen_for_packets(bool run_election) #ifndef SYNC_DNS dns_fd = asyncdns_fd(); - if (dns_fd != -1) { + if (dns_fd >= 0 && dns_fd < FD_SETSIZE) { FD_SET(dns_fd, &r_fds); maxfd = MAX( maxfd, dns_fd); } diff --git a/source/nsswitch/wb_common.c b/source/nsswitch/wb_common.c index a164621..4f76bd0 100644 --- a/source/nsswitch/wb_common.c +++ b/source/nsswitch/wb_common.c @@ -240,6 +240,12 @@ static int winbind_named_pipe_sock(const char *dir) switch (errno) { case EINPROGRESS: + + if (fd < 0 || fd >= FD_SETSIZE) { + errno = EBADF; + goto error_out; + } + FD_ZERO(&w_fds); FD_SET(fd, &w_fds); tv.tv_sec = CONNECT_TIMEOUT - wait_time; @@ -383,7 +389,13 @@ int winbind_write_sock(void *buffer, int count, int recursing, int need_priv) while(nwritten < count) { struct timeval tv; fd_set r_fds; - + + if (winbindd_fd < 0 || winbindd_fd >= FD_SETSIZE) { + errno = EBADF; + winbind_close_sock(); + return -1; + } + /* Catch pipe close on other end by checking if a read() call would not block by calling select(). */ @@ -443,7 +455,13 @@ int winbind_read_sock(void *buffer, int count) while(nread < count) { struct timeval tv; fd_set r_fds; - + + if (winbindd_fd < 0 || winbindd_fd >= FD_SETSIZE) { + errno = EBADF; + winbind_close_sock(); + return -1; + } + /* Catch pipe close on other end by checking if a read() call would not block by calling select(). */ diff --git a/source/printing/printing.c b/source/printing/printing.c index a9272eb..c3b8c61 100644 --- a/source/printing/printing.c +++ b/source/printing/printing.c @@ -1407,6 +1407,11 @@ void start_background_queue(void) exit(1); } + if (pause_pipe[1] < 0 || pause_pipe[1] >= FD_SETSIZE) { + DEBUG(5,("start_background_queue: pipe fd out of range.\n")); + exit(1); + } + background_lpq_updater_pid = sys_fork(); if (background_lpq_updater_pid == -1) { diff --git a/source/smbd/dnsregister.c b/source/smbd/dnsregister.c index f02739e..3c689b9 100644 --- a/source/smbd/dnsregister.c +++ b/source/smbd/dnsregister.c @@ -125,6 +125,9 @@ void dns_register_smbd(struct dns_reg_state ** dns_state_ptr, */ if (dns_state->srv_ref != NULL) { mdnsd_conn_fd = DNSServiceRefSockFD(dns_state->srv_ref); + if (mdnsd_conn_fd < 0 || mdnsd_conn_fd >= FD_SETSIZE) { + return; + } FD_SET(mdnsd_conn_fd, listen_set); return; } @@ -156,6 +159,9 @@ void dns_register_smbd(struct dns_reg_state ** dns_state_ptr, } mdnsd_conn_fd = DNSServiceRefSockFD(dns_state->srv_ref); + if (mdnsd_conn_fd < 0 || mdnsd_conn_fd >= FD_SETSIZE) { + return; + } FD_SET(mdnsd_conn_fd, listen_set); *maxfd = MAX(*maxfd, mdnsd_conn_fd); *timeout = timeval_zero(); diff --git a/source/smbd/oplock.c b/source/smbd/oplock.c index a07d05d..5ae3fdf 100644 --- a/source/smbd/oplock.c +++ b/source/smbd/oplock.c @@ -241,7 +241,10 @@ bool downgrade_oplock(files_struct *fsp) int oplock_notify_fd(void) { if (koplocks) { - return koplocks->notification_fd; + int fd = koplocks->notification_fd; + if (fd < 0 || fd >= FD_SETSIZE) { + return -1; + } } return -1; diff --git a/source/smbd/oplock_irix.c b/source/smbd/oplock_irix.c index 8c287c9..6e86fac 100644 --- a/source/smbd/oplock_irix.c +++ b/source/smbd/oplock_irix.c @@ -284,6 +284,11 @@ struct kernel_oplocks *irix_init_kernel_oplocks(void) return False; } + if (pfd[0] < 0 || pfd[0] >= FD_SETSIZE) { + DEBUG(0,("setup_kernel_oplock_pipe: fd out of range.\n")); + return False; + } + oplock_pipe_read = pfd[0]; oplock_pipe_write = pfd[1]; diff --git a/source/smbd/process.c b/source/smbd/process.c index 403c7c6..9b8f29b 100644 --- a/source/smbd/process.c +++ b/source/smbd/process.c @@ -698,7 +698,7 @@ static void async_processing(fd_set *pfds) static int select_on_fd(int fd, int maxfd, fd_set *fds) { - if (fd != -1) { + if (fd != -1 && fd < FD_SETSIZE) { FD_SET(fd, fds); maxfd = MAX(maxfd, fd); } diff --git a/source/smbd/server.c b/source/smbd/server.c index 5129484..a670334 100644 --- a/source/smbd/server.c +++ b/source/smbd/server.c @@ -209,7 +209,13 @@ static bool open_sockets_inetd(void) /* Started from inetd. fd 0 is the socket. */ /* We will abort gracefully when the client or remote system goes away */ - smbd_set_server_fd(dup(0)); + int fd = dup(0); + + if (fd < 0 || fd >= FD_SETSIZE) { + return false; + } + + smbd_set_server_fd(fd); /* close our standard file descriptors */ close_low_fds(False); /* Don't close stderr */ @@ -436,7 +442,8 @@ static bool open_sockets_smbd(bool is_daemon, bool interactive, const char *smb_ num_sockets == 0 ? 0 : 2, ifss, true); - if(s == -1) { + if(s < 0 || s >= FD_SETSIZE) { + close(s); continue; } @@ -516,7 +523,7 @@ static bool open_sockets_smbd(bool is_daemon, bool interactive, const char *smb_ num_sockets == 0 ? 0 : 2, &ss, true); - if (s == -1) { + if (s < 0 || s >= FD_SETSIZE) { continue; } @@ -709,6 +716,7 @@ static bool open_sockets_smbd(bool is_daemon, bool interactive, const char *smb_ struct sockaddr addr; socklen_t in_addrlen = sizeof(addr); pid_t child = 0; + int fd; s = -1; for(i = 0; i < num_sockets; i++) { @@ -721,16 +729,21 @@ static bool open_sockets_smbd(bool is_daemon, bool interactive, const char *smb_ } } - smbd_set_server_fd(accept(s,&addr,&in_addrlen)); - - if (smbd_server_fd() == -1 && errno == EINTR) + fd = accept(s,&addr,&in_addrlen); + if (fd == -1 && errno == EINTR) continue; - - if (smbd_server_fd() == -1) { + if (fd == -1) { DEBUG(2,("open_sockets_smbd: accept: %s\n", strerror(errno))); continue; } + if (fd < 0 || fd >= FD_SETSIZE) { + DEBUG(2,("open_sockets_smbd: bad fd %d\n", + fd )); + continue; + } + + smbd_set_server_fd(fd); /* Ensure child is set to blocking mode */ set_blocking(smbd_server_fd(),True); diff --git a/source/utils/smbfilter.c b/source/utils/smbfilter.c index 1e22a40..45f9207 100644 --- a/source/utils/smbfilter.c +++ b/source/utils/smbfilter.c @@ -162,8 +162,8 @@ static void filter_child(int c, struct sockaddr_storage *dest_ss) int num; FD_ZERO(&fds); - if (s != -1) FD_SET(s, &fds); - if (c != -1) FD_SET(c, &fds); + if (s >= 0 && s < FD_SETSIZE) FD_SET(s, &fds); + if (c >= 0 && c < FD_SETSIZE) FD_SET(c, &fds); num = sys_select_intr(MAX(s+1, c+1),&fds,NULL,NULL,NULL); if (num <= 0) continue; @@ -235,6 +235,10 @@ static void start_filter(char *desthost) struct sockaddr_storage ss; socklen_t in_addrlen = sizeof(ss); + if (s < 0 || s >= FD_SETSIZE) { + break; + } + FD_ZERO(&fds); FD_SET(s, &fds); diff --git a/source/winbindd/winbindd.c b/source/winbindd/winbindd.c index 1d618e2..6b5c251 100644 --- a/source/winbindd/winbindd.c +++ b/source/winbindd/winbindd.c @@ -836,7 +836,8 @@ static void process_loop(void) listen_sock = open_winbindd_socket(); listen_priv_sock = open_winbindd_priv_socket(); - if (listen_sock == -1 || listen_priv_sock == -1) { + if (listen_sock < 0 || listen_sock >= FD_SETSIZE || + listen_priv_sock < 0 || listen_priv_sock >= FD_SETSIZE) { perror("open_winbind_socket"); exit(1); } @@ -861,6 +862,9 @@ static void process_loop(void) FD_ZERO(&r_fds); FD_ZERO(&w_fds); + + /* We check the range for listen_sock and + listen_priv_sock above. */ FD_SET(listen_sock, &r_fds); FD_SET(listen_priv_sock, &r_fds); @@ -890,6 +894,12 @@ static void process_loop(void) } for (ev = fd_events; ev; ev = ev->next) { + if (ev->fd < 0 || ev->fd >= FD_SETSIZE) { + /* Ignore here - event_add_to_select_args + should make this impossible. */ + continue; + } + if (ev->flags & EVENT_FD_READ) { FD_SET(ev->fd, &r_fds); maxfd = MAX(ev->fd, maxfd); diff --git a/source/winbindd/winbindd_dual.c b/source/winbindd/winbindd_dual.c index ff004f2..b30ec20 100644 --- a/source/winbindd/winbindd_dual.c +++ b/source/winbindd/winbindd_dual.c @@ -1250,6 +1250,12 @@ static bool fork_domain_child(struct winbindd_child *child) return False; } + if (fdpair[0] < 0 || fdpair[0] >= FD_SETSIZE) { + DEBUG(0, ("fork_domain_child: bad fd range (%d)\n", fdpair[0])); + errno = EBADF; + return False; + } + ZERO_STRUCT(state); state.pid = sys_getpid(); @@ -1405,6 +1411,7 @@ static bool fork_domain_child(struct winbindd_child *child) message_dispatch(winbind_messaging_context()); FD_ZERO(&read_fds); + /* We check state.sock against FD_SETSIZE above. */ FD_SET(state.sock, &read_fds); ret = sys_select(state.sock + 1, &read_fds, NULL, NULL, tp); -- 1.6.4.2