Edit
IABSD.fr/src/usr.bin/ssh/sftp-server.c
djm
- usr.bin/ssh/sftp-server.c
-
/* $OpenBSD: sftp-server.c,v 1.154 2026/05/31 04:59:51 djm Exp $ */ /* * Copyright (c) 2000-2004 Markus Friedl. All rights reserved. * * 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 AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR 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/resource.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/statvfs.h> #include <dirent.h> #include <errno.h> #include <fcntl.h> #include <limits.h> #include <poll.h> #include <pwd.h> #include <grp.h> #include <stdlib.h> #include <stdio.h> #include <string.h> #include <time.h> #include <unistd.h> #include <stdarg.h> #include "atomicio.h" #include "xmalloc.h" #include "sshbuf.h" #include "ssherr.h" #include "log.h" #include "misc.h" #include "match.h" #include "uidswap.h" #include "sftp.h" #include "sftp-common.h" char *sftp_realpath(const char *, char *); /* sftp-realpath.c */ /* Maximum data read that we are willing to accept */ #define SFTP_MAX_READ_LENGTH (SFTP_MAX_MSG_LENGTH - 1024) /* Our verbosity */ static LogLevel log_level = SYSLOG_LEVEL_ERROR; /* Our client */ static struct passwd *pw = NULL; static char *client_addr = NULL; /* input and output queue */ struct sshbuf *iqueue; struct sshbuf *oqueue; /* Version of client */ static u_int version; /* SSH2_FXP_INIT received */ static int init_done; /* Disable writes */ static int readonly; /* Requests that are allowed/denied */ static char *request_allowlist, *request_denylist; /* portable attributes, etc. */ typedef struct Stat Stat; struct Stat { char *name; char *long_name; Attrib attrib; }; /* Packet handlers */ static void process_open(uint32_t id); static void process_close(uint32_t id); static void process_read(uint32_t id); static void process_write(uint32_t id); static void process_stat(uint32_t id); static void process_lstat(uint32_t id); static void process_fstat(uint32_t id); static void process_setstat(uint32_t id); static void process_fsetstat(uint32_t id); static void process_opendir(uint32_t id); static void process_readdir(uint32_t id); static void process_remove(uint32_t id); static void process_mkdir(uint32_t id); static void process_rmdir(uint32_t id); static void process_realpath(uint32_t id); static void process_rename(uint32_t id); static void process_readlink(uint32_t id); static void process_symlink(uint32_t id); static void process_extended_posix_rename(uint32_t id); static void process_extended_statvfs(uint32_t id); static void process_extended_fstatvfs(uint32_t id); static void process_extended_hardlink(uint32_t id); static void process_extended_fsync(uint32_t id); static void process_extended_lsetstat(uint32_t id); static void process_extended_limits(uint32_t id); static void process_extended_expand(uint32_t id); static void process_extended_copy_data(uint32_t id); static void process_extended_home_directory(uint32_t id); static void process_extended_get_users_groups_by_id(uint32_t id); static void process_extended(uint32_t id); struct sftp_handler { const char *name; /* user-visible name for fine-grained perms */ const char *ext_name; /* extended request name */ u_int type; /* packet type, for non extended packets */ void (*handler)(uint32_t); int does_write; /* if nonzero, banned for readonly mode */ }; static const struct sftp_handler handlers[] = { /* NB. SSH2_FXP_OPEN does the readonly check in the handler itself */ { "open", NULL, SSH2_FXP_OPEN, process_open, 0 }, { "close", NULL, SSH2_FXP_CLOSE, process_close, 0 }, { "read", NULL, SSH2_FXP_READ, process_read, 0 }, { "write", NULL, SSH2_FXP_WRITE, process_write, 1 }, { "lstat", NULL, SSH2_FXP_LSTAT, process_lstat, 0 }, { "fstat", NULL, SSH2_FXP_FSTAT, process_fstat, 0 }, { "setstat", NULL, SSH2_FXP_SETSTAT, process_setstat, 1 }, { "fsetstat", NULL, SSH2_FXP_FSETSTAT, process_fsetstat, 1 }, { "opendir", NULL, SSH2_FXP_OPENDIR, process_opendir, 0 }, { "readdir", NULL, SSH2_FXP_READDIR, process_readdir, 0 }, { "remove", NULL, SSH2_FXP_REMOVE, process_remove, 1 }, { "mkdir", NULL, SSH2_FXP_MKDIR, process_mkdir, 1 }, { "rmdir", NULL, SSH2_FXP_RMDIR, process_rmdir, 1 }, { "realpath", NULL, SSH2_FXP_REALPATH, process_realpath, 0 }, { "stat", NULL, SSH2_FXP_STAT, process_stat, 0 }, { "rename", NULL, SSH2_FXP_RENAME, process_rename, 1 }, { "readlink", NULL, SSH2_FXP_READLINK, process_readlink, 0 }, { "symlink", NULL, SSH2_FXP_SYMLINK, process_symlink, 1 }, { NULL, NULL, 0, NULL, 0 } }; /* SSH2_FXP_EXTENDED submessages */ static const struct sftp_handler extended_handlers[] = { { "posix-rename", "posix-rename@openssh.com", 0, process_extended_posix_rename, 1 }, { "statvfs", "statvfs@openssh.com", 0, process_extended_statvfs, 0 }, { "fstatvfs", "fstatvfs@openssh.com", 0, process_extended_fstatvfs, 0 }, { "hardlink", "hardlink@openssh.com", 0, process_extended_hardlink, 1 }, { "fsync", "fsync@openssh.com", 0, process_extended_fsync, 1 }, { "lsetstat", "lsetstat@openssh.com", 0, process_extended_lsetstat, 1 }, { "limits", "limits@openssh.com", 0, process_extended_limits, 0 }, { "expand-path", "expand-path@openssh.com", 0, process_extended_expand, 0 }, { "copy-data", "copy-data", 0, process_extended_copy_data, 1 }, { "home-directory", "home-directory", 0, process_extended_home_directory, 0 }, { "users-groups-by-id", "users-groups-by-id@openssh.com", 0, process_extended_get_users_groups_by_id, 0 }, { NULL, NULL, 0, NULL, 0 } }; static const struct sftp_handler * extended_handler_byname(const char *name) { int i; for (i = 0; extended_handlers[i].handler != NULL; i++) { if (strcmp(name, extended_handlers[i].ext_name) == 0) return &extended_handlers[i]; } return NULL; } static int request_permitted(const struct sftp_handler *h) { char *result; if (readonly && h->does_write) { verbose("Refusing %s request in read-only mode", h->name); return 0; } if (request_denylist != NULL && ((result = match_list(h->name, request_denylist, NULL))) != NULL) { free(result); verbose("Refusing denylisted %s request", h->name); return 0; } if (request_allowlist != NULL && ((result = match_list(h->name, request_allowlist, NULL))) != NULL) { free(result); debug2("Permitting allowlisted %s request", h->name); return 1; } if (request_allowlist != NULL) { verbose("Refusing non-allowlisted %s request", h->name); return 0; } return 1; } static int errno_to_portable(int unixerrno) { int ret = 0; switch (unixerrno) { case 0: ret = SSH2_FX_OK; break; case ENOENT: case ENOTDIR: case EBADF: case ELOOP: ret = SSH2_FX_NO_SUCH_FILE; break; case EPERM: case EACCES: case EFAULT: ret = SSH2_FX_PERMISSION_DENIED; break; case ENAMETOOLONG: case EINVAL: ret = SSH2_FX_BAD_MESSAGE; break; case ENOSYS: ret = SSH2_FX_OP_UNSUPPORTED; break; default: ret = SSH2_FX_FAILURE; break; } return ret; } static int flags_from_portable(int pflags) { int flags = 0; if ((pflags & SSH2_FXF_READ) && (pflags & SSH2_FXF_WRITE)) { flags = O_RDWR; } else if (pflags & SSH2_FXF_READ) { flags = O_RDONLY; } else if (pflags & SSH2_FXF_WRITE) { flags = O_WRONLY; } if (pflags & SSH2_FXF_APPEND) flags |= O_APPEND; if (pflags & SSH2_FXF_CREAT) flags |= O_CREAT; if (pflags & SSH2_FXF_TRUNC) flags |= O_TRUNC; if (pflags & SSH2_FXF_EXCL) flags |= O_EXCL; return flags; } static const char * string_from_portable(int pflags) { static char ret[128]; *ret = '\0'; #define PAPPEND(str) { \ if (*ret != '\0') \ strlcat(ret, ",", sizeof(ret)); \ strlcat(ret, str, sizeof(ret)); \ } if (pflags & SSH2_FXF_READ) PAPPEND("READ") if (pflags & SSH2_FXF_WRITE) PAPPEND("WRITE") if (pflags & SSH2_FXF_APPEND) PAPPEND("APPEND") if (pflags & SSH2_FXF_CREAT) PAPPEND("CREATE") if (pflags & SSH2_FXF_TRUNC) PAPPEND("TRUNCATE") if (pflags & SSH2_FXF_EXCL) PAPPEND("EXCL") return ret; } /* handle handles */ typedef struct Handle Handle; struct Handle { int use; DIR *dirp; int fd; int flags; char *name; uint64_t bytes_read, bytes_write; int next_unused; }; enum { HANDLE_UNUSED, HANDLE_DIR, HANDLE_FILE }; static Handle *handles = NULL; static u_int num_handles = 0; static int first_unused_handle = -1; static void handle_unused(int i) { handles[i].use = HANDLE_UNUSED; handles[i].next_unused = first_unused_handle; first_unused_handle = i; } static int handle_new(int use, const char *name, int fd, int flags, DIR *dirp) { int i; if (first_unused_handle == -1) { if (num_handles + 1 <= num_handles) return -1; num_handles++; handles = xreallocarray(handles, num_handles, sizeof(Handle)); handle_unused(num_handles - 1); } i = first_unused_handle; first_unused_handle = handles[i].next_unused; handles[i].use = use; handles[i].dirp = dirp; handles[i].fd = fd; handles[i].flags = flags; handles[i].name = xstrdup(name); handles[i].bytes_read = handles[i].bytes_write = 0; return i; } static int handle_is_ok(int i, int type) { return i >= 0 && (u_int)i < num_handles && handles[i].use == type; } static int handle_to_string(int handle, u_char **stringp, int *hlenp) { if (stringp == NULL || hlenp == NULL) return -1; *stringp = xmalloc(sizeof(int32_t)); put_u32(*stringp, handle); *hlenp = sizeof(int32_t); return 0; } static int handle_from_string(const u_char *handle, u_int hlen) { int val; if (hlen != sizeof(int32_t)) return -1; val = get_u32(handle); if (handle_is_ok(val, HANDLE_FILE) || handle_is_ok(val, HANDLE_DIR)) return val; return -1; } static char * handle_to_name(int handle) { if (handle_is_ok(handle, HANDLE_DIR)|| handle_is_ok(handle, HANDLE_FILE)) return handles[handle].name; return NULL; } static DIR * handle_to_dir(int handle) { if (handle_is_ok(handle, HANDLE_DIR)) return handles[handle].dirp; return NULL; } static int handle_to_fd(int handle) { if (handle_is_ok(handle, HANDLE_FILE)) return handles[handle].fd; return -1; } static int handle_to_flags(int handle) { if (handle_is_ok(handle, HANDLE_FILE)) return handles[handle].flags; return 0; } static void handle_update_read(int handle, ssize_t bytes) { if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0) handles[handle].bytes_read += bytes; } static void handle_update_write(int handle, ssize_t bytes) { if (handle_is_ok(handle, HANDLE_FILE) && bytes > 0) handles[handle].bytes_write += bytes; } static uint64_t handle_bytes_read(int handle) { if (handle_is_ok(handle, HANDLE_FILE)) return (handles[handle].bytes_read); return 0; } static uint64_t handle_bytes_write(int handle) { if (handle_is_ok(handle, HANDLE_FILE)) return (handles[handle].bytes_write); return 0; } static int handle_close(int handle) { int ret = -1; if (handle_is_ok(handle, HANDLE_FILE)) { ret = close(handles[handle].fd); free(handles[handle].name); handle_unused(handle); } else if (handle_is_ok(handle, HANDLE_DIR)) { ret = closedir(handles[handle].dirp); free(handles[handle].name); handle_unused(handle); } else { errno = ENOENT; } return ret; } static void handle_log_close(int handle, char *emsg) { if (handle_is_ok(handle, HANDLE_FILE)) { logit("%s%sclose \"%s\" bytes read %llu written %llu", emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ", handle_to_name(handle), (unsigned long long)handle_bytes_read(handle), (unsigned long long)handle_bytes_write(handle)); } else { logit("%s%sclosedir \"%s\"", emsg == NULL ? "" : emsg, emsg == NULL ? "" : " ", handle_to_name(handle)); } } static void handle_log_exit(void) { u_int i; for (i = 0; i < num_handles; i++) if (handles[i].use != HANDLE_UNUSED) handle_log_close(i, "forced"); } static int get_handle(struct sshbuf *queue, int *hp) { u_char *handle; int r; size_t hlen; *hp = -1; if ((r = sshbuf_get_string(queue, &handle, &hlen)) != 0) return r; if (hlen < 256) *hp = handle_from_string(handle, hlen); free(handle); return 0; } /* send replies */ static void send_msg(struct sshbuf *m) { int r; if ((r = sshbuf_put_stringb(oqueue, m)) != 0) fatal_fr(r, "enqueue"); sshbuf_reset(m); } static const char * status_to_message(uint32_t status) { static const char * const status_messages[] = { "Success", /* SSH_FX_OK */ "End of file", /* SSH_FX_EOF */ "No such file", /* SSH_FX_NO_SUCH_FILE */ "Permission denied", /* SSH_FX_PERMISSION_DENIED */ "Failure", /* SSH_FX_FAILURE */ "Bad message", /* SSH_FX_BAD_MESSAGE */ "No connection", /* SSH_FX_NO_CONNECTION */ "Connection lost", /* SSH_FX_CONNECTION_LOST */ "Operation unsupported", /* SSH_FX_OP_UNSUPPORTED */ "Unknown error" /* Others */ }; return (status_messages[MINIMUM(status,SSH2_FX_MAX)]); } static void send_status_errmsg(uint32_t id, uint32_t status, const char *errmsg) { struct sshbuf *msg; int r; debug3("request %u: sent status %u", id, status); if (log_level > SYSLOG_LEVEL_VERBOSE || (status != SSH2_FX_OK && status != SSH2_FX_EOF)) logit("sent status %s", status_to_message(status)); if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_STATUS)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = sshbuf_put_u32(msg, status)) != 0) fatal_fr(r, "compose"); if (version >= 3) { if ((r = sshbuf_put_cstring(msg, errmsg == NULL ? status_to_message(status) : errmsg)) != 0 || (r = sshbuf_put_cstring(msg, "")) != 0) fatal_fr(r, "compose message"); } send_msg(msg); sshbuf_free(msg); } static void send_status(uint32_t id, uint32_t status) { send_status_errmsg(id, status, NULL); } static void send_data_or_handle(char type, uint32_t id, const u_char *data, int dlen) { struct sshbuf *msg; int r; if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, type)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = sshbuf_put_string(msg, data, dlen)) != 0) fatal_fr(r, "compose"); send_msg(msg); sshbuf_free(msg); } static void send_data(uint32_t id, const u_char *data, int dlen) { debug("request %u: sent data len %d", id, dlen); send_data_or_handle(SSH2_FXP_DATA, id, data, dlen); } static void send_handle(uint32_t id, int handle) { u_char *string; int hlen; handle_to_string(handle, &string, &hlen); debug("request %u: sent handle %d", id, handle); send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen); free(string); } static void send_names(uint32_t id, int count, const Stat *stats) { struct sshbuf *msg; int i, r; if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_NAME)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = sshbuf_put_u32(msg, count)) != 0) fatal_fr(r, "compose"); debug("request %u: sent names count %d", id, count); for (i = 0; i < count; i++) { if ((r = sshbuf_put_cstring(msg, stats[i].name)) != 0 || (r = sshbuf_put_cstring(msg, stats[i].long_name)) != 0 || (r = encode_attrib(msg, &stats[i].attrib)) != 0) fatal_fr(r, "compose filenames/attrib"); } send_msg(msg); sshbuf_free(msg); } static void send_attrib(uint32_t id, const Attrib *a) { struct sshbuf *msg; int r; debug("request %u: sent attrib have 0x%x", id, a->flags); if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_ATTRS)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = encode_attrib(msg, a)) != 0) fatal_fr(r, "compose"); send_msg(msg); sshbuf_free(msg); } static void send_statvfs(uint32_t id, struct statvfs *st) { struct sshbuf *msg; uint64_t flag; int r; flag = (st->f_flag & ST_RDONLY) ? SSH2_FXE_STATVFS_ST_RDONLY : 0; flag |= (st->f_flag & ST_NOSUID) ? SSH2_FXE_STATVFS_ST_NOSUID : 0; if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = sshbuf_put_u64(msg, st->f_bsize)) != 0 || (r = sshbuf_put_u64(msg, st->f_frsize)) != 0 || (r = sshbuf_put_u64(msg, st->f_blocks)) != 0 || (r = sshbuf_put_u64(msg, st->f_bfree)) != 0 || (r = sshbuf_put_u64(msg, st->f_bavail)) != 0 || (r = sshbuf_put_u64(msg, st->f_files)) != 0 || (r = sshbuf_put_u64(msg, st->f_ffree)) != 0 || (r = sshbuf_put_u64(msg, st->f_favail)) != 0 || (r = sshbuf_put_u64(msg, st->f_fsid)) != 0 || (r = sshbuf_put_u64(msg, flag)) != 0 || (r = sshbuf_put_u64(msg, st->f_namemax)) != 0) fatal_fr(r, "compose"); send_msg(msg); sshbuf_free(msg); } /* * Prepare SSH2_FXP_VERSION extension advertisement for a single extension. * The extension is checked for permission prior to advertisement. */ static int compose_extension(struct sshbuf *msg, const char *name, const char *ver) { int r; const struct sftp_handler *exthnd; if ((exthnd = extended_handler_byname(name)) == NULL) fatal_f("internal error: no handler for %s", name); if (!request_permitted(exthnd)) { debug2_f("refusing to advertise disallowed extension %s", name); return 0; } if ((r = sshbuf_put_cstring(msg, name)) != 0 || (r = sshbuf_put_cstring(msg, ver)) != 0) fatal_fr(r, "compose %s", name); return 0; } /* parse incoming */ static void process_init(void) { struct sshbuf *msg; int r; if ((r = sshbuf_get_u32(iqueue, &version)) != 0) fatal_fr(r, "parse"); verbose("received client version %u", version); if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_VERSION)) != 0 || (r = sshbuf_put_u32(msg, SSH2_FILEXFER_VERSION)) != 0) fatal_fr(r, "compose"); /* extension advertisements */ compose_extension(msg, "posix-rename@openssh.com", "1"); compose_extension(msg, "statvfs@openssh.com", "2"); compose_extension(msg, "fstatvfs@openssh.com", "2"); compose_extension(msg, "hardlink@openssh.com", "1"); compose_extension(msg, "fsync@openssh.com", "1"); compose_extension(msg, "lsetstat@openssh.com", "1"); compose_extension(msg, "limits@openssh.com", "1"); compose_extension(msg, "expand-path@openssh.com", "1"); compose_extension(msg, "copy-data", "1"); compose_extension(msg, "home-directory", "1"); compose_extension(msg, "users-groups-by-id@openssh.com", "1"); send_msg(msg); sshbuf_free(msg); } static void process_open(uint32_t id) { uint32_t pflags; Attrib a; char *name; int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 || (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */ (r = decode_attrib(iqueue, &a)) != 0) fatal_fr(r, "parse"); debug3("request %u: open flags %d", id, pflags); flags = flags_from_portable(pflags); mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666; logit("open \"%s\" flags %s mode 0%o", name, string_from_portable(pflags), mode); if (readonly && ((flags & O_ACCMODE) != O_RDONLY || (flags & (O_CREAT|O_TRUNC)) != 0)) { verbose("Refusing open request in read-only mode"); status = SSH2_FX_PERMISSION_DENIED; } else { fd = open(name, flags, mode); if (fd == -1) { status = errno_to_portable(errno); } else { handle = handle_new(HANDLE_FILE, name, fd, flags, NULL); if (handle < 0) { close(fd); } else { send_handle(id, handle); status = SSH2_FX_OK; } } } if (status != SSH2_FX_OK) send_status(id, status); free(name); } static void process_close(uint32_t id) { int r, handle, ret, status = SSH2_FX_FAILURE; if ((r = get_handle(iqueue, &handle)) != 0) fatal_fr(r, "parse"); debug3("request %u: close handle %u", id, handle); handle_log_close(handle, NULL); ret = handle_close(handle); status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); } static void process_read(uint32_t id) { static u_char *buf; static size_t buflen; uint32_t len; int r, handle, fd, ret, status = SSH2_FX_FAILURE; uint64_t off; if ((r = get_handle(iqueue, &handle)) != 0 || (r = sshbuf_get_u64(iqueue, &off)) != 0 || (r = sshbuf_get_u32(iqueue, &len)) != 0) fatal_fr(r, "parse"); debug("request %u: read \"%s\" (handle %d) off %llu len %u", id, handle_to_name(handle), handle, (unsigned long long)off, len); if ((fd = handle_to_fd(handle)) == -1) goto out; if (len > SFTP_MAX_READ_LENGTH) { debug2("read change len %u to %u", len, SFTP_MAX_READ_LENGTH); len = SFTP_MAX_READ_LENGTH; } if (len > buflen) { debug3_f("allocate %zu => %u", buflen, len); if ((buf = realloc(buf, len)) == NULL) fatal_f("realloc failed"); buflen = len; } if (lseek(fd, off, SEEK_SET) == -1) { status = errno_to_portable(errno); error_f("seek \"%.100s\": %s", handle_to_name(handle), strerror(errno)); goto out; } if (len == 0) { /* weird, but not strictly disallowed */ ret = 0; } else if ((ret = read(fd, buf, len)) == -1) { status = errno_to_portable(errno); error_f("read \"%.100s\": %s", handle_to_name(handle), strerror(errno)); goto out; } else if (ret == 0) { status = SSH2_FX_EOF; goto out; } send_data(id, buf, ret); handle_update_read(handle, ret); /* success */ status = SSH2_FX_OK; out: if (status != SSH2_FX_OK) send_status(id, status); } static void process_write(uint32_t id) { uint64_t off; size_t len; int r, handle, fd, ret, status; u_char *data; if ((r = get_handle(iqueue, &handle)) != 0 || (r = sshbuf_get_u64(iqueue, &off)) != 0 || (r = sshbuf_get_string(iqueue, &data, &len)) != 0) fatal_fr(r, "parse"); debug("request %u: write \"%s\" (handle %d) off %llu len %zu", id, handle_to_name(handle), handle, (unsigned long long)off, len); fd = handle_to_fd(handle); if (fd < 0) status = SSH2_FX_FAILURE; else { if (!(handle_to_flags(handle) & O_APPEND) && lseek(fd, off, SEEK_SET) == -1) { status = errno_to_portable(errno); error_f("seek \"%.100s\": %s", handle_to_name(handle), strerror(errno)); } else { /* XXX ATOMICIO ? */ ret = write(fd, data, len); if (ret == -1) { status = errno_to_portable(errno); error_f("write \"%.100s\": %s", handle_to_name(handle), strerror(errno)); } else if ((size_t)ret == len) { status = SSH2_FX_OK; handle_update_write(handle, ret); } else { debug2_f("nothing at all written"); status = SSH2_FX_FAILURE; } } } send_status(id, status); free(data); } static void process_do_stat(uint32_t id, int do_lstat) { Attrib a; struct stat st; char *name; int r, status = SSH2_FX_FAILURE; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: %sstat", id, do_lstat ? "l" : ""); verbose("%sstat name \"%s\"", do_lstat ? "l" : "", name); r = do_lstat ? lstat(name, &st) : stat(name, &st); if (r == -1) { status = errno_to_portable(errno); } else { stat_to_attrib(&st, &a); send_attrib(id, &a); status = SSH2_FX_OK; } if (status != SSH2_FX_OK) send_status(id, status); free(name); } static void process_stat(uint32_t id) { process_do_stat(id, 0); } static void process_lstat(uint32_t id) { process_do_stat(id, 1); } static void process_fstat(uint32_t id) { Attrib a; struct stat st; int fd, r, handle, status = SSH2_FX_FAILURE; if ((r = get_handle(iqueue, &handle)) != 0) fatal_fr(r, "parse"); debug("request %u: fstat \"%s\" (handle %u)", id, handle_to_name(handle), handle); fd = handle_to_fd(handle); if (fd >= 0) { r = fstat(fd, &st); if (r == -1) { status = errno_to_portable(errno); } else { stat_to_attrib(&st, &a); send_attrib(id, &a); status = SSH2_FX_OK; } } if (status != SSH2_FX_OK) send_status(id, status); } static struct timeval * attrib_to_tv(const Attrib *a) { static struct timeval tv[2]; tv[0].tv_sec = a->atime; tv[0].tv_usec = 0; tv[1].tv_sec = a->mtime; tv[1].tv_usec = 0; return tv; } static struct timespec * attrib_to_ts(const Attrib *a) { static struct timespec ts[2]; ts[0].tv_sec = a->atime; ts[0].tv_nsec = 0; ts[1].tv_sec = a->mtime; ts[1].tv_nsec = 0; return ts; } static void process_setstat(uint32_t id) { Attrib a; char *name; int r, status = SSH2_FX_OK; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 || (r = decode_attrib(iqueue, &a)) != 0) fatal_fr(r, "parse"); debug("request %u: setstat name \"%s\"", id, name); if (a.flags & SSH2_FILEXFER_ATTR_SIZE) { logit("set \"%s\" size %llu", name, (unsigned long long)a.size); r = truncate(name, a.size); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) { logit("set \"%s\" mode %04o", name, a.perm); r = chmod(name, a.perm & 07777); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) { char buf[64]; time_t t = a.mtime; strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S", localtime(&t)); logit("set \"%s\" modtime %s", name, buf); r = utimes(name, attrib_to_tv(&a)); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) { logit("set \"%s\" owner %lu group %lu", name, (u_long)a.uid, (u_long)a.gid); r = chown(name, a.uid, a.gid); if (r == -1) status = errno_to_portable(errno); } send_status(id, status); free(name); } static void process_fsetstat(uint32_t id) { Attrib a; int handle, fd, r; int status = SSH2_FX_OK; if ((r = get_handle(iqueue, &handle)) != 0 || (r = decode_attrib(iqueue, &a)) != 0) fatal_fr(r, "parse"); debug("request %u: fsetstat handle %d", id, handle); fd = handle_to_fd(handle); if (fd < 0) status = SSH2_FX_FAILURE; else { char *name = handle_to_name(handle); if (a.flags & SSH2_FILEXFER_ATTR_SIZE) { logit("set \"%s\" size %llu", name, (unsigned long long)a.size); r = ftruncate(fd, a.size); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) { logit("set \"%s\" mode %04o", name, a.perm); r = fchmod(fd, a.perm & 07777); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) { char buf[64]; time_t t = a.mtime; strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S", localtime(&t)); logit("set \"%s\" modtime %s", name, buf); r = futimes(fd, attrib_to_tv(&a)); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) { logit("set \"%s\" owner %lu group %lu", name, (u_long)a.uid, (u_long)a.gid); r = fchown(fd, a.uid, a.gid); if (r == -1) status = errno_to_portable(errno); } } send_status(id, status); } static void process_opendir(uint32_t id) { DIR *dirp = NULL; char *path; int r, handle, status = SSH2_FX_FAILURE; if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: opendir", id); logit("opendir \"%s\"", path); dirp = opendir(path); if (dirp == NULL) { status = errno_to_portable(errno); } else { handle = handle_new(HANDLE_DIR, path, 0, 0, dirp); if (handle < 0) { closedir(dirp); } else { send_handle(id, handle); status = SSH2_FX_OK; } } if (status != SSH2_FX_OK) send_status(id, status); free(path); } static void process_readdir(uint32_t id) { DIR *dirp; struct dirent *dp; char *path; int r, handle; if ((r = get_handle(iqueue, &handle)) != 0) fatal_fr(r, "parse"); debug("request %u: readdir \"%s\" (handle %d)", id, handle_to_name(handle), handle); dirp = handle_to_dir(handle); path = handle_to_name(handle); if (dirp == NULL || path == NULL) { send_status(id, SSH2_FX_FAILURE); } else { struct stat st; char pathname[PATH_MAX]; Stat *stats; int nstats = 10, count = 0, i; stats = xcalloc(nstats, sizeof(Stat)); while ((dp = readdir(dirp)) != NULL) { if (count >= nstats) { nstats *= 2; stats = xreallocarray(stats, nstats, sizeof(Stat)); } /* XXX OVERFLOW ? */ snprintf(pathname, sizeof pathname, "%s%s%s", path, strcmp(path, "/") ? "/" : "", dp->d_name); if (lstat(pathname, &st) == -1) continue; stat_to_attrib(&st, &(stats[count].attrib)); stats[count].name = xstrdup(dp->d_name); stats[count].long_name = ls_file(dp->d_name, &st, 0, 0, NULL, NULL); count++; /* send up to 100 entries in one message */ /* XXX check packet size instead */ if (count == 100) break; } if (count > 0) { send_names(id, count, stats); for (i = 0; i < count; i++) { free(stats[i].name); free(stats[i].long_name); } } else { send_status(id, SSH2_FX_EOF); } free(stats); } } static void process_remove(uint32_t id) { char *name; int r, status = SSH2_FX_FAILURE; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: remove", id); logit("remove name \"%s\"", name); r = unlink(name); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(name); } static void process_mkdir(uint32_t id) { Attrib a; char *name; int r, mode, status = SSH2_FX_FAILURE; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 || (r = decode_attrib(iqueue, &a)) != 0) fatal_fr(r, "parse"); mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm & 07777 : 0777; debug3("request %u: mkdir", id); logit("mkdir name \"%s\" mode 0%o", name, mode); r = mkdir(name, mode); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(name); } static void process_rmdir(uint32_t id) { char *name; int r, status; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: rmdir", id); logit("rmdir name \"%s\"", name); r = rmdir(name); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(name); } static void process_realpath(uint32_t id) { char resolvedname[PATH_MAX]; char *path; int r; if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0) fatal_fr(r, "parse"); if (path[0] == '\0') { free(path); path = xstrdup("."); } debug3("request %u: realpath", id); verbose("realpath \"%s\"", path); if (sftp_realpath(path, resolvedname) == NULL) { send_status(id, errno_to_portable(errno)); } else { Stat s; attrib_clear(&s.attrib); s.name = s.long_name = resolvedname; send_names(id, 1, &s); } free(path); } static void process_rename(uint32_t id) { char *oldpath, *newpath; int r, status; struct stat sb; if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 || (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: rename", id); logit("rename old \"%s\" new \"%s\"", oldpath, newpath); status = SSH2_FX_FAILURE; if (lstat(oldpath, &sb) == -1) status = errno_to_portable(errno); else if (S_ISREG(sb.st_mode)) { /* Race-free rename of regular files */ if (link(oldpath, newpath) == -1) { if (errno == EOPNOTSUPP) { struct stat st; /* * fs doesn't support links, so fall back to * stat+rename. This is racy. */ if (stat(newpath, &st) == -1) { if (rename(oldpath, newpath) == -1) status = errno_to_portable(errno); else status = SSH2_FX_OK; } } else { status = errno_to_portable(errno); } } else if (unlink(oldpath) == -1) { status = errno_to_portable(errno); /* clean spare link */ unlink(newpath); } else status = SSH2_FX_OK; } else if (stat(newpath, &sb) == -1) { if (rename(oldpath, newpath) == -1) status = errno_to_portable(errno); else status = SSH2_FX_OK; } send_status(id, status); free(oldpath); free(newpath); } static void process_readlink(uint32_t id) { int r, len; char buf[PATH_MAX]; char *path; if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: readlink", id); verbose("readlink \"%s\"", path); if ((len = readlink(path, buf, sizeof(buf) - 1)) == -1) send_status(id, errno_to_portable(errno)); else { Stat s; buf[len] = '\0'; attrib_clear(&s.attrib); s.name = s.long_name = buf; send_names(id, 1, &s); } free(path); } static void process_symlink(uint32_t id) { char *oldpath, *newpath; int r, status; if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 || (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: symlink", id); logit("symlink old \"%s\" new \"%s\"", oldpath, newpath); /* this will fail if 'newpath' exists */ r = symlink(oldpath, newpath); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(oldpath); free(newpath); } static void process_extended_posix_rename(uint32_t id) { char *oldpath, *newpath; int r, status; if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 || (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: posix-rename", id); logit("posix-rename old \"%s\" new \"%s\"", oldpath, newpath); r = rename(oldpath, newpath); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(oldpath); free(newpath); } static void process_extended_statvfs(uint32_t id) { char *path; struct statvfs st; int r; if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: statvfs", id); logit("statvfs \"%s\"", path); if (statvfs(path, &st) != 0) send_status(id, errno_to_portable(errno)); else send_statvfs(id, &st); free(path); } static void process_extended_fstatvfs(uint32_t id) { int r, handle, fd; struct statvfs st; if ((r = get_handle(iqueue, &handle)) != 0) fatal_fr(r, "parse"); debug("request %u: fstatvfs \"%s\" (handle %u)", id, handle_to_name(handle), handle); if ((fd = handle_to_fd(handle)) < 0) { send_status(id, SSH2_FX_FAILURE); return; } if (fstatvfs(fd, &st) != 0) send_status(id, errno_to_portable(errno)); else send_statvfs(id, &st); } static void process_extended_hardlink(uint32_t id) { char *oldpath, *newpath; int r, status; if ((r = sshbuf_get_cstring(iqueue, &oldpath, NULL)) != 0 || (r = sshbuf_get_cstring(iqueue, &newpath, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: hardlink", id); logit("hardlink old \"%s\" new \"%s\"", oldpath, newpath); r = link(oldpath, newpath); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; send_status(id, status); free(oldpath); free(newpath); } static void process_extended_fsync(uint32_t id) { int handle, fd, r, status = SSH2_FX_OP_UNSUPPORTED; if ((r = get_handle(iqueue, &handle)) != 0) fatal_fr(r, "parse"); debug3("request %u: fsync (handle %u)", id, handle); verbose("fsync \"%s\"", handle_to_name(handle)); if ((fd = handle_to_fd(handle)) < 0) status = SSH2_FX_NO_SUCH_FILE; else if (handle_is_ok(handle, HANDLE_FILE)) { r = fsync(fd); status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK; } send_status(id, status); } static void process_extended_lsetstat(uint32_t id) { Attrib a; char *name; int r, status = SSH2_FX_OK; if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 || (r = decode_attrib(iqueue, &a)) != 0) fatal_fr(r, "parse"); debug("request %u: lsetstat name \"%s\"", id, name); if (a.flags & SSH2_FILEXFER_ATTR_SIZE) { /* nonsensical for links */ status = SSH2_FX_BAD_MESSAGE; goto out; } if (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) { logit("set \"%s\" mode %04o", name, a.perm); r = fchmodat(AT_FDCWD, name, a.perm & 07777, AT_SYMLINK_NOFOLLOW); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_ACMODTIME) { char buf[64]; time_t t = a.mtime; strftime(buf, sizeof(buf), "%Y%m%d-%H:%M:%S", localtime(&t)); logit("set \"%s\" modtime %s", name, buf); r = utimensat(AT_FDCWD, name, attrib_to_ts(&a), AT_SYMLINK_NOFOLLOW); if (r == -1) status = errno_to_portable(errno); } if (a.flags & SSH2_FILEXFER_ATTR_UIDGID) { logit("set \"%s\" owner %lu group %lu", name, (u_long)a.uid, (u_long)a.gid); r = fchownat(AT_FDCWD, name, a.uid, a.gid, AT_SYMLINK_NOFOLLOW); if (r == -1) status = errno_to_portable(errno); } out: send_status(id, status); free(name); } static void process_extended_limits(uint32_t id) { struct sshbuf *msg; int r; uint64_t nfiles = 0; struct rlimit rlim; debug("request %u: limits", id); if (getrlimit(RLIMIT_NOFILE, &rlim) != -1 && rlim.rlim_cur > 5) nfiles = rlim.rlim_cur - 5; /* stdio(3) + syslog + spare */ if ((msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || /* max-packet-length */ (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH)) != 0 || /* max-read-length */ (r = sshbuf_put_u64(msg, SFTP_MAX_READ_LENGTH)) != 0 || /* max-write-length */ (r = sshbuf_put_u64(msg, SFTP_MAX_MSG_LENGTH - 1024)) != 0 || /* max-open-handles */ (r = sshbuf_put_u64(msg, nfiles)) != 0) fatal_fr(r, "compose"); send_msg(msg); sshbuf_free(msg); } static void process_extended_expand(uint32_t id) { char cwd[PATH_MAX], resolvedname[PATH_MAX]; char *path, *npath; int r; Stat s; if ((r = sshbuf_get_cstring(iqueue, &path, NULL)) != 0) fatal_fr(r, "parse"); if (getcwd(cwd, sizeof(cwd)) == NULL) { send_status(id, errno_to_portable(errno)); goto out; } debug3("request %u: expand, original \"%s\"", id, path); if (path[0] == '\0') { /* empty path */ free(path); path = xstrdup("."); } else if (*path == '~') { /* ~ expand path */ /* Special-case for "~" and "~/" to respect homedir flag */ if (strcmp(path, "~") == 0) { free(path); path = xstrdup(cwd); } else if (strncmp(path, "~/", 2) == 0) { npath = xstrdup(path + 2); free(path); xasprintf(&path, "%s/%s", cwd, npath); free(npath); } else { /* ~user expansions */ if (tilde_expand(path, pw->pw_uid, &npath) != 0) { send_status_errmsg(id, errno_to_portable(ENOENT), "no such user"); goto out; } free(path); path = npath; } } else if (*path != '/') { /* relative path */ xasprintf(&npath, "%s/%s", cwd, path); free(path); path = npath; } verbose("expand \"%s\"", path); if (sftp_realpath(path, resolvedname) == NULL) { send_status(id, errno_to_portable(errno)); goto out; } attrib_clear(&s.attrib); s.name = s.long_name = resolvedname; send_names(id, 1, &s); out: free(path); } static void process_extended_copy_data(uint32_t id) { u_char buf[64*1024]; int read_handle, read_fd, write_handle, write_fd; uint64_t len, read_off, read_len, write_off; int r, copy_until_eof, status = SSH2_FX_OP_UNSUPPORTED; size_t ret; struct stat st_read, st_write; if ((r = get_handle(iqueue, &read_handle)) != 0 || (r = sshbuf_get_u64(iqueue, &read_off)) != 0 || (r = sshbuf_get_u64(iqueue, &read_len)) != 0 || (r = get_handle(iqueue, &write_handle)) != 0 || (r = sshbuf_get_u64(iqueue, &write_off)) != 0) fatal_fr(r, "buffer error"); debug("request %u: copy-data from \"%s\" (handle %d) off %llu len %llu " "to \"%s\" (handle %d) off %llu", id, handle_to_name(read_handle), read_handle, (unsigned long long)read_off, (unsigned long long)read_len, handle_to_name(write_handle), write_handle, (unsigned long long)write_off); /* For read length of 0, we read until EOF. */ if (read_len == 0) { read_len = (uint64_t)-1 - read_off; copy_until_eof = 1; } else copy_until_eof = 0; /* Disallow reading & writing to the same handle, path or inode */ read_fd = handle_to_fd(read_handle); write_fd = handle_to_fd(write_handle); if (fstat(read_fd, &st_read) != 0) { status = errno_to_portable(errno); error_f("fstat read_fd failed: %s", strerror(errno)); goto out; } if (fstat(write_fd, &st_write) != 0) { status = errno_to_portable(errno); error_f("fstat write_fd failed: %s", strerror(errno)); goto out; } if (read_handle == write_handle || read_fd < 0 || write_fd < 0 || !strcmp(handle_to_name(read_handle), handle_to_name(write_handle)) || (st_read.st_dev != 0 && st_read.st_ino != 0 && st_read.st_dev == st_write.st_dev && st_read.st_ino == st_write.st_ino)) { error_f("refusing to read/write same file: " "read \"%s\" dev %lu ino %lu, write \"%s\" dev %lu ino %lu", handle_to_name(read_handle), (u_long)st_read.st_dev, (u_long)st_read.st_ino, handle_to_name(write_handle), (u_long)st_write.st_dev, (u_long)st_write.st_ino); status = SSH2_FX_FAILURE; goto out; } if (lseek(read_fd, read_off, SEEK_SET) < 0) { status = errno_to_portable(errno); error_f("read_seek failed"); goto out; } if ((handle_to_flags(write_handle) & O_APPEND) == 0 && lseek(write_fd, write_off, SEEK_SET) < 0) { status = errno_to_portable(errno); error_f("write_seek failed"); goto out; } /* Process the request in chunks. */ while (read_len > 0 || copy_until_eof) { len = MINIMUM(sizeof(buf), read_len); read_len -= len; ret = atomicio(read, read_fd, buf, len); if (ret == 0 && errno == EPIPE) { status = copy_until_eof ? SSH2_FX_OK : SSH2_FX_EOF; break; } else if (ret == 0) { status = errno_to_portable(errno); error_f("read failed: %s", strerror(errno)); break; } len = ret; handle_update_read(read_handle, len); ret = atomicio(vwrite, write_fd, buf, len); if (ret != len) { status = errno_to_portable(errno); error("%s: write failed: %llu != %llu: %s", __func__, (unsigned long long)ret, (unsigned long long)len, strerror(errno)); break; } handle_update_write(write_handle, len); } if (read_len == 0) status = SSH2_FX_OK; out: send_status(id, status); } static void process_extended_home_directory(uint32_t id) { char *username; struct passwd *user_pw; int r; Stat s; if ((r = sshbuf_get_cstring(iqueue, &username, NULL)) != 0) fatal_fr(r, "parse"); debug3("request %u: home-directory \"%s\"", id, username); if (username[0] == '\0') { user_pw = pw; } else if ((user_pw = getpwnam(username)) == NULL) { send_status(id, SSH2_FX_FAILURE); goto out; } verbose("home-directory \"%s\"", user_pw->pw_dir); attrib_clear(&s.attrib); s.name = s.long_name = user_pw->pw_dir; send_names(id, 1, &s); out: free(username); } static void process_extended_get_users_groups_by_id(uint32_t id) { struct passwd *user_pw; struct group *gr; struct sshbuf *uids, *gids, *usernames, *groupnames, *msg; int r; u_int n, nusers = 0, ngroups = 0; const char *name; if ((usernames = sshbuf_new()) == NULL || (groupnames = sshbuf_new()) == NULL || (msg = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((r = sshbuf_froms(iqueue, &uids)) != 0 || (r = sshbuf_froms(iqueue, &gids)) != 0) fatal_fr(r, "parse"); debug_f("uids len = %zu, gids len = %zu", sshbuf_len(uids), sshbuf_len(gids)); while (sshbuf_len(uids) != 0) { if ((r = sshbuf_get_u32(uids, &n)) != 0) fatal_fr(r, "parse inner uid"); user_pw = getpwuid((uid_t)n); name = user_pw == NULL ? "" : user_pw->pw_name; debug3_f("uid %u => \"%s\"", n, name); if ((r = sshbuf_put_cstring(usernames, name)) != 0) fatal_fr(r, "assemble uid reply"); nusers++; } while (sshbuf_len(gids) != 0) { if ((r = sshbuf_get_u32(gids, &n)) != 0) fatal_fr(r, "parse inner gid"); gr = getgrgid((gid_t)n); name = gr == NULL ? "" : gr->gr_name; debug3_f("gid %u => \"%s\"", n, name); if ((r = sshbuf_put_cstring(groupnames, name)) != 0) fatal_fr(r, "assemble gid reply"); ngroups++; } verbose("users-groups-by-id: %u users, %u groups", nusers, ngroups); if ((r = sshbuf_put_u8(msg, SSH2_FXP_EXTENDED_REPLY)) != 0 || (r = sshbuf_put_u32(msg, id)) != 0 || (r = sshbuf_put_stringb(msg, usernames)) != 0 || (r = sshbuf_put_stringb(msg, groupnames)) != 0) fatal_fr(r, "compose"); send_msg(msg); sshbuf_free(uids); sshbuf_free(gids); sshbuf_free(usernames); sshbuf_free(groupnames); sshbuf_free(msg); } static void process_extended(uint32_t id) { char *request; int r; const struct sftp_handler *exthand; if ((r = sshbuf_get_cstring(iqueue, &request, NULL)) != 0) fatal_fr(r, "parse"); if ((exthand = extended_handler_byname(request)) == NULL) { error("Unknown extended request \"%.100s\"", request); send_status(id, SSH2_FX_OP_UNSUPPORTED); /* MUST */ } else { if (!request_permitted(exthand)) send_status(id, SSH2_FX_PERMISSION_DENIED); else exthand->handler(id); } free(request); } /* stolen from ssh-agent */ static void process(void) { u_int msg_len; u_int buf_len; u_int consumed; u_char type; const u_char *cp; int i, r; uint32_t id; buf_len = sshbuf_len(iqueue); if (buf_len < 5) return; /* Incomplete message. */ cp = sshbuf_ptr(iqueue); msg_len = get_u32(cp); if (msg_len > SFTP_MAX_MSG_LENGTH) { error("bad message from %s local user %s", client_addr, pw->pw_name); sftp_server_cleanup_exit(11); } if (buf_len < msg_len + 4) return; if ((r = sshbuf_consume(iqueue, 4)) != 0) fatal_fr(r, "consume"); buf_len -= 4; if ((r = sshbuf_get_u8(iqueue, &type)) != 0) fatal_fr(r, "parse type"); switch (type) { case SSH2_FXP_INIT: process_init(); init_done = 1; break; case SSH2_FXP_EXTENDED: if (!init_done) fatal("Received extended request before init"); if ((r = sshbuf_get_u32(iqueue, &id)) != 0) fatal_fr(r, "parse extended ID"); process_extended(id); break; default: if (!init_done) fatal("Received %u request before init", type); if ((r = sshbuf_get_u32(iqueue, &id)) != 0) fatal_fr(r, "parse ID"); for (i = 0; handlers[i].handler != NULL; i++) { if (type == handlers[i].type) { if (!request_permitted(&handlers[i])) { send_status(id, SSH2_FX_PERMISSION_DENIED); } else { handlers[i].handler(id); } break; } } if (handlers[i].handler == NULL) error("Unknown message %u", type); } /* discard the remaining bytes from the current packet */ if (buf_len < sshbuf_len(iqueue)) { error("iqueue grew unexpectedly"); sftp_server_cleanup_exit(255); } consumed = buf_len - sshbuf_len(iqueue); if (msg_len < consumed) { error("msg_len %u < consumed %u", msg_len, consumed); sftp_server_cleanup_exit(255); } if (msg_len > consumed && (r = sshbuf_consume(iqueue, msg_len - consumed)) != 0) fatal_fr(r, "consume"); } /* Cleanup handler that logs active handles upon normal exit */ void sftp_server_cleanup_exit(int i) { if (pw != NULL && client_addr != NULL) { handle_log_exit(); logit("session closed for local user %s from [%s]", pw->pw_name, client_addr); } _exit(i); } static void sftp_server_usage(void) { extern char *__progname; fprintf(stderr, "usage: %s [-ehR] [-d start_directory] [-f log_facility] " "[-l log_level]\n\t[-P denied_requests] " "[-p allowed_requests] [-u umask]\n" " %s -Q protocol_feature\n", __progname, __progname); exit(1); } int sftp_server_main(int argc, char **argv, struct passwd *user_pw) { int i, r, in, out, ch, skipargs = 0, log_stderr = 0; ssize_t len, olen; SyslogFacility log_facility = SYSLOG_FACILITY_AUTH; char *cp, *homedir = NULL, uidstr[32], buf[4*4096]; long mask; extern char *optarg; extern char *__progname; log_init(__progname, log_level, log_facility, log_stderr); pw = pwcopy(user_pw); while (!skipargs && (ch = getopt(argc, argv, "d:f:l:P:p:Q:u:cehR")) != -1) { switch (ch) { case 'Q': if (strcasecmp(optarg, "requests") != 0) { fprintf(stderr, "Invalid query type\n"); exit(1); } for (i = 0; handlers[i].handler != NULL; i++) printf("%s\n", handlers[i].name); for (i = 0; extended_handlers[i].handler != NULL; i++) printf("%s\n", extended_handlers[i].name); exit(0); break; case 'R': readonly = 1; break; case 'c': /* * Ignore all arguments if we are invoked as a * shell using "sftp-server -c command" */ skipargs = 1; break; case 'e': log_stderr = 1; break; case 'l': log_level = log_level_number(optarg); if (log_level == SYSLOG_LEVEL_NOT_SET) error("Invalid log level \"%s\"", optarg); break; case 'f': log_facility = log_facility_number(optarg); if (log_facility == SYSLOG_FACILITY_NOT_SET) error("Invalid log facility \"%s\"", optarg); break; case 'd': cp = tilde_expand_filename(optarg, user_pw->pw_uid); snprintf(uidstr, sizeof(uidstr), "%llu", (unsigned long long)pw->pw_uid); homedir = percent_expand(cp, "d", user_pw->pw_dir, "u", user_pw->pw_name, "U", uidstr, (char *)NULL); free(cp); break; case 'p': if (request_allowlist != NULL) fatal("Permitted requests already set"); request_allowlist = xstrdup(optarg); break; case 'P': if (request_denylist != NULL) fatal("Refused requests already set"); request_denylist = xstrdup(optarg); break; case 'u': errno = 0; mask = strtol(optarg, &cp, 8); if (mask < 0 || mask > 0777 || *cp != '\0' || cp == optarg || (mask == 0 && errno != 0)) fatal("Invalid umask \"%s\"", optarg); (void)umask((mode_t)mask); break; case 'h': default: sftp_server_usage(); } } log_init(__progname, log_level, log_facility, log_stderr); if ((cp = getenv("SSH_CONNECTION")) != NULL) { client_addr = xstrdup(cp); if ((cp = strchr(client_addr, ' ')) == NULL) { error("Malformed SSH_CONNECTION variable: \"%s\"", getenv("SSH_CONNECTION")); sftp_server_cleanup_exit(255); } *cp = '\0'; } else client_addr = xstrdup("UNKNOWN"); logit("session opened for local user %s from [%s]", pw->pw_name, client_addr); in = STDIN_FILENO; out = STDOUT_FILENO; if ((iqueue = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if ((oqueue = sshbuf_new()) == NULL) fatal_f("sshbuf_new failed"); if (homedir != NULL) { if (chdir(homedir) != 0) { error("chdir to \"%s\" failed: %s", homedir, strerror(errno)); } } for (;;) { struct pollfd pfd[2]; memset(pfd, 0, sizeof pfd); pfd[0].fd = pfd[1].fd = -1; /* * Ensure that we can read a full buffer and handle * the worst-case length packet it can generate, * otherwise apply backpressure by stopping reads. */ if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 && (r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH)) == 0) { pfd[0].fd = in; pfd[0].events = POLLIN; } else if (r != SSH_ERR_NO_BUFFER_SPACE) fatal_fr(r, "reserve"); olen = sshbuf_len(oqueue); if (olen > 0) { pfd[1].fd = out; pfd[1].events = POLLOUT; } if (poll(pfd, 2, -1) == -1) { if (errno == EINTR) continue; error("poll: %s", strerror(errno)); sftp_server_cleanup_exit(2); } /* copy stdin to iqueue */ if (pfd[0].revents & (POLLIN|POLLHUP)) { len = read(in, buf, sizeof buf); if (len == 0) { debug("read eof"); sftp_server_cleanup_exit(0); } else if (len == -1) { if (errno != EAGAIN && errno != EINTR) { error("read: %s", strerror(errno)); sftp_server_cleanup_exit(1); } } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) fatal_fr(r, "sshbuf_put"); } /* send oqueue to stdout */ if (pfd[1].revents & (POLLOUT|POLLHUP)) { len = write(out, sshbuf_ptr(oqueue), olen); if (len == 0 || (len == -1 && errno == EPIPE)) { debug("write eof"); sftp_server_cleanup_exit(0); } else if (len == -1) { sftp_server_cleanup_exit(1); if (errno != EAGAIN && errno != EINTR) { error("write: %s", strerror(errno)); sftp_server_cleanup_exit(1); } } else if ((r = sshbuf_consume(oqueue, len)) != 0) fatal_fr(r, "consume"); } /* * Process requests from client if we can fit the results * into the output buffer, otherwise stop processing input * and let the output queue drain. */ r = sshbuf_check_reserve(oqueue, SFTP_MAX_MSG_LENGTH); if (r == 0) process(); else if (r != SSH_ERR_NO_BUFFER_SPACE) fatal_fr(r, "reserve"); } }