smbd: reject FILE_ATTRIBUTE_TEMPORARY on directories

[Samba.git] / source3 / modules / vfs_preopen.c

/*
 * Force a readahead of files by opening them and reading the first bytes
 *
 * Copyright (C) Volker Lendecke 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "includes.h"
#include "system/filesys.h"
#include "smbd/smbd.h"
#include "lib/util/sys_rw.h"
#include "lib/util/sys_rw_data.h"
#include "lib/util/smb_strtox.h"
#include "lib/util_matching.h"
#include "lib/global_contexts.h"

static int vfs_preopen_debug_level = DBGC_VFS;

#undef DBGC_CLASS
#define DBGC_CLASS vfs_preopen_debug_level

#define PREOPEN_MAX_DIGITS 19
#define PREOPEN_MAX_NUMBER (uint64_t)9999999999999999999ULL

struct preopen_state;

struct preopen_helper {
        struct preopen_state *state;
        struct tevent_fd *fde;
        pid_t pid;
        int fd;
        bool busy;
};

struct preopen_state {
        int num_helpers;
        struct preopen_helper *helpers;

        size_t to_read;         /* How many bytes to read in children? */
        int queue_max;

        int queue_dbglvl;       /* DBGLVL_DEBUG by default */
        int nomatch_dbglvl;     /* DBGLVL_INFO by default */
        int match_dbglvl;       /* DBGLVL_INFO by default */
        int reset_dbglvl;       /* DBGLVL_INFO by default */
        int nodigits_dbglvl;    /* DBGLVL_WARNING by default */
        int founddigits_dbglvl; /* DBGLVL_NOTICE by default */
        int push_dbglvl;        /* DBGLVL_NOTICE by default */

        char *template_fname;   /* Filename to be sent to children */
        size_t number_start;    /* start offset into "template_fname" */
        int num_digits;         /* How many digits is the number long? */

        uint64_t fnum_sent;     /* last fname sent to children */

        uint64_t fnum_queue_end;/* last fname to be sent, based on
                                 * last open call + preopen:queuelen
                                 */

        struct samba_path_matching *preopen_names;
        ssize_t last_match_idx; /* remember the last match */
};

static void preopen_helper_destroy(struct preopen_helper *c)
{
        int status;
        TALLOC_FREE(c->fde);
        close(c->fd);
        c->fd = -1;
        kill(c->pid, SIGKILL);
        waitpid(c->pid, &status, 0);
        c->busy = true;
}

static void preopen_queue_run(struct preopen_state *state)
{
        char *pdelimiter;
        char delimiter;

        DBG_PREFIX(state->queue_dbglvl, ("START: "
                   "last_fname[%s] start_offset=%zu num_digits=%d "
                   "last_pushed_num=%"PRIu64" queue_end_num=%"PRIu64" num_helpers=%d\n",
                   state->template_fname,
                   state->number_start,
                   state->num_digits,
                   state->fnum_sent,
                   state->fnum_queue_end,
                   state->num_helpers));

        pdelimiter = state->template_fname + state->number_start
                + state->num_digits;
        delimiter = *pdelimiter;

        while (state->fnum_sent < state->fnum_queue_end) {

                ssize_t written;
                size_t to_write;
                int helper;

                for (helper=0; helper<state->num_helpers; helper++) {
                        if (state->helpers[helper].busy) {
                                continue;
                        }
                        break;
                }
                if (helper == state->num_helpers) {
                        /* everyone is busy */
                        DBG_PREFIX(state->queue_dbglvl, ("BUSY: "
                                   "template_fname[%s] start_offset=%zu num_digits=%d "
                                   "last_pushed_num=%"PRIu64" queue_end_num=%"PRIu64"\n",
                                   state->template_fname,
                                   state->number_start,
                                   state->num_digits,
                                   state->fnum_sent,
                                   state->fnum_queue_end));
                        return;
                }

                snprintf(state->template_fname + state->number_start,
                         state->num_digits + 1,
                         "%.*llu", state->num_digits,
                         (long long unsigned int)(state->fnum_sent + 1));
                *pdelimiter = delimiter;

                DBG_PREFIX(state->push_dbglvl, (
                           "PUSH: fullpath[%s] to helper(idx=%d)\n",
                           state->template_fname, helper));

                to_write = talloc_get_size(state->template_fname);
                written = write_data(state->helpers[helper].fd,
                                     state->template_fname, to_write);
                state->helpers[helper].busy = true;

                if (written != to_write) {
                        preopen_helper_destroy(&state->helpers[helper]);
                }
                state->fnum_sent += 1;
        }
        DBG_PREFIX(state->queue_dbglvl, ("END: "
                   "template_fname[%s] start_offset=%zu num_digits=%d "
                   "last_pushed_num=%"PRIu64" queue_end_num=%"PRIu64"\n",
                   state->template_fname,
                   state->number_start,
                   state->num_digits,
                   state->fnum_sent,
                   state->fnum_queue_end));
}

static void preopen_helper_readable(struct tevent_context *ev,
                                    struct tevent_fd *fde, uint16_t flags,
                                    void *priv)
{
        struct preopen_helper *helper = (struct preopen_helper *)priv;
        struct preopen_state *state = helper->state;
        ssize_t nread;
        char c;

        if ((flags & TEVENT_FD_READ) == 0) {
                return;
        }

        nread = read(helper->fd, &c, 1);
        if (nread <= 0) {
                preopen_helper_destroy(helper);
                return;
        }

        helper->busy = false;

        DBG_PREFIX(state->queue_dbglvl, ("BEFORE: preopen_queue_run\n"));
        preopen_queue_run(state);
        DBG_PREFIX(state->queue_dbglvl, ("AFTER: preopen_queue_run\n"));
}

static int preopen_helpers_destructor(struct preopen_state *c)
{
        int i;

        for (i=0; i<c->num_helpers; i++) {
                if (c->helpers[i].fd == -1) {
                        continue;
                }
                preopen_helper_destroy(&c->helpers[i]);
        }

        return 0;
}

static bool preopen_helper_open_one(int sock_fd, char **pnamebuf,
                                    size_t to_read, void *filebuf)
{
        char *namebuf = *pnamebuf;
        ssize_t nread;
        char c = 0;
        int fd;

        nread = 0;

        do {
                ssize_t thistime;

                thistime = read(sock_fd, namebuf + nread,
                                talloc_get_size(namebuf) - nread);
                if (thistime <= 0) {
                        return false;
                }

                nread += thistime;

                if (nread == talloc_get_size(namebuf)) {
                        namebuf = talloc_realloc(
                                NULL, namebuf, char,
                                talloc_get_size(namebuf) * 2);
                        if (namebuf == NULL) {
                                return false;
                        }
                        *pnamebuf = namebuf;
                }
        } while (namebuf[nread - 1] != '\0');

        fd = open(namebuf, O_RDONLY);
        if (fd == -1) {
                goto done;
        }
        nread = read(fd, filebuf, to_read);
        close(fd);

 done:
        sys_write_v(sock_fd, &c, 1);
        return true;
}

static bool preopen_helper(int fd, size_t to_read)
{
        char *namebuf;
        void *readbuf;

        namebuf = talloc_array(NULL, char, 1024);
        if (namebuf == NULL) {
                return false;
        }

        readbuf = talloc_size(NULL, to_read);
        if (readbuf == NULL) {
                TALLOC_FREE(namebuf);
                return false;
        }

        while (preopen_helper_open_one(fd, &namebuf, to_read, readbuf)) {
                ;
        }

        TALLOC_FREE(readbuf);
        TALLOC_FREE(namebuf);
        return false;
}

static NTSTATUS preopen_init_helper(struct preopen_helper *h)
{
        int fdpair[2];
        NTSTATUS status;

        if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
                status = map_nt_error_from_unix(errno);
                DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
                return status;
        }

        h->pid = fork();

        if (h->pid == -1) {
                return map_nt_error_from_unix(errno);
        }

        if (h->pid == 0) {
                close(fdpair[0]);
                preopen_helper(fdpair[1], h->state->to_read);
                exit(0);
        }
        close(fdpair[1]);
        h->fd = fdpair[0];
        h->fde = tevent_add_fd(global_event_context(), h->state, h->fd,
                              TEVENT_FD_READ, preopen_helper_readable, h);
        if (h->fde == NULL) {
                close(h->fd);
                h->fd = -1;
                return NT_STATUS_NO_MEMORY;
        }
        h->busy = false;
        return NT_STATUS_OK;
}

static NTSTATUS preopen_init_helpers(TALLOC_CTX *mem_ctx, size_t to_read,
                                     int num_helpers, int queue_max,
                                     struct preopen_state **presult)
{
        struct preopen_state *result;
        int i;

        result = talloc(mem_ctx, struct preopen_state);
        if (result == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        result->num_helpers = num_helpers;
        result->helpers = talloc_array(result, struct preopen_helper,
                                       num_helpers);
        if (result->helpers == NULL) {
                TALLOC_FREE(result);
                return NT_STATUS_NO_MEMORY;
        }

        result->to_read = to_read;
        result->queue_max = queue_max;
        result->template_fname = NULL;
        result->fnum_sent = 0;
        result->fnum_queue_end = 0;

        for (i=0; i<num_helpers; i++) {
                result->helpers[i].state = result;
                result->helpers[i].fd = -1;
        }

        talloc_set_destructor(result, preopen_helpers_destructor);

        for (i=0; i<num_helpers; i++) {
                preopen_init_helper(&result->helpers[i]);
        }

        *presult = result;
        return NT_STATUS_OK;
}

static void preopen_free_helpers(void **ptr)
{
        TALLOC_FREE(*ptr);
}

static struct preopen_state *preopen_state_get(vfs_handle_struct *handle)
{
        struct preopen_state *state;
        NTSTATUS status;
        const char *namelist;

        if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
                SMB_VFS_HANDLE_GET_DATA(handle, state, struct preopen_state,
                                        return NULL);
                return state;
        }

        namelist = lp_parm_const_string(SNUM(handle->conn), "preopen", "names",
                                        NULL);

        if (namelist == NULL) {
                return NULL;
        }

        status = preopen_init_helpers(
                NULL,
                lp_parm_int(SNUM(handle->conn), "preopen", "num_bytes", 1),
                lp_parm_int(SNUM(handle->conn), "preopen", "helpers", 1),
                lp_parm_int(SNUM(handle->conn), "preopen", "queuelen", 10),
                &state);
        if (!NT_STATUS_IS_OK(status)) {
                return NULL;
        }

        state->queue_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "queue_log_level", DBGLVL_DEBUG);
        state->nomatch_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "nomatch_log_level", DBGLVL_INFO);
        state->match_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "match_log_level", DBGLVL_INFO);
        state->reset_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "reset_log_level", DBGLVL_INFO);
        state->nodigits_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "nodigits_log_level", DBGLVL_WARNING);
        state->founddigits_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "founddigits_log_level", DBGLVL_NOTICE);
        state->push_dbglvl = lp_parm_int(SNUM(handle->conn), "preopen", "push_log_level", DBGLVL_NOTICE);

        if (lp_parm_bool(SNUM(handle->conn), "preopen", "posix-basic-regex", false)) {
                status = samba_path_matching_regex_sub1_create(state,
                                                               namelist,
                                                               &state->preopen_names);
        } else {
                status = samba_path_matching_mswild_create(state,
                                                           true, /* case_sensitive */
                                                           namelist,
                                                           &state->preopen_names);
        }
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(state);
                return NULL;
        }
        state->last_match_idx = -1;

        if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
                SMB_VFS_HANDLE_SET_DATA(handle, state, preopen_free_helpers,
                                        struct preopen_state, return NULL);
        }

        return state;
}

static bool preopen_parse_fname(const char *fname, uint64_t *pnum,
                                size_t *pstart_idx, int *pnum_digits)
{
        char digits[PREOPEN_MAX_DIGITS+1] = { 0, };
        const char *p;
        char *q = NULL;
        unsigned long long num;
        size_t start_idx = 0;
        int num_digits = -1;
        int error = 0;

        if (*pstart_idx > 0 && *pnum_digits > 0) {
                /*
                 * If the caller knowns
                 * how many digits are expected
                 * and on what position,
                 * we should copy the exact
                 * subset before we start
                 * parsing the string into a number
                 */

                if (*pnum_digits < 1) {
                        /*
                         * We need at least one digit
                         */
                        return false;
                }
                if (*pnum_digits > PREOPEN_MAX_DIGITS) {
                        /*
                         * a string with as much digits as
                         * PREOPEN_MAX_DIGITS is the longest
                         * string that would make any sense for us.
                         *
                         * The rest will be checked via
                         * smb_strtoull().
                         */
                        return false;
                }
                p = fname + *pstart_idx;
                memcpy(digits, p, *pnum_digits);
                p = digits;
                start_idx = *pstart_idx;
                goto parse;
        }

        p = strrchr_m(fname, '/');
        if (p == NULL) {
                p = fname;
        }

        p += 1;
        while (p[0] != '\0') {
                if (isdigit(p[0]) && isdigit(p[1]) && isdigit(p[2])) {
                        break;
                }
                p += 1;
        }
        if (*p == '\0') {
                /* no digits around */
                return false;
        }

        start_idx = (p - fname);

parse:
        num = smb_strtoull(p, (char **)&q, 10, &error, SMB_STR_STANDARD);
        if (error != 0) {
                return false;
        }

        if (num >= PREOPEN_MAX_NUMBER) {
                /* overflow */
                return false;
        }

        num_digits = (q - p);

        if (*pnum_digits != -1 && *pnum_digits != num_digits) {
                /*
                 * If the caller knowns how many digits
                 * it expects we should fail if we got something
                 * different.
                 */
                return false;
        }

        *pnum = num;
        *pstart_idx = start_idx;
        *pnum_digits = num_digits;
        return true;
}

static uint64_t num_digits_max_value(int num_digits)
{
        uint64_t num_max = 1;
        int i;

        if (num_digits < 1) {
                return 0;
        }
        if (num_digits >= PREOPEN_MAX_DIGITS) {
                return PREOPEN_MAX_NUMBER;
        }

        for (i = 0; i < num_digits; i++) {
                num_max *= 10;
        }

        /*
         * We actually want
         * 9   instead of 10
         * 99  instead of 100
         * 999 instead of 1000
         */
        return num_max - 1;
}

static int preopen_openat(struct vfs_handle_struct *handle,
                          const struct files_struct *dirfsp,
                          const struct smb_filename *smb_fname,
                          struct files_struct *fsp,
                          const struct vfs_open_how *how)
{
        const char *dirname = dirfsp->fsp_name->base_name;
        struct preopen_state *state;
        int res;
        uint64_t num;
        uint64_t num_max;
        NTSTATUS status;
        char *new_template = NULL;
        size_t new_start = 0;
        int new_digits = -1;
        size_t new_end = 0;
        ssize_t match_idx = -1;
        ssize_t replace_start = -1;
        ssize_t replace_end = -1;
        bool need_reset = false;

        DBG_DEBUG("called on %s\n", smb_fname_str_dbg(smb_fname));

        state = preopen_state_get(handle);
        if (state == NULL) {
                return SMB_VFS_NEXT_OPENAT(handle,
                                           dirfsp,
                                           smb_fname,
                                           fsp,
                                           how);
        }

        res = SMB_VFS_NEXT_OPENAT(handle, dirfsp, smb_fname, fsp, how);
        if (res == -1) {
                return -1;
        }

        if ((how->flags & O_ACCMODE) != O_RDONLY) {
                return res;
        }

        /*
         * Make sure we can later contruct an absolute pathname
         */
        if (dirname[0] != '/') {
                return res;
        }
        /*
         * There's no point in preopen the directory itself.
         */
        if (ISDOT(smb_fname->base_name)) {
                return res;
        }
        /*
         * If we got an absolute path in
         * smb_fname it's most likely the
         * reopen via /proc/self/fd/$fd
         */
        if (smb_fname->base_name[0] == '/') {
                return res;
        }

        status = samba_path_matching_check_last_component(state->preopen_names,
                                                          smb_fname->base_name,
                                                          &match_idx,
                                                          &replace_start,
                                                          &replace_end);
        if (!NT_STATUS_IS_OK(status)) {
                match_idx = -1;
        }
        if (match_idx < 0) {
                DBG_PREFIX(state->nomatch_dbglvl, (
                           "No match with the preopen:names list by name[%s]\n",
                           smb_fname_str_dbg(smb_fname)));
                return res;
        }

        if (replace_start != -1 && replace_end != -1) {
                DBG_PREFIX(state->match_dbglvl, (
                           "Pattern(idx=%zd) from preopen:names list matched name[%s] hints(start=%zd,end=%zd)\n",
                           match_idx, smb_fname_str_dbg(smb_fname), replace_start, replace_end));
        } else {
                DBG_PREFIX(state->match_dbglvl, (
                           "Pattern(idx=%zd) from preopen:names list matched name[%s]\n",
                           match_idx, smb_fname_str_dbg(smb_fname)));
        }

        new_template = talloc_asprintf(
                state, "%s/%s",
                dirname, smb_fname->base_name);
        if (new_template == NULL) {
                DBG_ERR("talloc_asprintf(%s/%s) failed\n",
                        dirname, smb_fname_str_dbg(smb_fname));
                return res;
        }

        if (replace_start != -1 && replace_end != -1) {
                size_t dirofs = strlen(dirname) + 1;
                new_start = dirofs + replace_start;
                new_digits = replace_end - replace_start;
        }

        if (!preopen_parse_fname(new_template, &num,
                                 &new_start, &new_digits)) {
                DBG_PREFIX(state->nodigits_dbglvl, (
                           "Pattern(idx=%zd) no valid digits found on fullpath[%s]\n",
                           match_idx, new_template));
                TALLOC_FREE(new_template);
                return res;
        }
        new_end = new_start + new_digits;

        DBG_PREFIX(state->founddigits_dbglvl, (
                   "Pattern(idx=%zd) found num_digits[%d] start_offset[%zd] parsed_num[%"PRIu64"] fullpath[%s]\n",
                   match_idx, new_digits, new_start, num, new_template));

        if (state->last_match_idx != match_idx) {
                /*
                 * If a different pattern caused the match
                 * we better reset the queue
                 */
                if (state->last_match_idx != -1) {
                        DBG_PREFIX(state->reset_dbglvl, ("RESET: "
                                   "pattern changed from idx=%zd to idx=%zd by fullpath[%s]\n",
                                   state->last_match_idx, match_idx, new_template));
                }
                need_reset = true;
        } else if (state->number_start != new_start) {
                /*
                 * If the digits started at a different possition
                 * we better reset the queue
                 */
                DBG_PREFIX(state->reset_dbglvl, ("RESET: "
                           "start_offset changed from byte=%zd to byte=%zd by fullpath[%s]\n",
                           state->number_start, new_start, new_template));
                need_reset = true;
        } else if (state->num_digits != new_digits) {
                /*
                 * If number of digits changed
                 * we better reset the queue
                 */
                DBG_PREFIX(state->reset_dbglvl, ("RESET: "
                           "num_digits changed %d to %d by fullpath[%s]\n",
                           state->num_digits, new_digits, new_template));
                need_reset = true;
        } else if (strncmp(state->template_fname, new_template, new_start) != 0) {
                /*
                 * If name before the digits changed
                 * we better reset the queue
                 */
                DBG_PREFIX(state->reset_dbglvl, ("RESET: "
                           "leading pathprefix[%.*s] changed by fullpath[%s]\n",
                           (int)state->number_start, state->template_fname, new_template));
                need_reset = true;
        } else if (strcmp(state->template_fname + new_end, new_template + new_end) != 0) {
                /*
                 * If name after the digits changed
                 * we better reset the queue
                 */
                DBG_PREFIX(state->reset_dbglvl, ("RESET: "
                           "trailing suffix[%s] changed by fullpath[%s]\n",
                           state->template_fname + new_end, new_template));
                need_reset = true;
        }

        if (need_reset) {
                /*
                 * Reset the queue
                 */
                state->fnum_sent = 0;
                state->fnum_queue_end = 0;
                state->last_match_idx = match_idx;
        }

        TALLOC_FREE(state->template_fname);
        state->template_fname = new_template;
        state->number_start = new_start;
        state->num_digits = new_digits;

        if (num > state->fnum_sent) {
                /*
                 * Helpers were too slow, there's no point in reading
                 * files in helpers that we already read in the
                 * parent.
                 */
                state->fnum_sent = num;
        }

        if ((state->fnum_queue_end != 0) /* Something was started earlier */
            && (num < (state->fnum_queue_end - state->queue_max))) {
                /*
                 * "num" is before the queue we announced. This means
                 * a new run is started.
                 */
                state->fnum_sent = num;
        }

        num_max = num_digits_max_value(state->num_digits);
        state->fnum_queue_end = MIN(num_max, num + state->queue_max);

        DBG_PREFIX(state->queue_dbglvl, ("BEFORE: preopen_queue_run\n"));
        preopen_queue_run(state);
        DBG_PREFIX(state->queue_dbglvl, ("AFTER: preopen_queue_run\n"));

        return res;
}

static struct vfs_fn_pointers vfs_preopen_fns = {
        .openat_fn = preopen_openat,
};

static_decl_vfs;
NTSTATUS vfs_preopen_init(TALLOC_CTX *ctx)
{
        NTSTATUS status;

        status = smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
                                  "preopen",
                                  &vfs_preopen_fns);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }

        vfs_preopen_debug_level = debug_add_class("preopen");
        if (vfs_preopen_debug_level == -1) {
                vfs_preopen_debug_level = DBGC_VFS;
                DBG_ERR("Couldn't register custom debugging class!\n");
        } else {
                DBG_DEBUG("Debug class number of 'preopen': %d\n",
                          vfs_preopen_debug_level);
        }

        return NT_STATUS_OK;
}