libexec/got-read-tag/got-read-tag.c

   1 /*
   2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <sys/types.h>
  18 #include <sys/queue.h>
  19 #include <sys/uio.h>
  20 #include <sys/time.h>
  21
  22 #include <stdint.h>
  23 #include <limits.h>
  24 #include <signal.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29 #include <zlib.h>
  30
  31 #include "got_compat.h"
  32
  33 #include "got_error.h"
  34 #include "got_object.h"
  35
  36 #include "got_lib_delta.h"
  37 #include "got_lib_inflate.h"
  38 #include "got_lib_object.h"
  39 #include "got_lib_object_parse.h"
  40 #include "got_lib_privsep.h"
  41 #include "got_lib_sha1.h"
  42
  43 static volatile sig_atomic_t sigint_received;
  44
  45 static void
  46 catch_sigint(int signo)
  47 {
  48         sigint_received = 1;
  49 }
  50
  51 static const struct got_error *
  52 read_tag_object(struct got_tag_object **tag, FILE *f,
  53     struct got_object_id *expected_id)
  54 {
  55         const struct got_error *err = NULL;
  56         struct got_object *obj = NULL;
  57         size_t len;
  58         uint8_t *p;
  59         struct got_inflate_checksum csum;
  60         SHA1_CTX sha1_ctx;
  61         struct got_object_id id;
  62
  63         SHA1Init(&sha1_ctx);
  64         memset(&csum, 0, sizeof(csum));
  65         csum.output_sha1 = &sha1_ctx;
  66
  67         err = got_inflate_to_mem(&p, &len, NULL, &csum, f);
  68         if (err)
  69                 return err;
  70
  71         SHA1Final(id.sha1, &sha1_ctx);
  72         if (memcmp(expected_id->sha1, id.sha1, SHA1_DIGEST_LENGTH) != 0) {
  73                 char buf[SHA1_DIGEST_STRING_LENGTH];
  74                 err = got_error_fmt(GOT_ERR_OBJ_CSUM,
  75                     "checksum failure for object %s",
  76                     got_sha1_digest_to_str(expected_id->sha1, buf,
  77                     sizeof(buf)));
  78                 goto done;
  79         }
  80
  81         err = got_object_parse_header(&obj, p, len);
  82         if (err)
  83                 goto done;
  84
  85         if (len < obj->hdrlen + obj->size) {
  86                 err = got_error(GOT_ERR_BAD_OBJ_DATA);
  87                 goto done;
  88         }
  89
  90         /* Skip object header. */
  91         len -= obj->hdrlen;
  92         err = got_object_parse_tag(tag, p + obj->hdrlen, len);
  93 done:
  94         free(p);
  95         if (obj)
  96                 got_object_close(obj);
  97         return err;
  98 }
  99
 100 int
 101 main(int argc, char *argv[])
 102 {
 103         const struct got_error *err = NULL;
 104         struct imsgbuf ibuf;
 105         size_t datalen;
 106
 107         signal(SIGINT, catch_sigint);
 108
 109         imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
 110
 111 #ifndef PROFILE
 112         /* revoke access to most system calls */
 113         if (pledge("stdio recvfd", NULL) == -1) {
 114                 err = got_error_from_errno("pledge");
 115                 got_privsep_send_error(&ibuf, err);
 116                 return 1;
 117         }
 118
 119         /* revoke fs access */
 120         if (landlock_no_fs() == -1) {
 121                 err = got_error_from_errno("landlock_no_fs");
 122                 got_privsep_send_error(&ibuf, err);
 123                 return 1;
 124         }
 125         if (cap_enter() == -1) {
 126                 err = got_error_from_errno("cap_enter");
 127                 got_privsep_send_error(&ibuf, err);
 128                 return 1;
 129         }
 130 #endif
 131
 132         for (;;) {
 133                 struct imsg imsg;
 134                 FILE *f = NULL;
 135                 struct got_tag_object *tag = NULL;
 136                 struct got_object_id expected_id;
 137
 138                 if (sigint_received) {
 139                         err = got_error(GOT_ERR_CANCELLED);
 140                         break;
 141                 }
 142
 143                 err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
 144                 if (err) {
 145                         if (err->code == GOT_ERR_PRIVSEP_PIPE)
 146                                 err = NULL;
 147                         break;
 148                 }
 149
 150                 if (imsg.hdr.type == GOT_IMSG_STOP)
 151                         break;
 152
 153                 if (imsg.hdr.type != GOT_IMSG_TAG_REQUEST) {
 154                         err = got_error(GOT_ERR_PRIVSEP_MSG);
 155                         goto done;
 156                 }
 157
 158                 datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
 159                 if (datalen != sizeof(expected_id)) {
 160                         err = got_error(GOT_ERR_PRIVSEP_LEN);
 161                         goto done;
 162                 }
 163                 memcpy(&expected_id, imsg.data, sizeof(expected_id));
 164
 165                 if (imsg.fd == -1) {
 166                         err = got_error(GOT_ERR_PRIVSEP_NO_FD);
 167                         goto done;
 168                 }
 169
 170                 /* Always assume file offset zero. */
 171                 f = fdopen(imsg.fd, "rb");
 172                 if (f == NULL) {
 173                         err = got_error_from_errno("fdopen");
 174                         goto done;
 175                 }
 176
 177                 err = read_tag_object(&tag, f, &expected_id);
 178                 if (err)
 179                         goto done;
 180
 181                 err = got_privsep_send_tag(&ibuf, tag);
 182 done:
 183                 if (f) {
 184                         if (fclose(f) == EOF && err == NULL)
 185                                 err = got_error_from_errno("fclose");
 186                 } else if (imsg.fd != -1) {
 187                         if (close(imsg.fd) == -1 && err == NULL)
 188                                 err = got_error_from_errno("close");
 189                 }
 190                 imsg_free(&imsg);
 191                 if (err)
 192                         break;
 193         }
 194
 195         imsg_clear(&ibuf);
 196         if (err) {
 197                 if (!sigint_received && err->code != GOT_ERR_PRIVSEP_PIPE) {
 198                         fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
 199                         got_privsep_send_error(&ibuf, err);
 200                 }
 201         }
 202         if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
 203                 err = got_error_from_errno("close");
 204         return err ? 1 : 0;
 205 }