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      1 /*      $NetBSD: psbuf.c,v 1.20 2025/12/22 16:30:49 nia Exp $        */
      2 
      3 /*
      4  * Copyright (c) 2006-2009  Antti Kantee.  All Rights Reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  * SUCH DAMAGE.
     26  */
     27 
     28 #include <sys/cdefs.h>
     29 #ifndef lint
     30 __RCSID("$NetBSD: psbuf.c,v 1.20 2025/12/22 16:30:49 nia Exp $");
     31 #endif /* !lint */
     32 
     33 /*
     34  * buffering functions for network input/output.  slightly different
     35  * from the average joe buffer routines, as is usually the case ...
     36  * these use efuns for now.
     37  */
     38 
     39 #include <sys/types.h>
     40 #include <sys/time.h>
     41 #include <sys/vnode.h>
     42 #include <sys/socket.h>
     43 
     44 #include <err.h>
     45 #include <errno.h>
     46 #include <endian.h>
     47 #include <stdlib.h>
     48 #include <util.h>
     49 #include <unistd.h>
     50 
     51 #include "psshfs.h"
     52 #include "sftp_proto.h"
     53 
     54 #define FAILRV(x) do { int rv; if ((rv=x)) return (rv); } while (/*CONSTCOND*/0)
     55 #define READSTATE_LENGTH(off) (off < 4)
     56 
     57 #define SFTP_LENOFF	0
     58 #define SFTP_TYPEOFF	4
     59 #define SFTP_REQIDOFF	5
     60 
     61 #define CHECK(v) if (!(v)) abort()
     62 
     63 uint8_t
     64 psbuf_get_type(struct puffs_framebuf *pb)
     65 {
     66 	uint8_t type;
     67 
     68 	puffs_framebuf_getdata_atoff(pb, SFTP_TYPEOFF, &type, 1);
     69 	return type;
     70 }
     71 
     72 uint32_t
     73 psbuf_get_len(struct puffs_framebuf *pb)
     74 {
     75 	uint32_t len;
     76 
     77 	puffs_framebuf_getdata_atoff(pb, SFTP_LENOFF, &len, 4);
     78 	return be32toh(len);
     79 }
     80 
     81 uint32_t
     82 psbuf_get_reqid(struct puffs_framebuf *pb)
     83 {
     84 	uint32_t req;
     85 
     86 	puffs_framebuf_getdata_atoff(pb, SFTP_REQIDOFF, &req, 4);
     87 	return be32toh(req);
     88 }
     89 
     90 #define CUROFF(pb) (puffs_framebuf_telloff(pb))
     91 int
     92 psbuf_read(struct puffs_usermount *pu, struct puffs_framebuf *pb,
     93 	int fd, int *done)
     94 {
     95 	void *win;
     96 	ssize_t n;
     97 	size_t howmuch, winlen;
     98 	int lenstate;
     99 
    100  the_next_level:
    101 	if ((lenstate = READSTATE_LENGTH(CUROFF(pb))))
    102 		howmuch = 4 - CUROFF(pb);
    103 	else
    104 		howmuch = psbuf_get_len(pb) - (CUROFF(pb) - 4);
    105 
    106 	if (puffs_framebuf_reserve_space(pb, howmuch) == -1)
    107 		return errno;
    108 
    109 	while (howmuch) {
    110 		winlen = howmuch;
    111 		if (puffs_framebuf_getwindow(pb, CUROFF(pb), &win, &winlen)==-1)
    112 			return errno;
    113 		n = recv(fd, win, winlen, MSG_NOSIGNAL);
    114 		switch (n) {
    115 		case 0:
    116 			return ECONNRESET;
    117 		case -1:
    118 			if (errno == EAGAIN)
    119 				return 0;
    120 			return errno;
    121 		default:
    122 			howmuch -= n;
    123 			puffs_framebuf_seekset(pb, CUROFF(pb) + n);
    124 			break;
    125 		}
    126 	}
    127 
    128 	if (!lenstate) {
    129 		/* XXX: initial exchange shorter.. but don't worry, be happy */
    130 		puffs_framebuf_seekset(pb, 9);
    131 		*done = 1;
    132 		return 0;
    133 	} else
    134 		goto the_next_level;
    135 }
    136 
    137 int
    138 psbuf_write(struct puffs_usermount *pu, struct puffs_framebuf *pb,
    139 	int fd, int *done)
    140 {
    141 	void *win;
    142 	ssize_t n;
    143 	size_t winlen, howmuch;
    144 
    145 	/* finalize buffer.. could be elsewhere ... */
    146 	if (CUROFF(pb) == 0) {
    147 		uint32_t len;
    148 
    149 		len = htobe32(puffs_framebuf_tellsize(pb) - 4);
    150 		puffs_framebuf_putdata_atoff(pb, 0, &len, 4);
    151 	}
    152 
    153 	howmuch = puffs_framebuf_tellsize(pb) - CUROFF(pb);
    154 	while (howmuch) {
    155 		winlen = howmuch;
    156 		if (puffs_framebuf_getwindow(pb, CUROFF(pb), &win, &winlen)==-1)
    157 			return errno;
    158 		n = send(fd, win, winlen, MSG_NOSIGNAL);
    159 		switch (n) {
    160 		case 0:
    161 			return ECONNRESET;
    162 		case -1:
    163 			if (errno == EAGAIN)
    164 				return 0;
    165 			return errno;
    166 		default:
    167 			howmuch -= n;
    168 			puffs_framebuf_seekset(pb, CUROFF(pb) + n);
    169 			break;
    170 		}
    171 	}
    172 
    173 	*done = 1;
    174 	return 0;
    175 }
    176 #undef CUROFF
    177 
    178 int
    179 psbuf_cmp(struct puffs_usermount *pu,
    180 	struct puffs_framebuf *cmp1, struct puffs_framebuf *cmp2, int *notresp)
    181 {
    182 
    183 	return psbuf_get_reqid(cmp1) != psbuf_get_reqid(cmp2);
    184 }
    185 
    186 struct puffs_framebuf *
    187 psbuf_makeout()
    188 {
    189 	struct puffs_framebuf *pb;
    190 
    191 	pb = puffs_framebuf_make();
    192 	puffs_framebuf_seekset(pb, 4);
    193 	return pb;
    194 }
    195 
    196 void
    197 psbuf_recycleout(struct puffs_framebuf *pb)
    198 {
    199 
    200 	puffs_framebuf_recycle(pb);
    201 	puffs_framebuf_seekset(pb, 4);
    202 }
    203 
    204 void
    205 psbuf_put_1(struct puffs_framebuf *pb, uint8_t val)
    206 {
    207 	int rv;
    208 
    209 	rv = puffs_framebuf_putdata(pb, &val, 1);
    210 	CHECK(rv == 0);
    211 }
    212 
    213 void
    214 psbuf_put_2(struct puffs_framebuf *pb, uint16_t val)
    215 {
    216 	int rv;
    217 
    218 	HTOBE16(val);
    219 	rv = puffs_framebuf_putdata(pb, &val, 2);
    220 	CHECK(rv == 0);
    221 }
    222 
    223 void
    224 psbuf_put_4(struct puffs_framebuf *pb, uint32_t val)
    225 {
    226 	int rv;
    227 
    228 	HTOBE32(val);
    229 	rv = puffs_framebuf_putdata(pb, &val, 4);
    230 	CHECK(rv == 0);
    231 }
    232 
    233 void
    234 psbuf_put_8(struct puffs_framebuf *pb, uint64_t val)
    235 {
    236 	int rv;
    237 
    238 	HTOBE64(val);
    239 	rv = puffs_framebuf_putdata(pb, &val, 8);
    240 	CHECK(rv == 0);
    241 }
    242 
    243 void
    244 psbuf_put_data(struct puffs_framebuf *pb, const void *data, uint32_t dlen)
    245 {
    246 	int rv;
    247 
    248 	psbuf_put_4(pb, dlen);
    249 	rv = puffs_framebuf_putdata(pb, data, dlen);
    250 	CHECK(rv == 0);
    251 }
    252 
    253 void
    254 psbuf_put_str(struct puffs_framebuf *pb, const char *str)
    255 {
    256 
    257 	psbuf_put_data(pb, str, strlen(str));
    258 }
    259 
    260 void
    261 psbuf_put_vattr(struct puffs_framebuf *pb, const struct vattr *va,
    262 	const struct psshfs_ctx *pctx)
    263 {
    264 	uint32_t flags;
    265 	uint32_t theuid = -1, thegid = -1;
    266 	flags = 0;
    267 
    268 	if (va->va_size != (uint64_t)PUFFS_VNOVAL)
    269 		flags |= SSH_FILEXFER_ATTR_SIZE;
    270 	if (va->va_uid != (uid_t)PUFFS_VNOVAL) {
    271 		theuid = va->va_uid;
    272 		if (pctx->domangleuid && theuid == pctx->myuid)
    273 			theuid = pctx->mangleuid;
    274 		flags |= SSH_FILEXFER_ATTR_UIDGID;
    275 	}
    276 	if (va->va_gid != (gid_t)PUFFS_VNOVAL) {
    277 		thegid = va->va_gid;
    278 		if (pctx->domanglegid && thegid == pctx->mygid)
    279 			thegid = pctx->manglegid;
    280 		flags |= SSH_FILEXFER_ATTR_UIDGID;
    281 	}
    282 	if (va->va_mode != (mode_t)PUFFS_VNOVAL)
    283 		flags |= SSH_FILEXFER_ATTR_PERMISSIONS;
    284 
    285 	if (va->va_atime.tv_sec != PUFFS_VNOVAL)
    286 		flags |= SSH_FILEXFER_ATTR_ACCESSTIME;
    287 
    288 	psbuf_put_4(pb, flags);
    289 	if (flags & SSH_FILEXFER_ATTR_SIZE)
    290 		psbuf_put_8(pb, va->va_size);
    291 	if (flags & SSH_FILEXFER_ATTR_UIDGID) {
    292 		psbuf_put_4(pb, theuid);
    293 		psbuf_put_4(pb, thegid);
    294 	}
    295 	if (flags & SSH_FILEXFER_ATTR_PERMISSIONS)
    296 		psbuf_put_4(pb, va->va_mode);
    297 
    298 	/* XXX: this is totally wrong for protocol v3, see OpenSSH */
    299 	if (flags & SSH_FILEXFER_ATTR_ACCESSTIME) {
    300 		psbuf_put_4(pb, va->va_atime.tv_sec);
    301 		psbuf_put_4(pb, va->va_mtime.tv_sec);
    302 	}
    303 }
    304 
    305 #define ERETURN(rv) return ((rv) == -1 ? errno : 0)
    306 
    307 int
    308 psbuf_get_1(struct puffs_framebuf *pb, uint8_t *val)
    309 {
    310 
    311 	ERETURN(puffs_framebuf_getdata(pb, val, 1));
    312 }
    313 
    314 int
    315 psbuf_get_2(struct puffs_framebuf *pb, uint16_t *val)
    316 {
    317 	int rv;
    318 
    319 	rv = puffs_framebuf_getdata(pb, val, 2);
    320 	BE16TOH(*val);
    321 
    322 	ERETURN(rv);
    323 }
    324 
    325 int
    326 psbuf_get_4(struct puffs_framebuf *pb, uint32_t *val)
    327 {
    328 	int rv;
    329 
    330 	rv = puffs_framebuf_getdata(pb, val, 4);
    331 	BE32TOH(*val);
    332 
    333 	ERETURN(rv);
    334 }
    335 
    336 int
    337 psbuf_get_8(struct puffs_framebuf *pb, uint64_t *val)
    338 {
    339 	int rv;
    340 
    341 	rv = puffs_framebuf_getdata(pb, val, 8);
    342 	BE64TOH(*val);
    343 
    344 	ERETURN(rv);
    345 }
    346 
    347 int
    348 psbuf_get_str(struct puffs_framebuf *pb, char **strp, uint32_t *strlenp)
    349 {
    350 	char *str;
    351 	uint32_t len;
    352 
    353 	FAILRV(psbuf_get_4(pb, &len));
    354 
    355 	if (puffs_framebuf_remaining(pb) < len)
    356 		return EPROTO;
    357 
    358 	str = emalloc(len+1);
    359 	puffs_framebuf_getdata(pb, str, len);
    360 	str[len] = '\0';
    361 	*strp = str;
    362 
    363 	if (strlenp)
    364 		*strlenp = len;
    365 
    366 	return 0;
    367 }
    368 
    369 int
    370 psbuf_get_vattr(struct puffs_framebuf *pb, struct vattr *vap)
    371 {
    372 	uint32_t flags;
    373 	uint32_t val;
    374 
    375 	puffs_vattr_null(vap);
    376 
    377 	FAILRV(psbuf_get_4(pb, &flags));
    378 
    379 	if (flags & SSH_FILEXFER_ATTR_SIZE) {
    380 		FAILRV(psbuf_get_8(pb, &vap->va_size));
    381 		vap->va_bytes = vap->va_size;
    382 	}
    383 	if (flags & SSH_FILEXFER_ATTR_UIDGID) {
    384 		FAILRV(psbuf_get_4(pb, &vap->va_uid));
    385 		FAILRV(psbuf_get_4(pb, &vap->va_gid));
    386 	}
    387 	if (flags & SSH_FILEXFER_ATTR_PERMISSIONS) {
    388 		FAILRV(psbuf_get_4(pb, &vap->va_mode));
    389 		vap->va_type = puffs_mode2vt(vap->va_mode);
    390 	}
    391 	if (flags & SSH_FILEXFER_ATTR_ACCESSTIME) {
    392 		/*
    393 		 * XXX: this is utterly wrong if we want to speak
    394 		 * protocol version 3, but it seems like the
    395 		 * "internet standard" for doing this
    396 		 */
    397 		FAILRV(psbuf_get_4(pb, &val));
    398 		vap->va_atime.tv_sec = val;
    399 		FAILRV(psbuf_get_4(pb, &val));
    400 		vap->va_mtime.tv_sec = val;
    401 		/* make ctime the same as mtime */
    402 		vap->va_ctime.tv_sec = val;
    403 
    404 		vap->va_atime.tv_nsec = 0;
    405 		vap->va_ctime.tv_nsec = 0;
    406 		vap->va_mtime.tv_nsec = 0;
    407 	}
    408 
    409 	return 0;
    410 }
    411 
    412 /*
    413  * Buffer content helpers.  Caller frees all data.
    414  */
    415 
    416 /*
    417  * error mapping.. most are not expected for a file system, but
    418  * should help with diagnosing a possible error
    419  */
    420 static int emap[] = {
    421 	0,			/* OK			*/
    422 	0,			/* EOF			*/
    423 	ENOENT,			/* NO_SUCH_FILE		*/
    424 	EPERM,			/* PERMISSION_DENIED	*/
    425 	EIO,			/* FAILURE		*/
    426 	EBADMSG,		/* BAD_MESSAGE		*/
    427 	ENOTCONN,		/* NO_CONNECTION	*/
    428 	ECONNRESET,		/* CONNECTION_LOST	*/
    429 	EOPNOTSUPP,		/* OP_UNSUPPORTED	*/
    430 	EINVAL,			/* INVALID_HANDLE	*/
    431 	ENXIO,			/* NO_SUCH_PATH		*/
    432 	EEXIST,			/* FILE_ALREADY_EXISTS	*/
    433 	ENODEV			/* WRITE_PROTECT	*/
    434 };
    435 #define NERRORS ((int)(sizeof(emap) / sizeof(emap[0])))
    436 
    437 static int
    438 sftperr_to_errno(int error)
    439 {
    440 
    441 	if (!error)
    442 		return 0;
    443 
    444 	if (error >= NERRORS || error < 0)
    445 		return EPROTO;
    446 
    447 	return emap[error];
    448 }
    449 
    450 #define INVALRESPONSE EPROTO
    451 
    452 static int
    453 expectcode(struct puffs_framebuf *pb, int value)
    454 {
    455 	uint32_t error;
    456 	uint8_t type;
    457 
    458 	type = psbuf_get_type(pb);
    459 	if (type == value)
    460 		return 0;
    461 
    462 	if (type != SSH_FXP_STATUS)
    463 		return INVALRESPONSE;
    464 
    465 	FAILRV(psbuf_get_4(pb, &error));
    466 
    467 	return sftperr_to_errno(error);
    468 }
    469 
    470 #define CHECKCODE(pb,val)						\
    471 do {									\
    472 	int rv;								\
    473 	rv = expectcode(pb, val);					\
    474 	if (rv)								\
    475 		return rv;						\
    476 } while (/*CONSTCOND*/0)
    477 
    478 int
    479 psbuf_expect_status(struct puffs_framebuf *pb)
    480 {
    481 	uint32_t error;
    482 
    483 	if (psbuf_get_type(pb) != SSH_FXP_STATUS)
    484 		return INVALRESPONSE;
    485 
    486 	FAILRV(psbuf_get_4(pb, &error));
    487 
    488 	return sftperr_to_errno(error);
    489 }
    490 
    491 int
    492 psbuf_expect_handle(struct puffs_framebuf *pb, char **hand, uint32_t *handlen)
    493 {
    494 
    495 	CHECKCODE(pb, SSH_FXP_HANDLE);
    496 	FAILRV(psbuf_get_str(pb, hand, handlen));
    497 
    498 	return 0;
    499 }
    500 
    501 /* no memory allocation, direct copy */
    502 int
    503 psbuf_do_data(struct puffs_framebuf *pb, uint8_t *data, uint32_t *dlen)
    504 {
    505 	void *win;
    506 	size_t bufoff, winlen;
    507 	uint32_t len, dataoff;
    508 
    509 	if (psbuf_get_type(pb) != SSH_FXP_DATA) {
    510 		uint32_t val;
    511 
    512 		if (psbuf_get_type(pb) != SSH_FXP_STATUS)
    513 			return INVALRESPONSE;
    514 
    515 		if (psbuf_get_4(pb, &val) != 0)
    516 			return INVALRESPONSE;
    517 
    518 		if (val != SSH_FX_EOF)
    519 			return sftperr_to_errno(val);
    520 
    521 		*dlen = 0;
    522 		return 0;
    523 	}
    524 	if (psbuf_get_4(pb, &len) != 0)
    525 		return INVALRESPONSE;
    526 
    527 	if (*dlen < len)
    528 		return EINVAL;
    529 
    530 	*dlen = 0;
    531 
    532 	dataoff = 0;
    533 	while (dataoff < len) {
    534 		winlen = len-dataoff;
    535 		bufoff = puffs_framebuf_telloff(pb);
    536 		if (puffs_framebuf_getwindow(pb, bufoff,
    537 		    &win, &winlen) == -1)
    538 			return EINVAL;
    539 		if (winlen == 0)
    540 			break;
    541 
    542 		memcpy(data + dataoff, win, winlen);
    543 		dataoff += winlen;
    544 	}
    545 
    546 	*dlen = dataoff;
    547 
    548 	return 0;
    549 }
    550 
    551 int
    552 psbuf_expect_name(struct puffs_framebuf *pb, uint32_t *count)
    553 {
    554 
    555 	CHECKCODE(pb, SSH_FXP_NAME);
    556 	FAILRV(psbuf_get_4(pb, count));
    557 
    558 	return 0;
    559 }
    560 
    561 int
    562 psbuf_expect_attrs(struct puffs_framebuf *pb, struct vattr *vap)
    563 {
    564 
    565 	CHECKCODE(pb, SSH_FXP_ATTRS);
    566 	FAILRV(psbuf_get_vattr(pb, vap));
    567 
    568 	return 0;
    569 }
    570 
    571 /*
    572  * More helpers: larger-scale put functions
    573  */
    574 
    575 void
    576 psbuf_req_data(struct puffs_framebuf *pb, int type, uint32_t reqid,
    577 	const void *data, uint32_t dlen)
    578 {
    579 
    580 	psbuf_put_1(pb, type);
    581 	psbuf_put_4(pb, reqid);
    582 	psbuf_put_data(pb, data, dlen);
    583 }
    584 
    585 void
    586 psbuf_req_str(struct puffs_framebuf *pb, int type, uint32_t reqid,
    587 	const char *str)
    588 {
    589 
    590 	psbuf_req_data(pb, type, reqid, str, strlen(str));
    591 }
    592