1 /*	$OpenBSD: sshbuf-io.c,v 1.2 2020/01/25 23:28:06 djm Exp $ */
2 /*
3  * Copyright (c) 2011 Damien Miller
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include "includes.h"
19 
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <unistd.h>
26 #include <string.h>
27 
28 #include "ssherr.h"
29 #include "sshbuf.h"
30 #include "atomicio.h"
31 
32 /* Load a file from a fd into a buffer */
33 int
sshbuf_load_fd(int fd,struct sshbuf ** blobp)34 sshbuf_load_fd(int fd, struct sshbuf **blobp)
35 {
36 	u_char buf[4096];
37 	size_t len;
38 	struct stat st;
39 	int r;
40 	struct sshbuf *blob;
41 
42 	*blobp = NULL;
43 
44 	if (fstat(fd, &st) == -1)
45 		return SSH_ERR_SYSTEM_ERROR;
46 	if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
47 	    st.st_size > SSHBUF_SIZE_MAX)
48 		return SSH_ERR_INVALID_FORMAT;
49 	if ((blob = sshbuf_new()) == NULL)
50 		return SSH_ERR_ALLOC_FAIL;
51 	for (;;) {
52 		if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) {
53 			if (errno == EPIPE)
54 				break;
55 			r = SSH_ERR_SYSTEM_ERROR;
56 			goto out;
57 		}
58 		if ((r = sshbuf_put(blob, buf, len)) != 0)
59 			goto out;
60 		if (sshbuf_len(blob) > SSHBUF_SIZE_MAX) {
61 			r = SSH_ERR_INVALID_FORMAT;
62 			goto out;
63 		}
64 	}
65 	if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 &&
66 	    st.st_size != (off_t)sshbuf_len(blob)) {
67 		r = SSH_ERR_FILE_CHANGED;
68 		goto out;
69 	}
70 	/* success */
71 	*blobp = blob;
72 	blob = NULL; /* transferred */
73 	r = 0;
74  out:
75 	explicit_bzero(buf, sizeof(buf));
76 	sshbuf_free(blob);
77 	return r;
78 }
79 
80 int
sshbuf_load_file(const char * path,struct sshbuf ** bufp)81 sshbuf_load_file(const char *path, struct sshbuf **bufp)
82 {
83 	int r, fd, oerrno;
84 
85 	*bufp = NULL;
86 	if ((fd = open(path, O_RDONLY)) == -1)
87 		return SSH_ERR_SYSTEM_ERROR;
88 	if ((r = sshbuf_load_fd(fd, bufp)) != 0)
89 		goto out;
90 	/* success */
91 	r = 0;
92  out:
93 	oerrno = errno;
94 	close(fd);
95 	if (r != 0)
96 		errno = oerrno;
97 	return r;
98 }
99 
100 int
sshbuf_write_file(const char * path,struct sshbuf * buf)101 sshbuf_write_file(const char *path, struct sshbuf *buf)
102 {
103 	int fd, oerrno;
104 
105 	if ((fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644)) == -1)
106 		return SSH_ERR_SYSTEM_ERROR;
107 	if (atomicio(vwrite, fd, sshbuf_mutable_ptr(buf),
108 	    sshbuf_len(buf)) != sshbuf_len(buf) || close(fd) != 0) {
109 		oerrno = errno;
110 		close(fd);
111 		unlink(path);
112 		errno = oerrno;
113 		return SSH_ERR_SYSTEM_ERROR;
114 	}
115 	return 0;
116 }
117 
118