/*      $OpenBSD: sshbuf-misc.c,v 1.18 2022/01/22 00:43:43 djm Exp $    */
/*
 * Copyright (c) 2011 Damien Miller
 *
 * 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 "includes.h"

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <stdlib.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <stdio.h>
#include <limits.h>
#include <string.h>
#include <resolv.h>
#include <ctype.h>
#include <unistd.h>

#include "ssherr.h"
#define SSHBUF_INTERNAL
#include "sshbuf.h"

void
sshbuf_dump_data(const void *s, size_t len, FILE *f)
{
        size_t i, j;
        const u_char *p = (const u_char *)s;

        for (i = 0; i < len; i += 16) {
                fprintf(f, "%.4zu: ", i);
                for (j = i; j < i + 16; j++) {
                        if (j < len)
                                fprintf(f, "%02x ", p[j]);
                        else
                                fprintf(f, "   ");
                }
                fprintf(f, " ");
                for (j = i; j < i + 16; j++) {
                        if (j < len) {
                                if  (isascii(p[j]) && isprint(p[j]))
                                        fprintf(f, "%c", p[j]);
                                else
                                        fprintf(f, ".");
                        }
                }
                fprintf(f, "\n");
        }
}

void
sshbuf_dump(const struct sshbuf *buf, FILE *f)
{
        fprintf(f, "buffer len = %zu\n", sshbuf_len(buf));
        sshbuf_dump_data(sshbuf_ptr(buf), sshbuf_len(buf), f);
}

char *
sshbuf_dtob16(struct sshbuf *buf)
{
        size_t i, j, len = sshbuf_len(buf);
        const u_char *p = sshbuf_ptr(buf);
        char *ret;
        const char hex[] = "0123456789abcdef";

        if (len == 0)
                return strdup("");
        if (SIZE_MAX / 2 <= len || (ret = malloc(len * 2 + 1)) == NULL)
                return NULL;
        for (i = j = 0; i < len; i++) {
                ret[j++] = hex[(p[i] >> 4) & 0xf];
                ret[j++] = hex[p[i] & 0xf];
        }
        ret[j] = '\0';
        return ret;
}

int
sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap)
{
        size_t i, slen = 0;
        char *s = NULL;
        int r;

        if (d == NULL || b64 == NULL || sshbuf_len(d) >= SIZE_MAX / 2)
                return SSH_ERR_INVALID_ARGUMENT;
        if (sshbuf_len(d) == 0)
                return 0;
        slen = ((sshbuf_len(d) + 2) / 3) * 4 + 1;
        if ((s = malloc(slen)) == NULL)
                return SSH_ERR_ALLOC_FAIL;
        if (b64_ntop(sshbuf_ptr(d), sshbuf_len(d), s, slen) == -1) {
                r = SSH_ERR_INTERNAL_ERROR;
                goto fail;
        }
        if (wrap) {
                for (i = 0; s[i] != '\0'; i++) {
                        if ((r = sshbuf_put_u8(b64, s[i])) != 0)
                                goto fail;
                        if (i % 70 == 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)
                                goto fail;
                }
                if ((i - 1) % 70 != 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)
                        goto fail;
        } else {
                if ((r = sshbuf_put(b64, s, strlen(s))) != 0)
                        goto fail;
        }
        /* Success */
        r = 0;
 fail:
        freezero(s, slen);
        return r;
}

char *
sshbuf_dtob64_string(const struct sshbuf *buf, int wrap)
{
        struct sshbuf *tmp;
        char *ret;

        if ((tmp = sshbuf_new()) == NULL)
                return NULL;
        if (sshbuf_dtob64(buf, tmp, wrap) != 0) {
                sshbuf_free(tmp);
                return NULL;
        }
        ret = sshbuf_dup_string(tmp);
        sshbuf_free(tmp);
        return ret;
}

int
sshbuf_b64tod(struct sshbuf *buf, const char *b64)
{
        size_t plen = strlen(b64);
        int nlen, r;
        u_char *p;

        if (plen == 0)
                return 0;
        if ((p = malloc(plen)) == NULL)
                return SSH_ERR_ALLOC_FAIL;
        if ((nlen = b64_pton(b64, p, plen)) < 0) {
                freezero(p, plen);
                return SSH_ERR_INVALID_FORMAT;
        }
        if ((r = sshbuf_put(buf, p, nlen)) < 0) {
                freezero(p, plen);
                return r;
        }
        freezero(p, plen);
        return 0;
}

int
sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap)
{
        int r = SSH_ERR_INTERNAL_ERROR;
        u_char *p;
        struct sshbuf *b = NULL;
        size_t i, l;

        if ((b = sshbuf_new()) == NULL)
                return SSH_ERR_ALLOC_FAIL;
        /* Encode using regular base64; we'll transform it once done */
        if ((r = sshbuf_dtob64(d, b, wrap)) != 0)
                goto out;
        /* remove padding from end of encoded string*/
        for (;;) {
                l = sshbuf_len(b);
                if (l <= 1 || sshbuf_ptr(b) == NULL) {
                        r = SSH_ERR_INTERNAL_ERROR;
                        goto out;
                }
                if (sshbuf_ptr(b)[l - 1] != '=')
                        break;
                if ((r = sshbuf_consume_end(b, 1)) != 0)
                        goto out;
        }
        /* Replace characters with rfc4648 equivalents */
        l = sshbuf_len(b);
        if ((p = sshbuf_mutable_ptr(b)) == NULL) {
                r = SSH_ERR_INTERNAL_ERROR;
                goto out;
        }
        for (i = 0; i < l; i++) {
                if (p[i] == '+')
                        p[i] = '-';
                else if (p[i] == '/')
                        p[i] = '_';
        }
        r = sshbuf_putb(b64, b);
 out:
        sshbuf_free(b);
        return r;
}

char *
sshbuf_dup_string(struct sshbuf *buf)
{
        const u_char *p = NULL, *s = sshbuf_ptr(buf);
        size_t l = sshbuf_len(buf);
        char *r;

        if (s == NULL || l > SIZE_MAX)
                return NULL;
        /* accept a nul only as the last character in the buffer */
        if (l > 0 && (p = memchr(s, '\0', l)) != NULL) {
                if (p != s + l - 1)
                        return NULL;
                l--; /* the nul is put back below */
        }
        if ((r = malloc(l + 1)) == NULL)
                return NULL;
        if (l > 0)
                memcpy(r, s, l);
        r[l] = '\0';
        return r;
}

int
sshbuf_cmp(const struct sshbuf *b, size_t offset,
    const void *s, size_t len)
{
        if (sshbuf_ptr(b) == NULL)
                return SSH_ERR_INTERNAL_ERROR;
        if (offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
                return SSH_ERR_INVALID_ARGUMENT;
        if (offset + len > sshbuf_len(b))
                return SSH_ERR_MESSAGE_INCOMPLETE;
        if (timingsafe_bcmp(sshbuf_ptr(b) + offset, s, len) != 0)
                return SSH_ERR_INVALID_FORMAT;
        return 0;
}

int
sshbuf_find(const struct sshbuf *b, size_t start_offset,
    const void *s, size_t len, size_t *offsetp)
{
        void *p;

        if (offsetp != NULL)
                *offsetp = 0;
        if (sshbuf_ptr(b) == NULL)
                return SSH_ERR_INTERNAL_ERROR;
        if (start_offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
                return SSH_ERR_INVALID_ARGUMENT;
        if (start_offset > sshbuf_len(b) || start_offset + len > sshbuf_len(b))
                return SSH_ERR_MESSAGE_INCOMPLETE;
        if ((p = memmem(sshbuf_ptr(b) + start_offset,
            sshbuf_len(b) - start_offset, s, len)) == NULL)
                return SSH_ERR_INVALID_FORMAT;
        if (offsetp != NULL)
                *offsetp = (const u_char *)p - sshbuf_ptr(b);
        return 0;
}

int
sshbuf_read(int fd, struct sshbuf *buf, size_t maxlen, size_t *rlen)
{
        int r, oerrno;
        size_t adjust;
        ssize_t rr;
        u_char *d;

        if (rlen != NULL)
                *rlen = 0;
        if ((r = sshbuf_reserve(buf, maxlen, &d)) != 0)
                return r;
        rr = read(fd, d, maxlen);
        oerrno = errno;

        /* Adjust the buffer to include only what was actually read */
        if ((adjust = maxlen - (rr > 0 ? rr : 0)) != 0) {
                if ((r = sshbuf_consume_end(buf, adjust)) != 0) {
                        /* avoid returning uninitialised data to caller */
                        memset(d + rr, '\0', adjust);
                        return SSH_ERR_INTERNAL_ERROR; /* shouldn't happen */
                }
        }
        if (rr < 0) {
                errno = oerrno;
                return SSH_ERR_SYSTEM_ERROR;
        } else if (rr == 0) {
                errno = EPIPE;
                return SSH_ERR_SYSTEM_ERROR;
        }
        /* success */
        if (rlen != NULL)
                *rlen = (size_t)rr;
        return 0;
}