/* $OpenBSD: sshbuf-getput-basic.c,v 1.13 2022/05/25 06:03:44 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" __RCSID("$NetBSD: sshbuf-getput-basic.c,v 1.8.6.1 2023/12/25 12:31:09 martin Exp $"); #include #include #include #include #include #include #include "ssherr.h" #define SSHBUF_INTERNAL #include "sshbuf.h" int sshbuf_get(struct sshbuf *buf, void *v, size_t len) { const u_char *p = sshbuf_ptr(buf); int r; if ((r = sshbuf_consume(buf, len)) < 0) return r; if (v != NULL && len != 0) memcpy(v, p, len); return 0; } int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp) { const u_char *p = sshbuf_ptr(buf); int r; if ((r = sshbuf_consume(buf, 8)) < 0) return r; if (valp != NULL) *valp = PEEK_U64(p); return 0; } int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp) { const u_char *p = sshbuf_ptr(buf); int r; if ((r = sshbuf_consume(buf, 4)) < 0) return r; if (valp != NULL) *valp = PEEK_U32(p); return 0; } int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp) { const u_char *p = sshbuf_ptr(buf); int r; if ((r = sshbuf_consume(buf, 2)) < 0) return r; if (valp != NULL) *valp = PEEK_U16(p); return 0; } int sshbuf_get_u8(struct sshbuf *buf, u_char *valp) { const u_char *p = sshbuf_ptr(buf); int r; if ((r = sshbuf_consume(buf, 1)) < 0) return r; if (valp != NULL) *valp = (u_int8_t)*p; return 0; } static int check_offset(const struct sshbuf *buf, int wr, size_t offset, size_t len) { if (sshbuf_ptr(buf) == NULL) /* calls sshbuf_check_sanity() */ return SSH_ERR_INTERNAL_ERROR; if (offset >= SIZE_MAX - len) return SSH_ERR_INVALID_ARGUMENT; if (offset + len > sshbuf_len(buf)) { return wr ? SSH_ERR_NO_BUFFER_SPACE : SSH_ERR_MESSAGE_INCOMPLETE; } return 0; } static int check_roffset(const struct sshbuf *buf, size_t offset, size_t len, const u_char **p) { int r; *p = NULL; if ((r = check_offset(buf, 0, offset, len)) != 0) return r; *p = sshbuf_ptr(buf) + offset; return 0; } int sshbuf_peek_u64(const struct sshbuf *buf, size_t offset, u_int64_t *valp) { const u_char *p = NULL; int r; if (valp != NULL) *valp = 0; if ((r = check_roffset(buf, offset, 8, &p)) != 0) return r; if (valp != NULL) *valp = PEEK_U64(p); return 0; } int sshbuf_peek_u32(const struct sshbuf *buf, size_t offset, u_int32_t *valp) { const u_char *p = NULL; int r; if (valp != NULL) *valp = 0; if ((r = check_roffset(buf, offset, 4, &p)) != 0) return r; if (valp != NULL) *valp = PEEK_U32(p); return 0; } int sshbuf_peek_u16(const struct sshbuf *buf, size_t offset, u_int16_t *valp) { const u_char *p = NULL; int r; if (valp != NULL) *valp = 0; if ((r = check_roffset(buf, offset, 2, &p)) != 0) return r; if (valp != NULL) *valp = PEEK_U16(p); return 0; } int sshbuf_peek_u8(const struct sshbuf *buf, size_t offset, u_char *valp) { const u_char *p = NULL; int r; if (valp != NULL) *valp = 0; if ((r = check_roffset(buf, offset, 1, &p)) != 0) return r; if (valp != NULL) *valp = *p; return 0; } int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp) { const u_char *val; size_t len; int r; if (valp != NULL) *valp = NULL; if (lenp != NULL) *lenp = 0; if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0) return r; if (valp != NULL) { if ((*valp = malloc(len + 1)) == NULL) { SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); return SSH_ERR_ALLOC_FAIL; } if (len != 0) memcpy(*valp, val, len); (*valp)[len] = '\0'; } if (lenp != NULL) *lenp = len; return 0; } int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp) { size_t len; const u_char *p; int r; if (valp != NULL) *valp = NULL; if (lenp != NULL) *lenp = 0; if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0) return r; if (valp != NULL) *valp = p; if (lenp != NULL) *lenp = len; if (sshbuf_consume(buf, len + 4) != 0) { /* Shouldn't happen */ SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); SSHBUF_ABORT(); return SSH_ERR_INTERNAL_ERROR; } return 0; } int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp, size_t *lenp) { u_int32_t len; const u_char *p = sshbuf_ptr(buf); if (valp != NULL) *valp = NULL; if (lenp != NULL) *lenp = 0; if (sshbuf_len(buf) < 4) { SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); return SSH_ERR_MESSAGE_INCOMPLETE; } len = PEEK_U32(p); if (len > SSHBUF_SIZE_MAX - 4) { SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE")); return SSH_ERR_STRING_TOO_LARGE; } if (sshbuf_len(buf) - 4 < len) { SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE")); return SSH_ERR_MESSAGE_INCOMPLETE; } if (valp != NULL) *valp = p + 4; if (lenp != NULL) *lenp = len; return 0; } int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp) { size_t len; const u_char *p, *z; int r; if (valp != NULL) *valp = NULL; if (lenp != NULL) *lenp = 0; if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) return r; /* Allow a \0 only at the end of the string */ if (len > 0 && (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) { SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT")); return SSH_ERR_INVALID_FORMAT; } if ((r = sshbuf_skip_string(buf)) != 0) return -1; if (valp != NULL) { if ((*valp = malloc(len + 1)) == NULL) { SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL")); return SSH_ERR_ALLOC_FAIL; } if (len != 0) memcpy(*valp, p, len); (*valp)[len] = '\0'; } if (lenp != NULL) *lenp = (size_t)len; return 0; } int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v) { u_int32_t len; u_char *p; int r; /* * Use sshbuf_peek_string_direct() to figure out if there is * a complete string in 'buf' and copy the string directly * into 'v'. */ if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 || (r = sshbuf_get_u32(buf, &len)) != 0 || (r = sshbuf_reserve(v, len, &p)) != 0 || (r = sshbuf_get(buf, p, len)) != 0) return r; return 0; } int sshbuf_put(struct sshbuf *buf, const void *v, size_t len) { u_char *p; int r; if ((r = sshbuf_reserve(buf, len, &p)) < 0) return r; if (len != 0) memcpy(p, v, len); return 0; } int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v) { if (v == NULL) return 0; return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v)); } int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...) { va_list ap; int r; va_start(ap, fmt); r = sshbuf_putfv(buf, fmt, ap); va_end(ap); return r; } int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap) { va_list ap2; int r, len; u_char *p; va_copy(ap2, ap); if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } if (len == 0) { r = 0; goto out; /* Nothing to do */ } va_end(ap2); va_copy(ap2, ap); if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0) goto out; if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) { r = SSH_ERR_INTERNAL_ERROR; goto out; /* Shouldn't happen */ } /* Consume terminating \0 */ if ((r = sshbuf_consume_end(buf, 1)) != 0) goto out; r = 0; out: va_end(ap2); return r; } int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val) { u_char *p; int r; if ((r = sshbuf_reserve(buf, 8, &p)) < 0) return r; POKE_U64(p, val); return 0; } int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val) { u_char *p; int r; if ((r = sshbuf_reserve(buf, 4, &p)) < 0) return r; POKE_U32(p, val); return 0; } int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val) { u_char *p; int r; if ((r = sshbuf_reserve(buf, 2, &p)) < 0) return r; POKE_U16(p, val); return 0; } int sshbuf_put_u8(struct sshbuf *buf, u_char val) { u_char *p; int r; if ((r = sshbuf_reserve(buf, 1, &p)) < 0) return r; p[0] = val; return 0; } static int check_woffset(struct sshbuf *buf, size_t offset, size_t len, u_char **p) { int r; *p = NULL; if ((r = check_offset(buf, 1, offset, len)) != 0) return r; if (sshbuf_mutable_ptr(buf) == NULL) return SSH_ERR_BUFFER_READ_ONLY; *p = sshbuf_mutable_ptr(buf) + offset; return 0; } int sshbuf_poke_u64(struct sshbuf *buf, size_t offset, u_int64_t val) { u_char *p = NULL; int r; if ((r = check_woffset(buf, offset, 8, &p)) != 0) return r; POKE_U64(p, val); return 0; } int sshbuf_poke_u32(struct sshbuf *buf, size_t offset, u_int32_t val) { u_char *p = NULL; int r; if ((r = check_woffset(buf, offset, 4, &p)) != 0) return r; POKE_U32(p, val); return 0; } int sshbuf_poke_u16(struct sshbuf *buf, size_t offset, u_int16_t val) { u_char *p = NULL; int r; if ((r = check_woffset(buf, offset, 2, &p)) != 0) return r; POKE_U16(p, val); return 0; } int sshbuf_poke_u8(struct sshbuf *buf, size_t offset, u_char val) { u_char *p = NULL; int r; if ((r = check_woffset(buf, offset, 1, &p)) != 0) return r; *p = val; return 0; } int sshbuf_poke(struct sshbuf *buf, size_t offset, void *v, size_t len) { u_char *p = NULL; int r; if ((r = check_woffset(buf, offset, len, &p)) != 0) return r; memcpy(p, v, len); return 0; } int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len) { u_char *d; int r; if (len > SSHBUF_SIZE_MAX - 4) { SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); return SSH_ERR_NO_BUFFER_SPACE; } if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0) return r; POKE_U32(d, len); if (len != 0) memcpy(d + 4, v, len); return 0; } int sshbuf_put_cstring(struct sshbuf *buf, const char *v) { return sshbuf_put_string(buf, __UNCONST(v), v == NULL ? 0 : strlen(v)); } int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v) { if (v == NULL) return sshbuf_put_string(buf, NULL, 0); return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v)); } int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp) { const u_char *p; size_t len; struct sshbuf *ret; int r; if (buf == NULL || bufp == NULL) return SSH_ERR_INVALID_ARGUMENT; *bufp = NULL; if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0) return r; if ((ret = sshbuf_from(p, len)) == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = sshbuf_consume(buf, len + 4)) != 0 || /* Shouldn't happen */ (r = sshbuf_set_parent(ret, buf)) != 0) { sshbuf_free(ret); return r; } *bufp = ret; return 0; } int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len) { u_char *d; const u_char *s = (const u_char *)v; int r, prepend; if (len > SSHBUF_SIZE_MAX - 5) { SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE")); return SSH_ERR_NO_BUFFER_SPACE; } /* Skip leading zero bytes */ for (; len > 0 && *s == 0; len--, s++) ; /* * If most significant bit is set then prepend a zero byte to * avoid interpretation as a negative number. */ prepend = len > 0 && (s[0] & 0x80) != 0; if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0) return r; POKE_U32(d, len + prepend); if (prepend) d[4] = 0; if (len != 0) memcpy(d + 4 + prepend, s, len); return 0; } int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp) { const u_char *d; size_t len, olen; int r; if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0) return r; len = olen; /* Refuse negative (MSB set) bignums */ if ((len != 0 && (*d & 0x80) != 0)) return SSH_ERR_BIGNUM_IS_NEGATIVE; /* Refuse overlong bignums, allow prepended \0 to avoid MSB set */ if (len > SSHBUF_MAX_BIGNUM + 1 || (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0)) return SSH_ERR_BIGNUM_TOO_LARGE; /* Trim leading zeros */ while (len > 0 && *d == 0x00) { d++; len--; } if (valp != NULL) *valp = d; if (lenp != NULL) *lenp = len; if (sshbuf_consume(buf, olen + 4) != 0) { /* Shouldn't happen */ SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR")); SSHBUF_ABORT(); return SSH_ERR_INTERNAL_ERROR; } return 0; }