diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/evp/bio_ok.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/evp/bio_ok.c | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/evp/bio_ok.c b/openssl-1.1.0h/crypto/evp/bio_ok.c new file mode 100644 index 0000000..b156e62 --- /dev/null +++ b/openssl-1.1.0h/crypto/evp/bio_ok.c @@ -0,0 +1,605 @@ +/* + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +/*- + From: Arne Ansper <arne@cyber.ee> + + Why BIO_f_reliable? + + I wrote function which took BIO* as argument, read data from it + and processed it. Then I wanted to store the input file in + encrypted form. OK I pushed BIO_f_cipher to the BIO stack + and everything was OK. BUT if user types wrong password + BIO_f_cipher outputs only garbage and my function crashes. Yes + I can and I should fix my function, but BIO_f_cipher is + easy way to add encryption support to many existing applications + and it's hard to debug and fix them all. + + So I wanted another BIO which would catch the incorrect passwords and + file damages which cause garbage on BIO_f_cipher's output. + + The easy way is to push the BIO_f_md and save the checksum at + the end of the file. However there are several problems with this + approach: + + 1) you must somehow separate checksum from actual data. + 2) you need lot's of memory when reading the file, because you + must read to the end of the file and verify the checksum before + letting the application to read the data. + + BIO_f_reliable tries to solve both problems, so that you can + read and write arbitrary long streams using only fixed amount + of memory. + + BIO_f_reliable splits data stream into blocks. Each block is prefixed + with it's length and suffixed with it's digest. So you need only + several Kbytes of memory to buffer single block before verifying + it's digest. + + BIO_f_reliable goes further and adds several important capabilities: + + 1) the digest of the block is computed over the whole stream + -- so nobody can rearrange the blocks or remove or replace them. + + 2) to detect invalid passwords right at the start BIO_f_reliable + adds special prefix to the stream. In order to avoid known plain-text + attacks this prefix is generated as follows: + + *) digest is initialized with random seed instead of + standardized one. + *) same seed is written to output + *) well-known text is then hashed and the output + of the digest is also written to output. + + reader can now read the seed from stream, hash the same string + and then compare the digest output. + + Bad things: BIO_f_reliable knows what's going on in EVP_Digest. I + initially wrote and tested this code on x86 machine and wrote the + digests out in machine-dependent order :( There are people using + this code and I cannot change this easily without making existing + data files unreadable. + +*/ + +#include <stdio.h> +#include <errno.h> +#include <assert.h> +#include "internal/cryptlib.h" +#include <openssl/buffer.h> +#include "internal/bio.h" +#include <openssl/evp.h> +#include <openssl/rand.h> +#include "internal/evp_int.h" + +static int ok_write(BIO *h, const char *buf, int num); +static int ok_read(BIO *h, char *buf, int size); +static long ok_ctrl(BIO *h, int cmd, long arg1, void *arg2); +static int ok_new(BIO *h); +static int ok_free(BIO *data); +static long ok_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp); + +static __owur int sig_out(BIO *b); +static __owur int sig_in(BIO *b); +static __owur int block_out(BIO *b); +static __owur int block_in(BIO *b); +#define OK_BLOCK_SIZE (1024*4) +#define OK_BLOCK_BLOCK 4 +#define IOBS (OK_BLOCK_SIZE+ OK_BLOCK_BLOCK+ 3*EVP_MAX_MD_SIZE) +#define WELLKNOWN "The quick brown fox jumped over the lazy dog's back." + +typedef struct ok_struct { + size_t buf_len; + size_t buf_off; + size_t buf_len_save; + size_t buf_off_save; + int cont; /* <= 0 when finished */ + int finished; + EVP_MD_CTX *md; + int blockout; /* output block is ready */ + int sigio; /* must process signature */ + unsigned char buf[IOBS]; +} BIO_OK_CTX; + +static const BIO_METHOD methods_ok = { + BIO_TYPE_CIPHER, + "reliable", + ok_write, + ok_read, + NULL, /* ok_puts, */ + NULL, /* ok_gets, */ + ok_ctrl, + ok_new, + ok_free, + ok_callback_ctrl, +}; + +const BIO_METHOD *BIO_f_reliable(void) +{ + return (&methods_ok); +} + +static int ok_new(BIO *bi) +{ + BIO_OK_CTX *ctx; + + ctx = OPENSSL_zalloc(sizeof(*ctx)); + if (ctx == NULL) + return 0; + + ctx->cont = 1; + ctx->sigio = 1; + ctx->md = EVP_MD_CTX_new(); + if (ctx->md == NULL) { + OPENSSL_free(ctx); + return 0; + } + BIO_set_init(bi, 0); + BIO_set_data(bi, ctx); + + return 1; +} + +static int ok_free(BIO *a) +{ + BIO_OK_CTX *ctx; + + if (a == NULL) + return 0; + + ctx = BIO_get_data(a); + + EVP_MD_CTX_free(ctx->md); + OPENSSL_clear_free(ctx, sizeof(BIO_OK_CTX)); + BIO_set_data(a, NULL); + BIO_set_init(a, 0); + + return 1; +} + +static int ok_read(BIO *b, char *out, int outl) +{ + int ret = 0, i, n; + BIO_OK_CTX *ctx; + BIO *next; + + if (out == NULL) + return 0; + + ctx = BIO_get_data(b); + next = BIO_next(b); + + if ((ctx == NULL) || (next == NULL) || (BIO_get_init(b) == 0)) + return 0; + + while (outl > 0) { + + /* copy clean bytes to output buffer */ + if (ctx->blockout) { + i = ctx->buf_len - ctx->buf_off; + if (i > outl) + i = outl; + memcpy(out, &(ctx->buf[ctx->buf_off]), i); + ret += i; + out += i; + outl -= i; + ctx->buf_off += i; + + /* all clean bytes are out */ + if (ctx->buf_len == ctx->buf_off) { + ctx->buf_off = 0; + + /* + * copy start of the next block into proper place + */ + if (ctx->buf_len_save - ctx->buf_off_save > 0) { + ctx->buf_len = ctx->buf_len_save - ctx->buf_off_save; + memmove(ctx->buf, &(ctx->buf[ctx->buf_off_save]), + ctx->buf_len); + } else { + ctx->buf_len = 0; + } + ctx->blockout = 0; + } + } + + /* output buffer full -- cancel */ + if (outl == 0) + break; + + /* no clean bytes in buffer -- fill it */ + n = IOBS - ctx->buf_len; + i = BIO_read(next, &(ctx->buf[ctx->buf_len]), n); + + if (i <= 0) + break; /* nothing new */ + + ctx->buf_len += i; + + /* no signature yet -- check if we got one */ + if (ctx->sigio == 1) { + if (!sig_in(b)) { + BIO_clear_retry_flags(b); + return 0; + } + } + + /* signature ok -- check if we got block */ + if (ctx->sigio == 0) { + if (!block_in(b)) { + BIO_clear_retry_flags(b); + return 0; + } + } + + /* invalid block -- cancel */ + if (ctx->cont <= 0) + break; + + } + + BIO_clear_retry_flags(b); + BIO_copy_next_retry(b); + return ret; +} + +static int ok_write(BIO *b, const char *in, int inl) +{ + int ret = 0, n, i; + BIO_OK_CTX *ctx; + BIO *next; + + if (inl <= 0) + return inl; + + ctx = BIO_get_data(b); + next = BIO_next(b); + ret = inl; + + if ((ctx == NULL) || (next == NULL) || (BIO_get_init(b) == 0)) + return (0); + + if (ctx->sigio && !sig_out(b)) + return 0; + + do { + BIO_clear_retry_flags(b); + n = ctx->buf_len - ctx->buf_off; + while (ctx->blockout && n > 0) { + i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n); + if (i <= 0) { + BIO_copy_next_retry(b); + if (!BIO_should_retry(b)) + ctx->cont = 0; + return (i); + } + ctx->buf_off += i; + n -= i; + } + + /* at this point all pending data has been written */ + ctx->blockout = 0; + if (ctx->buf_len == ctx->buf_off) { + ctx->buf_len = OK_BLOCK_BLOCK; + ctx->buf_off = 0; + } + + if ((in == NULL) || (inl <= 0)) + return (0); + + n = (inl + ctx->buf_len > OK_BLOCK_SIZE + OK_BLOCK_BLOCK) ? + (int)(OK_BLOCK_SIZE + OK_BLOCK_BLOCK - ctx->buf_len) : inl; + + memcpy(&ctx->buf[ctx->buf_len], in, n); + ctx->buf_len += n; + inl -= n; + in += n; + + if (ctx->buf_len >= OK_BLOCK_SIZE + OK_BLOCK_BLOCK) { + if (!block_out(b)) { + BIO_clear_retry_flags(b); + return 0; + } + } + } while (inl > 0); + + BIO_clear_retry_flags(b); + BIO_copy_next_retry(b); + return (ret); +} + +static long ok_ctrl(BIO *b, int cmd, long num, void *ptr) +{ + BIO_OK_CTX *ctx; + EVP_MD *md; + const EVP_MD **ppmd; + long ret = 1; + int i; + BIO *next; + + ctx = BIO_get_data(b); + next = BIO_next(b); + + switch (cmd) { + case BIO_CTRL_RESET: + ctx->buf_len = 0; + ctx->buf_off = 0; + ctx->buf_len_save = 0; + ctx->buf_off_save = 0; + ctx->cont = 1; + ctx->finished = 0; + ctx->blockout = 0; + ctx->sigio = 1; + ret = BIO_ctrl(next, cmd, num, ptr); + break; + case BIO_CTRL_EOF: /* More to read */ + if (ctx->cont <= 0) + ret = 1; + else + ret = BIO_ctrl(next, cmd, num, ptr); + break; + case BIO_CTRL_PENDING: /* More to read in buffer */ + case BIO_CTRL_WPENDING: /* More to read in buffer */ + ret = ctx->blockout ? ctx->buf_len - ctx->buf_off : 0; + if (ret <= 0) + ret = BIO_ctrl(next, cmd, num, ptr); + break; + case BIO_CTRL_FLUSH: + /* do a final write */ + if (ctx->blockout == 0) + if (!block_out(b)) + return 0; + + while (ctx->blockout) { + i = ok_write(b, NULL, 0); + if (i < 0) { + ret = i; + break; + } + } + + ctx->finished = 1; + ctx->buf_off = ctx->buf_len = 0; + ctx->cont = (int)ret; + + /* Finally flush the underlying BIO */ + ret = BIO_ctrl(next, cmd, num, ptr); + break; + case BIO_C_DO_STATE_MACHINE: + BIO_clear_retry_flags(b); + ret = BIO_ctrl(next, cmd, num, ptr); + BIO_copy_next_retry(b); + break; + case BIO_CTRL_INFO: + ret = (long)ctx->cont; + break; + case BIO_C_SET_MD: + md = ptr; + if (!EVP_DigestInit_ex(ctx->md, md, NULL)) + return 0; + BIO_set_init(b, 1); + break; + case BIO_C_GET_MD: + if (BIO_get_init(b)) { + ppmd = ptr; + *ppmd = EVP_MD_CTX_md(ctx->md); + } else + ret = 0; + break; + default: + ret = BIO_ctrl(next, cmd, num, ptr); + break; + } + return ret; +} + +static long ok_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp) +{ + long ret = 1; + BIO *next; + + next = BIO_next(b); + + if (next == NULL) + return 0; + + switch (cmd) { + default: + ret = BIO_callback_ctrl(next, cmd, fp); + break; + } + + return ret; +} + +static void longswap(void *_ptr, size_t len) +{ + const union { + long one; + char little; + } is_endian = { + 1 + }; + + if (is_endian.little) { + size_t i; + unsigned char *p = _ptr, c; + + for (i = 0; i < len; i += 4) { + c = p[0], p[0] = p[3], p[3] = c; + c = p[1], p[1] = p[2], p[2] = c; + } + } +} + +static int sig_out(BIO *b) +{ + BIO_OK_CTX *ctx; + EVP_MD_CTX *md; + const EVP_MD *digest; + int md_size; + void *md_data; + + ctx = BIO_get_data(b); + md = ctx->md; + digest = EVP_MD_CTX_md(md); + md_size = EVP_MD_size(digest); + md_data = EVP_MD_CTX_md_data(md); + + if (ctx->buf_len + 2 * md_size > OK_BLOCK_SIZE) + return 1; + + if (!EVP_DigestInit_ex(md, digest, NULL)) + goto berr; + /* + * FIXME: there's absolutely no guarantee this makes any sense at all, + * particularly now EVP_MD_CTX has been restructured. + */ + if (RAND_bytes(md_data, md_size) <= 0) + goto berr; + memcpy(&(ctx->buf[ctx->buf_len]), md_data, md_size); + longswap(&(ctx->buf[ctx->buf_len]), md_size); + ctx->buf_len += md_size; + + if (!EVP_DigestUpdate(md, WELLKNOWN, strlen(WELLKNOWN))) + goto berr; + if (!EVP_DigestFinal_ex(md, &(ctx->buf[ctx->buf_len]), NULL)) + goto berr; + ctx->buf_len += md_size; + ctx->blockout = 1; + ctx->sigio = 0; + return 1; + berr: + BIO_clear_retry_flags(b); + return 0; +} + +static int sig_in(BIO *b) +{ + BIO_OK_CTX *ctx; + EVP_MD_CTX *md; + unsigned char tmp[EVP_MAX_MD_SIZE]; + int ret = 0; + const EVP_MD *digest; + int md_size; + void *md_data; + + ctx = BIO_get_data(b); + md = ctx->md; + digest = EVP_MD_CTX_md(md); + md_size = EVP_MD_size(digest); + md_data = EVP_MD_CTX_md_data(md); + + if ((int)(ctx->buf_len - ctx->buf_off) < 2 * md_size) + return 1; + + if (!EVP_DigestInit_ex(md, digest, NULL)) + goto berr; + memcpy(md_data, &(ctx->buf[ctx->buf_off]), md_size); + longswap(md_data, md_size); + ctx->buf_off += md_size; + + if (!EVP_DigestUpdate(md, WELLKNOWN, strlen(WELLKNOWN))) + goto berr; + if (!EVP_DigestFinal_ex(md, tmp, NULL)) + goto berr; + ret = memcmp(&(ctx->buf[ctx->buf_off]), tmp, md_size) == 0; + ctx->buf_off += md_size; + if (ret == 1) { + ctx->sigio = 0; + if (ctx->buf_len != ctx->buf_off) { + memmove(ctx->buf, &(ctx->buf[ctx->buf_off]), + ctx->buf_len - ctx->buf_off); + } + ctx->buf_len -= ctx->buf_off; + ctx->buf_off = 0; + } else { + ctx->cont = 0; + } + return 1; + berr: + BIO_clear_retry_flags(b); + return 0; +} + +static int block_out(BIO *b) +{ + BIO_OK_CTX *ctx; + EVP_MD_CTX *md; + unsigned long tl; + const EVP_MD *digest; + int md_size; + + ctx = BIO_get_data(b); + md = ctx->md; + digest = EVP_MD_CTX_md(md); + md_size = EVP_MD_size(digest); + + tl = ctx->buf_len - OK_BLOCK_BLOCK; + ctx->buf[0] = (unsigned char)(tl >> 24); + ctx->buf[1] = (unsigned char)(tl >> 16); + ctx->buf[2] = (unsigned char)(tl >> 8); + ctx->buf[3] = (unsigned char)(tl); + if (!EVP_DigestUpdate(md, + (unsigned char *)&(ctx->buf[OK_BLOCK_BLOCK]), tl)) + goto berr; + if (!EVP_DigestFinal_ex(md, &(ctx->buf[ctx->buf_len]), NULL)) + goto berr; + ctx->buf_len += md_size; + ctx->blockout = 1; + return 1; + berr: + BIO_clear_retry_flags(b); + return 0; +} + +static int block_in(BIO *b) +{ + BIO_OK_CTX *ctx; + EVP_MD_CTX *md; + unsigned long tl = 0; + unsigned char tmp[EVP_MAX_MD_SIZE]; + int md_size; + + ctx = BIO_get_data(b); + md = ctx->md; + md_size = EVP_MD_size(EVP_MD_CTX_md(md)); + + assert(sizeof(tl) >= OK_BLOCK_BLOCK); /* always true */ + tl = ctx->buf[0]; + tl <<= 8; + tl |= ctx->buf[1]; + tl <<= 8; + tl |= ctx->buf[2]; + tl <<= 8; + tl |= ctx->buf[3]; + + if (ctx->buf_len < tl + OK_BLOCK_BLOCK + md_size) + return 1; + + if (!EVP_DigestUpdate(md, + (unsigned char *)&(ctx->buf[OK_BLOCK_BLOCK]), tl)) + goto berr; + if (!EVP_DigestFinal_ex(md, tmp, NULL)) + goto berr; + if (memcmp(&(ctx->buf[tl + OK_BLOCK_BLOCK]), tmp, md_size) == 0) { + /* there might be parts from next block lurking around ! */ + ctx->buf_off_save = tl + OK_BLOCK_BLOCK + md_size; + ctx->buf_len_save = ctx->buf_len; + ctx->buf_off = OK_BLOCK_BLOCK; + ctx->buf_len = tl + OK_BLOCK_BLOCK; + ctx->blockout = 1; + } else { + ctx->cont = 0; + } + return 1; + berr: + BIO_clear_retry_flags(b); + return 0; +} |