diff options
Diffstat (limited to 'app/openssl/crypto/modes/ctr128.c')
-rw-r--r-- | app/openssl/crypto/modes/ctr128.c | 92 |
1 files changed, 80 insertions, 12 deletions
diff --git a/app/openssl/crypto/modes/ctr128.c b/app/openssl/crypto/modes/ctr128.c index 932037f5..ee642c58 100644 --- a/app/openssl/crypto/modes/ctr128.c +++ b/app/openssl/crypto/modes/ctr128.c @@ -48,7 +48,8 @@ * */ -#include "modes.h" +#include <openssl/crypto.h> +#include "modes_lcl.h" #include <string.h> #ifndef MODES_DEBUG @@ -58,17 +59,6 @@ #endif #include <assert.h> -typedef unsigned int u32; -typedef unsigned char u8; - -#define STRICT_ALIGNMENT -#if defined(__i386) || defined(__i386__) || \ - defined(__x86_64) || defined(__x86_64__) || \ - defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ - defined(__s390__) || defined(__s390x__) -# undef STRICT_ALIGNMENT -#endif - /* NOTE: the IV/counter CTR mode is big-endian. The code itself * is endian-neutral. */ @@ -182,3 +172,81 @@ void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out, *num=n; } + +/* increment upper 96 bits of 128-bit counter by 1 */ +static void ctr96_inc(unsigned char *counter) { + u32 n=12; + u8 c; + + do { + --n; + c = counter[n]; + ++c; + counter[n] = c; + if (c) return; + } while (n); +} + +void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out, + size_t len, const void *key, + unsigned char ivec[16], unsigned char ecount_buf[16], + unsigned int *num, ctr128_f func) +{ + unsigned int n,ctr32; + + assert(in && out && key && ecount_buf && num); + assert(*num < 16); + + n = *num; + + while (n && len) { + *(out++) = *(in++) ^ ecount_buf[n]; + --len; + n = (n+1) % 16; + } + + ctr32 = GETU32(ivec+12); + while (len>=16) { + size_t blocks = len/16; + /* + * 1<<28 is just a not-so-small yet not-so-large number... + * Below condition is practically never met, but it has to + * be checked for code correctness. + */ + if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28)) + blocks = (1U<<28); + /* + * As (*func) operates on 32-bit counter, caller + * has to handle overflow. 'if' below detects the + * overflow, which is then handled by limiting the + * amount of blocks to the exact overflow point... + */ + ctr32 += (u32)blocks; + if (ctr32 < blocks) { + blocks -= ctr32; + ctr32 = 0; + } + (*func)(in,out,blocks,key,ivec); + /* (*ctr) does not update ivec, caller does: */ + PUTU32(ivec+12,ctr32); + /* ... overflow was detected, propogate carry. */ + if (ctr32 == 0) ctr96_inc(ivec); + blocks *= 16; + len -= blocks; + out += blocks; + in += blocks; + } + if (len) { + memset(ecount_buf,0,16); + (*func)(ecount_buf,ecount_buf,1,key,ivec); + ++ctr32; + PUTU32(ivec+12,ctr32); + if (ctr32 == 0) ctr96_inc(ivec); + while (len--) { + out[n] = in[n] ^ ecount_buf[n]; + ++n; + } + } + + *num=n; +} |