kris/boringssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

modes/ctr.c: Ensure ecount_buf alignment in CRYPTO_ctr128_encrypt.

Browse Source 
This isn't a problem when called from EVP, since the buffer is
aligned in the EVP_CIPHER_CTX. The increment counter code is also
fixed to deal with overflow.

(Imported from upstream's 6533a0b8d1ed12aa5f7dfd7a429eec67c5486bb5)

Change-Id: I8d7191c3d3873db254a551085d2358d90bc8397a
Reviewed-on: https://boringssl-review.googlesource.com/7233
Reviewed-by: David Benjamin <davidben@google.com>
This commit is contained in:
Steven Valdez 2016-02-29 10:14:11 -05:00 committed by David Benjamin
parent df1dc98409
commit 318c076b69
1 changed files with 10 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
crypto/modes/ctr.c
View File

@ -59,17 +59,13 @@
/* increment counter (128-bit int) by 1 */
static void ctr128_inc(uint8_t *counter) {
uint32_t n = 16;
uint8_t c;
uint32_t n = 16, c = 1;
do {
--n;
c = counter[n];
++c;
counter[n] = c;
if (c) {
return;
}
c += counter[n];
counter[n] = (uint8_t) c;
c >>= 8;
} while (n);
}
@ -104,7 +100,7 @@ void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
}
#if STRICT_ALIGNMENT
if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
if (((size_t)in | (size_t)out | (size_t)ecount_buf) % sizeof(size_t) != 0) {
size_t l = 0;
while (l < len) {
if (n == 0) {
@ -124,7 +120,7 @@ void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
while (len >= 16) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
for (; n < 16; n += sizeof(size_t)) {
for (n = 0; n < 16; n += sizeof(size_t)) {
*(size_t *)(out + n) = *(const size_t *)(in + n) ^
*(const size_t *)(ecount_buf + n);
}
@ -146,17 +142,14 @@ void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
/* increment upper 96 bits of 128-bit counter by 1 */
static void ctr96_inc(uint8_t *counter) {
uint32_t n = 12;
uint32_t n = 12, c = 1;
uint8_t c;
do {
--n;
c = counter[n];
++c;
counter[n] = c;
if (c) {
return;
}
c += counter[n];
counter[n] = (uint8_t) c;
c >>= 8;
} while (n);
}