svn commit: r339787 - head/sys/crypto/rijndael
Conrad Meyer
cem at FreeBSD.org
Fri Oct 26 20:53:02 UTC 2018
Author: cem
Date: Fri Oct 26 20:53:01 2018
New Revision: 339787
URL: https://svnweb.freebsd.org/changeset/base/339787
Log:
rijndael (AES): Avoid leaking sensitive data on kernel stack
Noticed this investigating Fortuna. Remove useless duplicate stack copies
of sensitive contents when possible, or if not possible, be sure to zero
them out when we're finished.
Approved by: secteam (gordon)
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D16935
Modified:
head/sys/crypto/rijndael/rijndael-api-fst.c
Modified: head/sys/crypto/rijndael/rijndael-api-fst.c
==============================================================================
--- head/sys/crypto/rijndael/rijndael-api-fst.c Fri Oct 26 20:07:46 2018 (r339786)
+++ head/sys/crypto/rijndael/rijndael-api-fst.c Fri Oct 26 20:53:01 2018 (r339787)
@@ -36,7 +36,6 @@ typedef u_int8_t BYTE;
int rijndael_makeKey(keyInstance *key, BYTE direction, int keyLen,
const char *keyMaterial) {
- u_int8_t cipherKey[RIJNDAEL_MAXKB];
if (key == NULL) {
return BAD_KEY_INSTANCE;
@@ -59,13 +58,12 @@ int rijndael_makeKey(keyInstance *key, BYTE direction,
}
/* initialize key schedule: */
- memcpy(cipherKey, key->keyMaterial, keyLen/8);
if (direction == DIR_ENCRYPT) {
- key->Nr = rijndaelKeySetupEnc(key->rk, cipherKey, keyLen);
+ key->Nr = rijndaelKeySetupEnc(key->rk, key->keyMaterial, keyLen);
} else {
- key->Nr = rijndaelKeySetupDec(key->rk, cipherKey, keyLen);
+ key->Nr = rijndaelKeySetupDec(key->rk, key->keyMaterial, keyLen);
}
- rijndaelKeySetupEnc(key->ek, cipherKey, keyLen);
+ rijndaelKeySetupEnc(key->ek, key->keyMaterial, keyLen);
return TRUE;
}
@@ -186,6 +184,7 @@ int rijndael_blockEncrypt(cipherInstance *cipher, keyI
return BAD_CIPHER_STATE;
}
+ explicit_bzero(block, sizeof(block));
return 128*numBlocks;
}
@@ -258,6 +257,7 @@ int rijndael_padEncrypt(cipherInstance *cipher, keyIns
return BAD_CIPHER_STATE;
}
+ explicit_bzero(block, sizeof(block));
return 16*(numBlocks + 1);
}
@@ -357,12 +357,13 @@ int rijndael_blockDecrypt(cipherInstance *cipher, keyI
return BAD_CIPHER_STATE;
}
+ explicit_bzero(block, sizeof(block));
return 128*numBlocks;
}
int rijndael_padDecrypt(cipherInstance *cipher, keyInstance *key,
const BYTE *input, int inputOctets, BYTE *outBuffer) {
- int i, numBlocks, padLen;
+ int i, numBlocks, padLen, rval;
u_int8_t block[16];
u_int32_t iv[4];
@@ -392,11 +393,13 @@ int rijndael_padDecrypt(cipherInstance *cipher, keyIns
rijndaelDecrypt(key->rk, key->Nr, input, block);
padLen = block[15];
if (padLen >= 16) {
- return BAD_DATA;
+ rval = BAD_DATA;
+ goto out;
}
for (i = 16 - padLen; i < 16; i++) {
if (block[i] != padLen) {
- return BAD_DATA;
+ rval = BAD_DATA;
+ goto out;
}
}
memcpy(outBuffer, block, 16 - padLen);
@@ -424,11 +427,13 @@ int rijndael_padDecrypt(cipherInstance *cipher, keyIns
((u_int32_t*)block)[3] ^= iv[3];
padLen = block[15];
if (padLen <= 0 || padLen > 16) {
- return BAD_DATA;
+ rval = BAD_DATA;
+ goto out;
}
for (i = 16 - padLen; i < 16; i++) {
if (block[i] != padLen) {
- return BAD_DATA;
+ rval = BAD_DATA;
+ goto out;
}
}
memcpy(outBuffer, block, 16 - padLen);
@@ -438,5 +443,9 @@ int rijndael_padDecrypt(cipherInstance *cipher, keyIns
return BAD_CIPHER_STATE;
}
- return 16*numBlocks - padLen;
+ rval = 16*numBlocks - padLen;
+
+out:
+ explicit_bzero(block, sizeof(block));
+ return rval;
}
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