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Fix ccm_memory() cleaning user-supplied key #327

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Merged
sjaeckel merged 2 commits into from
Nov 20, 2017
Merged

Fix ccm_memory() cleaning user-supplied key #327

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e05097e
fix segfault in ccm_memory() with LTC_CLEAN_STACK
sjaeckel Nov 10, 2017
2a5f5cf
test that ccm_memory() doesn't touch user-supplied key
sjaeckel Nov 10, 2017
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4 changes: 3 additions & 1 deletion src/encauth/ccm/ccm_memory.c
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Original file line number Diff line number Diff line change
Expand Up @@ -333,6 +333,9 @@ int ccm_memory(int cipher,

if (skey != uskey) {
cipher_descriptor[cipher].done(skey);
#ifdef LTC_CLEAN_STACK
zeromem(skey, sizeof(*skey));
#endif
}

if (direction == CCM_ENCRYPT) {
Expand Down Expand Up @@ -380,7 +383,6 @@ int ccm_memory(int cipher,
fastMask = 0;
#endif
mask = 0;
zeromem(skey, sizeof(*skey));
zeromem(PAD, sizeof(PAD));
zeromem(CTRPAD, sizeof(CTRPAD));
if (pt_work != NULL) {
Expand Down
11 changes: 11 additions & 0 deletions src/encauth/ccm/ccm_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,17 @@ int ccm_test(void)
tag, &taglen, 0)) != CRYPT_OK) {
return err;
}
/* run a second time to make sure skey is not touched */
if ((err = ccm_memory(idx,
tests[x].key, 16,
&skey,
tests[x].nonce, tests[x].noncelen,
tests[x].header, tests[x].headerlen,
(unsigned char*)tests[x].pt, tests[x].ptlen,
buf,
tag, &taglen, 0)) != CRYPT_OK) {
return err;
}
} else {
if ((err = ccm_init(&ccm, idx, tests[x].key, 16, tests[x].ptlen, tests[x].taglen, tests[x].headerlen)) != CRYPT_OK) {
return err;
Expand Down