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[wallet] Securely erase potentially sensitive keys/values

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Github-Pull: #10308
Rebased-From: 6c914ac176
This commit is contained in:
Thomas Snider
2017-03-23 14:07:51 -07:00
committed by Luke Dashjr
parent ff13f592c5
commit 28b8b8b603
2 changed files with 22 additions and 20 deletions
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1
src/support/cleanse.h
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@@ -8,6 +8,7 @@
#include <stdlib.h>
// Attempt to overwrite data in the specified memory span.
void memory_cleanse(void *ptr, size_t len);
#endif // BITCOIN_SUPPORT_CLEANSE_H

41
src/wallet/db.h
View File

@@ -126,22 +126,23 @@ protected:
Dbt datValue;
datValue.set_flags(DB_DBT_MALLOC);
int ret = pdb->get(activeTxn, &datKey, &datValue, 0);
memset(datKey.get_data(), 0, datKey.get_size());
if (datValue.get_data() == NULL)
return false;
memory_cleanse(datKey.get_data(), datKey.get_size());
bool success = false;
if (datValue.get_data() != NULL) {
// Unserialize value
try {
CDataStream ssValue((char*)datValue.get_data(), (char*)datValue.get_data() + datValue.get_size(), SER_DISK, CLIENT_VERSION);
ssValue >> value;
success = true;
} catch (const std::exception&) {
// In this case success remains 'false'
}
// Unserialize value
try {
CDataStream ssValue((char*)datValue.get_data(), (char*)datValue.get_data() + datValue.get_size(), SER_DISK, CLIENT_VERSION);
ssValue >> value;
} catch (const std::exception&) {
return false;
// Clear and free memory
memory_cleanse(datValue.get_data(), datValue.get_size());
free(datValue.get_data());
}
// Clear and free memory
memset(datValue.get_data(), 0, datValue.get_size());
free(datValue.get_data());
return (ret == 0);
return ret == 0 && success;
}
template <typename K, typename T>
@@ -168,8 +169,8 @@ protected:
int ret = pdb->put(activeTxn, &datKey, &datValue, (fOverwrite ? 0 : DB_NOOVERWRITE));
// Clear memory in case it was a private key
memset(datKey.get_data(), 0, datKey.get_size());
memset(datValue.get_data(), 0, datValue.get_size());
memory_cleanse(datKey.get_data(), datKey.get_size());
memory_cleanse(datValue.get_data(), datValue.get_size());
return (ret == 0);
}
@@ -191,7 +192,7 @@ protected:
int ret = pdb->del(activeTxn, &datKey, 0);
// Clear memory
memset(datKey.get_data(), 0, datKey.get_size());
memory_cleanse(datKey.get_data(), datKey.get_size());
return (ret == 0 || ret == DB_NOTFOUND);
}
@@ -211,7 +212,7 @@ protected:
int ret = pdb->exists(activeTxn, &datKey, 0);
// Clear memory
memset(datKey.get_data(), 0, datKey.get_size());
memory_cleanse(datKey.get_data(), datKey.get_size());
return (ret == 0);
}
@@ -254,8 +255,8 @@ protected:
ssValue.write((char*)datValue.get_data(), datValue.get_size());
// Clear and free memory
memset(datKey.get_data(), 0, datKey.get_size());
memset(datValue.get_data(), 0, datValue.get_size());
memory_cleanse(datKey.get_data(), datKey.get_size());
memory_cleanse(datValue.get_data(), datValue.get_size());
free(datKey.get_data());
free(datValue.get_data());
return 0;