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authorThomas Snider <tjps636@gmail.com>2017-03-23 14:07:51 -0700
committerThomas Snider <tjps636@gmail.com>2017-05-03 11:35:51 -0700
commit6c914ac176624468c66febdb1ad0e24ff2118a5f (patch)
tree546c1239d37a4ab6fec953d1660ae4829310a97e /src
parente2b99b13131b5d0fd6fae6d55892c2ebb327d438 (diff)
[wallet] Securely erase potentially sensitive keys/values
Diffstat (limited to 'src')
-rw-r--r--src/support/cleanse.h1
-rw-r--r--src/wallet/db.h43
2 files changed, 23 insertions, 21 deletions
diff --git a/src/support/cleanse.h b/src/support/cleanse.h
index 3e02aa8fd1..f020216c73 100644
--- a/src/support/cleanse.h
+++ b/src/support/cleanse.h
@@ -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
diff --git a/src/wallet/db.h b/src/wallet/db.h
index 1a46448cc7..3c6870d169 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -180,22 +180,23 @@ public:
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;
-
- // 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;
+ 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'
+ }
+
+ // 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>
@@ -222,8 +223,8 @@ public:
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);
}
@@ -245,7 +246,7 @@ public:
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);
}
@@ -265,7 +266,7 @@ public:
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);
}
@@ -308,8 +309,8 @@ public:
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;