denozord/strongswan-ext
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

pem: Properly handle encrypted PEM files without DEK-Info

Browse Source 
Since `key_size` remained zero, this caused a buffer overflow when the
derived key in `pem_decrypt()` was copied to the zero-length local
buffer.

Also fixed two potential memory leaks if hashing fails and make sure
the decryption key is wiped.

Fixes: 160f4c225d ("moved PEM parsing functionality to its own plugin")
This commit is contained in:
Tobias Brunner
2026-07-24 08:47:38 +02:00
parent 2367cda71e
commit 40f40973c0
1 changed files with 17 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/libstrongswan/plugins/pem/pem_builder.c
+17 -1
View File
@@ -96,6 +96,11 @@ static status_t pem_decrypt(chunk_t *blob, encryption_algorithm_t alg,
chunk_t key = {alloca(key_size), key_size};
uint8_t padding, *last_padding_pos, *first_padding_pos;
if (!key_size)
{
return FAILED;
}
/* build key from passphrase and IV */
hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5);
if (hasher == NULL)
@@ -108,6 +113,7 @@ static status_t pem_decrypt(chunk_t *blob, encryption_algorithm_t alg,
if (!hasher->get_hash(hasher, passphrase, NULL) ||
!hasher->get_hash(hasher, salt, hash.ptr))
{
hasher->destroy(hasher);
return FAILED;
}
memcpy(key.ptr, hash.ptr, hash.len);
@@ -118,6 +124,7 @@ static status_t pem_decrypt(chunk_t *blob, encryption_algorithm_t alg,
!hasher->get_hash(hasher, passphrase, NULL) ||
!hasher->get_hash(hasher, salt, hash.ptr))
{
hasher->destroy(hasher);
return FAILED;
}
memcpy(key.ptr + hash.len, hash.ptr, key.len - hash.len);
@@ -130,25 +137,29 @@ static status_t pem_decrypt(chunk_t *blob, encryption_algorithm_t alg,
{
DBG1(DBG_ASN, " %N encryption algorithm not available",
encryption_algorithm_names, alg);
memwipe(key.ptr, key.len);
return NOT_SUPPORTED;
}
if (iv.len != crypter->get_iv_size(crypter) ||
blob->len % crypter->get_block_size(crypter))
{
crypter->destroy(crypter);
DBG1(DBG_ASN, " data size is not multiple of block size");
crypter->destroy(crypter);
memwipe(key.ptr, key.len);
return PARSE_ERROR;
}
if (!crypter->set_key(crypter, key) ||
!crypter->decrypt(crypter, *blob, iv, &decrypted))
{
crypter->destroy(crypter);
memwipe(key.ptr, key.len);
return FAILED;
}
crypter->destroy(crypter);
memcpy(blob->ptr, decrypted.ptr, blob->len);
chunk_clear(&decrypted);
memwipe(key.ptr, key.len);
/* determine amount of padding */
last_padding_pos = blob->ptr + blob->len - 1;
@@ -340,6 +351,11 @@ static status_t pem_to_bin(chunk_t *blob, bool *pgp)
{
return SUCCESS;
}
if (alg == ENCR_UNDEFINED || !key_size)
{
DBG1(DBG_ASN, " encrypted PEM file has no valid DEK-Info");
return PARSE_ERROR;
}
enumerator = lib->credmgr->create_shared_enumerator(lib->credmgr,
SHARED_PRIVATE_KEY_PASS, NULL, NULL);