Bugzilla # 2942 (https://bugzilla.mindrot.org/show_bug.cgi?id=2942)
During initialization a memory leak occurs in
ssh_set_newkeys().
During startup ssh_set_newkeys() is called twice, once with MODE_OUT
and once with MODE_IN.
Accordingly the ccp pointer points to state->send_context and
state->receive_context
At this time state->newkeys[mode] is stil NULL, so the if-clause
("rekeying") does not apply.
Further down cipher_init(ccp, ...) is called.
First thing that cipher_init() does is setting *ccp= NULL; which is be
equivalent to "state->send_context= NULL" (or
"state->send_context= NULL").
These point to memory blocks already.
The pointers are lost, the memory leaks.
Proposal: move
cipher_free(*ccp);
*ccp = NULL;
from the "rekeying" if-clause and place these two lines before calling
cipher_init().
A more conservative approach would be to add
if (*ccp!=NULL) {
cipher_free(*ccp);
*ccp = NULL;
}
before calling cipher_init().
diff --git a/packet.c b/packet.c
index dcf35e6..3a5a735 100644
--- a/packet.c
+++ b/packet.c
@@ -858,8 +858,6 @@ ssh_set_newkeys(struct ssh *ssh, int mode)
(unsigned long long)state->p_read.blocks,
(unsigned long long)state->p_send.bytes,
(unsigned long long)state->p_send.blocks);
- cipher_free(*ccp);
- *ccp = NULL;
kex_free_newkeys(state->newkeys[mode]);
state->newkeys[mode] = NULL;
}
@@ -878,6 +876,8 @@ ssh_set_newkeys(struct ssh *ssh, int mode)
}
mac->enabled = 1;
DBG(debug("cipher_init_context: %d", mode));
+ cipher_free(*ccp);
+ *ccp = NULL;
if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
enc->iv, enc->iv_len, crypt_type)) != 0)
return r;