diff options
| author | Matt Caswell <matt@openssl.org> | 2016-07-01 11:58:05 +0100 |
|---|---|---|
| committer | Matt Caswell <matt@openssl.org> | 2016-07-01 19:23:29 +0100 |
| commit | 1e16987fc18cce9420dd3b76326b8d25746fa258 (patch) | |
| tree | 6f75e4d53d4e9fab2c5dce50b21998db6e77f398 /ssl | |
| parent | 43cb309053ed3518bdd75dbf05ee96485ea57742 (diff) | |
Avoid an overflow in constructing the ServerKeyExchange message
We calculate the size required for the ServerKeyExchange message and then
call BUF_MEM_grow_clean() on the buffer. However we fail to take account of
2 bytes required for the signature algorithm and 2 bytes for the signature
length, i.e. we could overflow by 4 bytes. In reality this won't happen
because the buffer is pre-allocated to a large size that means it should be
big enough anyway.
Addresses an OCAP Audit issue.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Diffstat (limited to 'ssl')
| -rw-r--r-- | ssl/statem/statem_srvr.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c index a88b3219ad..773591cd38 100644 --- a/ssl/statem/statem_srvr.c +++ b/ssl/statem/statem_srvr.c @@ -1792,6 +1792,11 @@ int tls_construct_server_key_exchange(SSL *s) goto f_err; } kn = EVP_PKEY_size(pkey); + /* Allow space for signature algorithm */ + if (SSL_USE_SIGALGS(s)) + kn += 2; + /* Allow space for signature length */ + kn += 2; } else { pkey = NULL; kn = 0; |