The NCP code does a strcmp(options->ciphername, ...) without first checking
whether options->ciphername is NULL. This could cause a crash when using
"--cipher none". This patch fixes that problem by ensuring that
options->ciphername (and options->authname) are never NULL. Ensuring that
options->ciphername is never null prevents us from having to write null
checks everywhere.
Signed-off-by: Steffan Karger <stef...@karger.me>
---
src/openvpn/crypto.c | 7 +++++--
src/openvpn/init.c | 2 +-
src/openvpn/options.c | 8 --------
3 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index 1b17f9d..3dd4a9e 100644
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -759,8 +759,11 @@ init_key_type (struct key_type *kt, const char *ciphername,
{
bool aead_cipher = false;
+ ASSERT(ciphername);
+ ASSERT(authname);
+
CLEAR (*kt);
- if (ciphername)
+ if (strcmp (ciphername, "none") != 0)
{
kt->cipher = cipher_kt_get
(translate_cipher_name_from_openvpn(ciphername));
if (!kt->cipher)
@@ -790,7 +793,7 @@ init_key_type (struct key_type *kt, const char *ciphername,
if (warn)
msg (M_WARN, "******* WARNING *******: null cipher specified, no
encryption will be used");
}
- if (authname)
+ if (strcmp (authname, "none") != 0)
{
if (!aead_cipher) { /* Ignore auth for AEAD ciphers */
kt->digest = md_kt_get (authname);
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 9cbbe9d..49f4220 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -2259,7 +2259,7 @@ do_init_crypto_tls_c1 (struct context *c)
/* Initialize key_type for tls-auth with auth only */
CLEAR (c->c1.ks.tls_auth_key_type);
- if (options->authname)
+ if (!streq (options->authname, "none"))
{
c->c1.ks.tls_auth_key_type.digest = md_kt_get (options->authname);
c->c1.ks.tls_auth_key_type.hmac_length =
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 1358237..53b4617 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -6653,19 +6653,11 @@ add_option (struct options *options,
{
VERIFY_PERMISSION (OPT_P_GENERAL);
options->authname = p[1];
- if (streq (options->authname, "none"))
- {
- options->authname = NULL;
- }
}
else if (streq (p[0], "cipher") && p[1] && !p[2])
{
VERIFY_PERMISSION (OPT_P_NCP);
options->ciphername = p[1];
- if (streq (options->ciphername, "none"))
- {
- options->ciphername = NULL;
- }
}
else if (streq (p[0], "ncp-ciphers") && p[1] && !p[2])
{
--
2.7.4
------------------------------------------------------------------------------
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