This code uses "skey->keylen" as an memcpy() size and then checks that
it is valid on the next line. The other problem is that the check has
a potential integer overflow, it's better to use struct_size() for this.
Fixes: 23700da29b83 ("tipc: add automatic rekeying for encryption key")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
Hey Kees and Julia,
It would be nice to change tipc_aead_key_size() but I'm not sure how the
UAPI stuff works. My first attempt at to change it to
return struct_size(key, key, key->keylen);
broke the build. I think you guys used Coccinelle to automatically
update these calculations. Probably this wasn't updated because you
didn't want to break the build either?
net/tipc/crypto.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
index 40c44101fe8e..291ba276b835 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -2281,6 +2281,7 @@ static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
u16 key_gen = msg_key_gen(hdr);
u16 size = msg_data_sz(hdr);
u8 *data = msg_data(hdr);
+ u32 keylen;
spin_lock(&rx->lock);
if (unlikely(rx->skey || (key_gen == rx->key_gen && rx->key.keys))) {
@@ -2289,6 +2290,10 @@ static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
goto exit;
}
+ keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
+ if (struct_size(skey, key, keylen) != size)
+ goto exit;
+
/* Allocate memory for the key */
skey = kmalloc(size, GFP_ATOMIC);
if (unlikely(!skey)) {
@@ -2297,18 +2302,11 @@ static bool tipc_crypto_key_rcv(struct tipc_crypto *rx, struct tipc_msg *hdr)
}
/* Copy key from msg data */
- skey->keylen = ntohl(*((__be32 *)(data + TIPC_AEAD_ALG_NAME)));
+ skey->keylen = keylen;
memcpy(skey->alg_name, data, TIPC_AEAD_ALG_NAME);
memcpy(skey->key, data + TIPC_AEAD_ALG_NAME + sizeof(__be32),
skey->keylen);
- /* Sanity check */
- if (unlikely(size != tipc_aead_key_size(skey))) {
- kfree(skey);
- skey = NULL;
- goto exit;
- }
-
rx->key_gen = key_gen;
rx->skey_mode = msg_key_mode(hdr);
rx->skey = skey;
--
2.28.0
