[PATCH net] xfrm: prevent some integer overflows in verify_ functions
From: Dan Carpenter <hidden>
Date: 2024-12-17 08:42:41
Also in:
kernel-janitors, lkml
Subsystem:
networking [general], networking [ipsec], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds
The xfrm_alg_len() type functions take the alg->alg_key_len which
is the length in bits and converts it to bytes and add it to
sizeof(*alg).
return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
The alg->alg_key_len is type unsigned int. That means that if we pick
an ->alg_key_len which is greater than "UINT_MAX - 7" it leads to an
integer overflow and the key length is treated as zero. The result
is that xfrm_alg_len() function will return "sizeof(*alg) + 0".
However, so far as I can see this does not cause a problem. All the
places which use this length consistently do the same conversion. The
type of thing I was looking for would be code which uses partial keys
or code which uses a different type instead of u32 for ->alg_key_len.
I didn't find anything like that so I can't see a negative impact from
this bug. Still fixing it is the right thing to do.
Fixes: 31c26852cb2a ("[IPSEC]: Verify key payload in verify_one_algo")
Signed-off-by: Dan Carpenter <redacted>
---
net/xfrm/xfrm_user.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 08c6d6f0179f..686c6a24d92b 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c@@ -45,6 +45,10 @@ static int verify_one_alg(struct nlattr **attrs, enum xfrm_attr_type_t type, return 0; algp = nla_data(rt); + if (algp->alg_key_len > INT_MAX) { + NL_SET_ERR_MSG(extack, "Invalid AUTH/CRYPT/COMP key length"); + return -EINVAL; + } if (nla_len(rt) < (int)xfrm_alg_len(algp)) { NL_SET_ERR_MSG(extack, "Invalid AUTH/CRYPT/COMP attribute length"); return -EINVAL;
@@ -75,6 +79,10 @@ static int verify_auth_trunc(struct nlattr **attrs, return 0; algp = nla_data(rt); + if (algp->alg_key_len > INT_MAX) { + NL_SET_ERR_MSG(extack, "Invalid AUTH_TRUNC key length"); + return -EINVAL; + } if (nla_len(rt) < (int)xfrm_alg_auth_len(algp)) { NL_SET_ERR_MSG(extack, "Invalid AUTH_TRUNC attribute length"); return -EINVAL;
@@ -93,6 +101,10 @@ static int verify_aead(struct nlattr **attrs, struct netlink_ext_ack *extack) return 0; algp = nla_data(rt); + if (algp->alg_key_len > INT_MAX) { + NL_SET_ERR_MSG(extack, "Invalid AEAD key length"); + return -EINVAL; + } if (nla_len(rt) < (int)aead_len(algp)) { NL_SET_ERR_MSG(extack, "Invalid AEAD attribute length"); return -EINVAL;
--
2.45.2