v2: Added "Fixes" tags to the patches.
WARN_ON() for XFRMA_UNSPEC translation which likely no-one except
syzkaller uses; properly zerofy tail-padding for 64-bit attribute;
don't use __GFP_ZERO as the memory is initialized during translation.
Cc: Steffen Klassert <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: [email protected]
Thanks,
Dmitry
Dmitry Safonov (3):
xfrm/compat: Translate by copying XFRMA_UNSPEC attribute
xfrm/compat: memset(0) 64-bit padding at right place
xfrm/compat: Don't allocate memory with __GFP_ZERO
net/xfrm/xfrm_compat.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
base-commit: 3cea11cd5e3b00d91caf0b4730194039b45c5891
--
2.28.0
xfrm_xlate32() translates 64-bit message provided by kernel to be sent
for 32-bit listener (acknowledge or monitor). Translator code doesn't
expect XFRMA_UNSPEC attribute as it doesn't know its payload.
Kernel never attaches such attribute, but a user can.
I've searched if any opensource does it and the answer is no.
Nothing on github and google finds only tfcproject that has such code
commented-out.
What will happen if a user sends a netlink message with XFRMA_UNSPEC
attribute? Ipsec code ignores this attribute. But if there is a
monitor-process or 32-bit user requested ack - kernel will try to
translate such message and will hit WARN_ONCE() in xfrm_xlate64_attr().
Deal with XFRMA_UNSPEC by copying the attribute payload with
xfrm_nla_cpy(). In result, the default switch-case in xfrm_xlate64_attr()
becomes an unused code. Leave those 3 lines in case a new xfrm attribute
will be added.
Fixes: 5461fc0c8d9f ("xfrm/compat: Add 64=>32-bit messages translator")
Reported-by: [email protected]
Signed-off-by: Dmitry Safonov <[email protected]>
---
net/xfrm/xfrm_compat.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c
index e28f0c9ecd6a..17edbf935e35 100644
--- a/net/xfrm/xfrm_compat.c
+++ b/net/xfrm/xfrm_compat.c
@@ -234,6 +234,7 @@ static int xfrm_xlate64_attr(struct sk_buff *dst, const struct nlattr *src)
case XFRMA_PAD:
/* Ignore */
return 0;
+ case XFRMA_UNSPEC:
case XFRMA_ALG_AUTH:
case XFRMA_ALG_CRYPT:
case XFRMA_ALG_COMP:
--
2.28.0
32-bit messages translated by xfrm_compat can have attributes attached.
For all, but XFRMA_SA, XFRMA_POLICY the size of payload is the same
in 32-bit UABI and 64-bit UABI. For XFRMA_SA (struct xfrm_usersa_info)
and XFRMA_POLICY (struct xfrm_userpolicy_info) it's only tail-padding
that is present in 64-bit payload, but not in 32-bit.
The proper size for destination nlattr is already calculated by
xfrm_user_rcv_calculate_len64() and allocated with kvmalloc().
xfrm_attr_cpy32() copies 32-bit copy_len into 64-bit attribute
translated payload, zero-filling possible padding for SA/POLICY.
Due to a typo, *pos already has 64-bit payload size, in a result next
memset(0) is called on the memory after the translated attribute, not on
the tail-padding of it.
Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator")
Reported-by: [email protected]
Signed-off-by: Dmitry Safonov <[email protected]>
---
net/xfrm/xfrm_compat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c
index 17edbf935e35..556e9f33b815 100644
--- a/net/xfrm/xfrm_compat.c
+++ b/net/xfrm/xfrm_compat.c
@@ -388,7 +388,7 @@ static int xfrm_attr_cpy32(void *dst, size_t *pos, const struct nlattr *src,
memcpy(nla, src, nla_attr_size(copy_len));
nla->nla_len = nla_attr_size(payload);
- *pos += nla_attr_size(payload);
+ *pos += nla_attr_size(copy_len);
nlmsg->nlmsg_len += nla->nla_len;
memset(dst + *pos, 0, payload - copy_len);
--
2.28.0
32-bit to 64-bit messages translator zerofies needed paddings in the
translation, the rest is the actual payload.
Don't allocate zero pages as they are not needed.
Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator")
Signed-off-by: Dmitry Safonov <[email protected]>
---
net/xfrm/xfrm_compat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_compat.c b/net/xfrm/xfrm_compat.c
index 556e9f33b815..d8e8a11ca845 100644
--- a/net/xfrm/xfrm_compat.c
+++ b/net/xfrm/xfrm_compat.c
@@ -564,7 +564,7 @@ static struct nlmsghdr *xfrm_user_rcv_msg_compat(const struct nlmsghdr *h32,
return NULL;
len += NLMSG_HDRLEN;
- h64 = kvmalloc(len, GFP_KERNEL | __GFP_ZERO);
+ h64 = kvmalloc(len, GFP_KERNEL);
if (!h64)
return ERR_PTR(-ENOMEM);
--
2.28.0
On Mon, Nov 02, 2020 at 04:14:44PM +0000, Dmitry Safonov wrote:
> v2: Added "Fixes" tags to the patches.
>
> WARN_ON() for XFRMA_UNSPEC translation which likely no-one except
> syzkaller uses; properly zerofy tail-padding for 64-bit attribute;
> don't use __GFP_ZERO as the memory is initialized during translation.
>
> Cc: Steffen Klassert <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Herbert Xu <[email protected]>
> Cc: Hillf Danton <[email protected]>
> Cc: [email protected]
>
> Thanks,
> Dmitry
>
> Dmitry Safonov (3):
> xfrm/compat: Translate by copying XFRMA_UNSPEC attribute
> xfrm/compat: memset(0) 64-bit padding at right place
> xfrm/compat: Don't allocate memory with __GFP_ZERO
Series applied, thanks a lot Dmitry!