On 02/07/2013 10:24 AM, Daniel Borkmann wrote:
On 02/07/2013 04:04 PM, Vlad Yasevich wrote:
On 02/07/2013 05:55 AM, Daniel Borkmann wrote:
In sctp_auth_make_key_vector(), a sctp_auth_bytes structure is being
allocated, but without setting its object reference count, thus it's
initialized with a random value from the memory, which can lead to
i) premature free's of this object when being put (with possible
subsequent kernel panics), or ii) memory leaks when refcount has a
high value.
Fix this by using the appropriate sctp_auth_create_key() allocator,
which performs sanity checks, sets length and the refcount, as similar
done in sctp_auth_asoc_set_secret() and others. This bug seems to be
present since 2007 (1f485649f529: Implement SCTP-AUTH internals).
Not strictly a bug. The vectors are temporary and directly freed by
the caller. They are only used by sctp_auth_asoc_create_secret()
which builds the association secret key. The vectors are destroyed at
the end of that function using kfree() thus noone really cares about
the refcount on them and there are no leaks.
If you are going to convert to using sctp_auth_create_key() then you
need to convert the callers to user to use sctp_auth_key_put().
Otherwise you are leaking object counts.
Thanks for your feedback!
If Dave is okay with this, then:
- [PATCH net 2/2] net: sctp: sctp_auth_key_put: use kzfree instead of
kfree
- [PATCH net-next] net: sctp: sctp_auth_make_key_vector: remove
duplicate ntohs calls
can be applied as is. (If necessary, I could send the first one
_unchanged_ as a
single patch again, since it was part of a patchset. However, it will apply
cleanly as we have it right here.)
That's fine. Those 2 patches are ok.
Then, to avoid any future confusion and to stay consistent, I'll convert
this
to sctp_auth_create_key() API as well and make use of the
sctp_auth_key_put()
in a later possible patch *after* those two have been applied.
Fine by me.
-vlad
Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
---
net/sctp/auth.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/net/sctp/auth.c b/net/sctp/auth.c
index 159b9bc..55f1b06 100644
--- a/net/sctp/auth.c
+++ b/net/sctp/auth.c
@@ -205,12 +205,10 @@ static struct sctp_auth_bytes
*sctp_auth_make_key_vector(
if (chunks)
len += ntohs(chunks->param_hdr.length);
- new = kmalloc(sizeof(struct sctp_auth_bytes) + len, gfp);
+ new = sctp_auth_create_key(len, gfp);
if (!new)
return NULL;
- new->len = len;
-
memcpy(new->data, random, ntohs(random->param_hdr.length));
offset += ntohs(random->param_hdr.length);
--
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