In decrypt_internal(), a memory block 'mem' is allocated through kmalloc()
to hold aead_req, sgin[], sgout[], aad, and iv. This memory block should be
freed after it is used, before this function is returned. However, if the
return value of the function invocation of tls_do_decryption() is
-EINPROGRESS, this memory block is actually not freed, which is a memory
leak bug.
To fix this issue, free the allocated block before the error code
-EINPROGRESS is returned.
Signed-off-by: Wenwen Wang <[email protected]>
---
net/tls/tls_sw.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index b50ced8..22445bb 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1445,8 +1445,10 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
/* Prepare and submit AEAD request */
err = tls_do_decryption(sk, skb, sgin, sgout, iv,
data_len, aead_req, async);
- if (err == -EINPROGRESS)
+ if (err == -EINPROGRESS) {
+ kfree(mem);
return err;
+ }
/* Release the pages in case iov was mapped to pages */
for (; pages > 0; pages--)
--
2.7.4
On Wed, 24 Apr 2019 15:18:07 -0500, Wenwen Wang wrote:
> In decrypt_internal(), a memory block 'mem' is allocated through kmalloc()
> to hold aead_req, sgin[], sgout[], aad, and iv. This memory block should be
> freed after it is used, before this function is returned. However, if the
> return value of the function invocation of tls_do_decryption() is
> -EINPROGRESS, this memory block is actually not freed, which is a memory
> leak bug.
>
> To fix this issue, free the allocated block before the error code
> -EINPROGRESS is returned.
>
> Signed-off-by: Wenwen Wang <[email protected]>
Did you find this by code inspection or is this provable at runtime
(kmemleak or such)?
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index b50ced8..22445bb 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -1445,8 +1445,10 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
> /* Prepare and submit AEAD request */
> err = tls_do_decryption(sk, skb, sgin, sgout, iv,
> data_len, aead_req, async);
> - if (err == -EINPROGRESS)
> + if (err == -EINPROGRESS) {
> + kfree(mem);
> return err;
Mm... don't think so.
-EINPROGRESS is special, it means something is working on the request
asynchronously here.
I think this memory is freed in tls_decrypt_done():
kfree(aead_req);
Note that aead_req is the first member of the allocated buffer.
CCing Vakul
> + }
>
> /* Release the pages in case iov was mapped to pages */
> for (; pages > 0; pages--)
> -----Original Message-----
> From: Jakub Kicinski <[email protected]>
> Sent: Thursday, April 25, 2019 6:39 AM
> To: Wenwen Wang <[email protected]>
> Cc: Boris Pismenny <[email protected]>; Aviad Yehezkel
> <[email protected]>; Dave Watson <[email protected]>; John
> Fastabend <[email protected]>; Daniel Borkmann
> <[email protected]>; David S. Miller <[email protected]>; open
> list:NETWORKING [TLS] <[email protected]>; open list <linux-
> [email protected]>; Vakul Garg <[email protected]>
> Subject: Re: [PATCH] net: tls: fix a memory leak bug
>
> On Wed, 24 Apr 2019 15:18:07 -0500, Wenwen Wang wrote:
> > In decrypt_internal(), a memory block 'mem' is allocated through
> > kmalloc() to hold aead_req, sgin[], sgout[], aad, and iv. This memory
> > block should be freed after it is used, before this function is
> > returned. However, if the return value of the function invocation of
> > tls_do_decryption() is -EINPROGRESS, this memory block is actually not
> > freed, which is a memory leak bug.
> >
> > To fix this issue, free the allocated block before the error code
> > -EINPROGRESS is returned.
> >
> > Signed-off-by: Wenwen Wang <[email protected]>
>
> Did you find this by code inspection or is this provable at runtime (kmemleak
> or such)?
>
> > diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index
> > b50ced8..22445bb 100644
> > --- a/net/tls/tls_sw.c
> > +++ b/net/tls/tls_sw.c
> > @@ -1445,8 +1445,10 @@ static int decrypt_internal(struct sock *sk,
> struct sk_buff *skb,
> > /* Prepare and submit AEAD request */
> > err = tls_do_decryption(sk, skb, sgin, sgout, iv,
> > data_len, aead_req, async);
> > - if (err == -EINPROGRESS)
> > + if (err == -EINPROGRESS) {
> > + kfree(mem);
> > return err;
>
> Mm... don't think so.
>
> -EINPROGRESS is special, it means something is working on the request
> asynchronously here.
>
> I think this memory is freed in tls_decrypt_done():
>
> kfree(aead_req);
>
> Note that aead_req is the first member of the allocated buffer.
>
> CCing Vakul
The patch is wrong.
Valid reasons have been given against the patch.
>
> > + }
> >
> > /* Release the pages in case iov was mapped to pages */
> > for (; pages > 0; pages--)