* [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return
@ 2021-08-18 3:25 Dongliang Mu
2021-08-18 3:32 ` Herbert Xu
0 siblings, 1 reply; 4+ messages in thread
From: Dongliang Mu @ 2021-08-18 3:25 UTC (permalink / raw)
To: Steffen Klassert, Herbert Xu, David S. Miller, Jakub Kicinski
Cc: dan.carpenter, Dongliang Mu, syzbot+b9cfd1cc5d57ee0a09ab, stable,
netdev, linux-kernel
In ipcomp_alloc_scratches, if the vmalloc fails, there leaves an oudated
pointer in *per_cpu_ptr(scratches, i). However, in the error handling of
ipcomp_init_state, if ipcomp_alloc_scratches fails, it will invoke
ipcomp_free_scratches directly. This functio will vfree the per_cpu_ptr
pointer. If the pointer points to an invalid memory, the kernel crashes.
Fix this by moving the assignment of per_cpu_ptr point before return.
Call Trace:
ipcomp_free_scratches+0xbc/0x160 net/xfrm/xfrm_ipcomp.c:203
ipcomp_free_data net/xfrm/xfrm_ipcomp.c:312 [inline]
ipcomp_init_state+0x77c/0xa40 net/xfrm/xfrm_ipcomp.c:364
ipcomp6_init_state+0xc2/0x700 net/ipv6/ipcomp6.c:154
__xfrm_init_state+0x995/0x15c0 net/xfrm/xfrm_state.c:2648
xfrm_init_state+0x1a/0x70 net/xfrm/xfrm_state.c:2675
pfkey_msg2xfrm_state net/key/af_key.c:1287 [inline]
pfkey_add+0x1a64/0x2cd0 net/key/af_key.c:1504
pfkey_process+0x685/0x7e0 net/key/af_key.c:2837
pfkey_sendmsg+0x43a/0x820 net/key/af_key.c:3676
sock_sendmsg_nosec net/socket.c:703 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:723
Reported-by: syzbot+b9cfd1cc5d57ee0a09ab@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Fixes: 6fccab671f2f ("ipsec: ipcomp - Merge IPComp impl")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
net/xfrm/xfrm_ipcomp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index cb40ff0ff28d..01dbec70dfba 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -223,9 +223,9 @@ static void * __percpu *ipcomp_alloc_scratches(void)
void *scratch;
scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
+ *per_cpu_ptr(scratches, i) = scratch;
if (!scratch)
return NULL;
- *per_cpu_ptr(scratches, i) = scratch;
}
return scratches;
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return
2021-08-18 3:25 [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return Dongliang Mu
@ 2021-08-18 3:32 ` Herbert Xu
2021-08-18 10:39 ` Dongliang Mu
0 siblings, 1 reply; 4+ messages in thread
From: Herbert Xu @ 2021-08-18 3:32 UTC (permalink / raw)
To: Dongliang Mu
Cc: Steffen Klassert, David S. Miller, Jakub Kicinski, dan.carpenter,
syzbot+b9cfd1cc5d57ee0a09ab, stable, netdev, linux-kernel
On Wed, Aug 18, 2021 at 11:25:53AM +0800, Dongliang Mu wrote:
>
> diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
> index cb40ff0ff28d..01dbec70dfba 100644
> --- a/net/xfrm/xfrm_ipcomp.c
> +++ b/net/xfrm/xfrm_ipcomp.c
> @@ -223,9 +223,9 @@ static void * __percpu *ipcomp_alloc_scratches(void)
> void *scratch;
>
> scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
> + *per_cpu_ptr(scratches, i) = scratch;
> if (!scratch)
> return NULL;
> - *per_cpu_ptr(scratches, i) = scratch;
scratches comes from alloc_percpu so it should already be zeroed.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return
2021-08-18 3:32 ` Herbert Xu
@ 2021-08-18 10:39 ` Dongliang Mu
2021-08-18 12:48 ` Herbert Xu
0 siblings, 1 reply; 4+ messages in thread
From: Dongliang Mu @ 2021-08-18 10:39 UTC (permalink / raw)
To: Herbert Xu
Cc: Steffen Klassert, David S. Miller, Jakub Kicinski, Dan Carpenter,
syzbot+b9cfd1cc5d57ee0a09ab, stable,
open list:NETWORKING [GENERAL],
linux-kernel
On Wed, Aug 18, 2021 at 11:32 AM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Wed, Aug 18, 2021 at 11:25:53AM +0800, Dongliang Mu wrote:
> >
> > diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
> > index cb40ff0ff28d..01dbec70dfba 100644
> > --- a/net/xfrm/xfrm_ipcomp.c
> > +++ b/net/xfrm/xfrm_ipcomp.c
> > @@ -223,9 +223,9 @@ static void * __percpu *ipcomp_alloc_scratches(void)
> > void *scratch;
> >
> > scratch = vmalloc_node(IPCOMP_SCRATCH_SIZE, cpu_to_node(i));
> > + *per_cpu_ptr(scratches, i) = scratch;
> > if (!scratch)
> > return NULL;
> > - *per_cpu_ptr(scratches, i) = scratch;
>
> scratches comes from alloc_percpu so it should already be zeroed.
Correct.
:\ Then I have no idea how this crash occurs. This crash report does
not have any reproducer. It seems like a random crash, but I am not
sure.
If you have any patch for this crash, please let me know.
>
> Cheers,
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return
2021-08-18 10:39 ` Dongliang Mu
@ 2021-08-18 12:48 ` Herbert Xu
0 siblings, 0 replies; 4+ messages in thread
From: Herbert Xu @ 2021-08-18 12:48 UTC (permalink / raw)
To: Dongliang Mu
Cc: Steffen Klassert, David S. Miller, Jakub Kicinski, Dan Carpenter,
syzbot+b9cfd1cc5d57ee0a09ab, stable,
open list:NETWORKING [GENERAL],
linux-kernel
On Wed, Aug 18, 2021 at 06:39:25PM +0800, Dongliang Mu wrote:
>
> :\ Then I have no idea how this crash occurs. This crash report does
> not have any reproducer. It seems like a random crash, but I am not
> sure.
>
> If you have any patch for this crash, please let me know.
I don't have any ideas either, sorry. But my guess would be that
there is corruption somewhere else that's showing up in ipcomp.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-08-18 3:25 [PATCH] net: xfrm: assign the per_cpu_ptr pointer before return Dongliang Mu
2021-08-18 3:32 ` Herbert Xu
2021-08-18 10:39 ` Dongliang Mu
2021-08-18 12:48 ` Herbert Xu
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