| Message ID | 20210818032554.283428-1-mudongliangabcd@gmail.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: xfrm: assign the per_cpu_ptr pointer before return | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | success | CCed 5 of 5 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 10 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
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,
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
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,
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;
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(-)