Re: [bpf-next v3 0/2] Fix kcm + sockmap by checking psock type

On 10/20/2018 12:51 AM, Daniel Borkmann wrote:

On 10/18/2018 10:58 PM, John Fastabend wrote:

quoted

We check if the sk_user_data (the psock in skmsg) is in fact a sockmap
type to late, after we read the refcnt which is an error. This
series moves the check up before reading refcnt and also adds a test
to test_maps to test trying to add a KCM socket into a sockmap.

While reviewig this code I also found an issue with KCM and kTLS
where each uses sk_data_ready hooks and associated stream parser
breaking expectations in kcm, ktls or both. But that fix will need
to go to net.

Thanks to Eric for reporting.

v2: Fix up file +/- my scripts lost track of them
v3: return EBUSY if refcnt is zero

John Fastabend (2):
  bpf: skmsg, fix psock create on existing kcm/tls port
  bpf: test_maps add a test to catch kcm + sockmap

 include/linux/skmsg.h                     | 25 +++++++++---
 net/core/sock_map.c                       | 11 +++---
 tools/testing/selftests/bpf/Makefile      |  2 +-
 tools/testing/selftests/bpf/sockmap_kcm.c | 14 +++++++
 tools/testing/selftests/bpf/test_maps.c   | 64 ++++++++++++++++++++++++++++++-
 5 files changed, 103 insertions(+), 13 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/sockmap_kcm.c

Applied, thanks!

Fyi, I've only applied patch 1/2 for now to get the bug fixed. The patch 2/2 throws
a bunch of warnings that look like the below. Also, I think we leak kcm socket in
error paths and once we're done with testing, so would be good to close it once
unneeded. Please respin the test as a stand-alone commit, thanks:

[...]
bpf-next/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread -o /home/darkstar/trees/bpf-next-ok/tools/testing/selftests/bpf/test_maps
test_maps.c: In function ‘test_sockmap’:
test_maps.c:869:0: warning: "AF_KCM" redefined
 #define AF_KCM 41

In file included from /usr/include/sys/socket.h:38:0,
                 from test_maps.c:21:
/usr/include/bits/socket.h:133:0: note: this is the location of the previous definition
 #define AF_KCM  PF_KCM