bpf: sockmap, fix uninitialized variable and double-free

`e' is being freed twice.

Fix this by removing one of the kfree() calls.

Addresses-Coverity-ID: 1468983 ("Double free")

Fixes 81110384441a ("bpf: sockmap, add hash map support")

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
 kernel/bpf/sockmap.c | 1 -
 1 file changed, 1 deletion(-)

kernel/bpf/sockmap.c +0 -0

index 41b41fc..c682669 100644

There is a potential execution path in which variable err is returned without being properly initialized previously.

Fix this by initializing variable err to 0.

Addresses-Coverity-ID: 1468964 ("Uninitialized scalar variable")

Fixes e5cd3abcb31a ("bpf: sockmap, refactor sockmap routines to work

with hashmap")

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
 kernel/bpf/sockmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/bpf/sockmap.c +0 -0

index c6de139..41b41fc 100644

Quoted 24 lines · Gustavo A. R. Silva

There is a potential execution path in which variable err is returned without being properly initialized previously.

Fix this by initializing variable err to 0.

Addresses-Coverity-ID: 1468964 ("Uninitialized scalar variable")

Fixes e5cd3abcb31a ("bpf: sockmap, refactor sockmap routines to work

with hashmap")

Signed-off-by Gustavo A. R. Silva <[email protected]>

---
  kernel/bpf/sockmap.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

kernel/bpf/sockmap.c +1 -1

index c6de139..41b41fc 100644
@@ -1713,7 +1713,7 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
  	struct smap_psock_map_entry *e = NULL;
  	struct smap_psock *psock;
  	bool new = false;
-	int err;
+	int err = 0;
 

kernel/bpf/sockmap.c static int __sock_map_ctx_update_elem(struct bpf_map *map, · line 1719

Quoted 3 lines

kernel/bpf/sockmap.c +0 -0

  	/* 1. If sock map has BPF programs those will be inherited by the
  	 * sock being added. If the sock is already attached to BPF programs

Thanks for catching this and the quick fix. The path to hit this case is to add a sock to a map (without a BPF program) where the sock already has been added to another map. I don't have any tests for the case with socks in multiple maps so I'll add some to the selftests so I remember this case.

The alternative fix would be to always 'return 0' at the end of the function, but I think its probably better to init err here like above.

Acked-by John Fastabend <[email protected]>

This patchset aims to fix an uninitialized variable issue and a double-free issue in __sock_map_ctx_update_elem.

Both issues were reported by Coverity.

Thanks.

Gustavo A. R. Silva (2):
bpf: sockmap, fix uninitialized variable
bpf: sockmap, fix double-free

 kernel/bpf/sockmap.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Quoted 7 lines · Gustavo A. R. Silva

This patchset aims to fix an uninitialized variable issue and a double-free issue in __sock_map_ctx_update_elem.

Both issues were reported by Coverity.

Thanks.

Quoted 6 lines

Gustavo A. R. Silva (2):
bpf: sockmap, fix uninitialized variable
bpf: sockmap, fix double-free

  kernel/bpf/sockmap.c | 3 +--
  1 file changed, 1 insertion(+), 2 deletions(-)

Applied to bpf-next, thanks Gustavo!

P.s.: Please indicate that next time in the email subject via '[PATCH bpf-next]'.