[PATCH 7/7] sysvipc_find_ipc should increase position index

From: Vasily Averin
Date: Fri Jan 24 2020 - 02:03:49 EST


if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
---
ipc/util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ipc/util.c b/ipc/util.c
index 915eacb..7a3ab2e 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -764,13 +764,13 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
total++;
}

+ *new_pos = pos + 1;
if (total >= ids->in_use)
return NULL;

for (; pos < ipc_mni; pos++) {
ipc = idr_find(&ids->ipcs_idr, pos);
if (ipc != NULL) {
- *new_pos = pos + 1;
rcu_read_lock();
ipc_lock_object(ipc);
return ipc;
--
1.8.3.1