[PATCH 37/44] kdbus: Fix error path in kdbus_meta_proc_collect_cgroup()

[Sergei Zviagintsev]

Current code checks return value of task_cgroup_path(), which can be
NULL if provided buffer isn't long enough to store path there, but
alters mp->valid in case of error, producing inconsistency. Return
-ENAMETOOLONG if task_cgroup_path() fails.

Signed-off-by: Sergei Zviagintsev <sergei@xxxxxxxx>
---
 ipc/kdbus/metadata.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/ipc/kdbus/metadata.c b/ipc/kdbus/metadata.c
index b8d094d9fb56..f4f2b1af81a7 100644
--- a/ipc/kdbus/metadata.c
+++ b/ipc/kdbus/metadata.c
@@ -269,12 +269,15 @@ static int kdbus_meta_proc_collect_cgroup(struct kdbus_meta_proc *mp)
 		return -ENOMEM;
 
 	s = task_cgroup_path(current, page, PAGE_SIZE);
-	if (s) {
-		mp->cgroup = kstrdup(s, GFP_KERNEL);
-		if (!mp->cgroup) {
-			free_page((unsigned long)page);
-			return -ENOMEM;
-		}
+	if (!s) {
+		free_page((unsigned long)page);
+		return -ENAMETOOLONG;
+	}
+
+	mp->cgroup = kstrdup(s, GFP_KERNEL);
+	if (!mp->cgroup) {
+		free_page((unsigned long)page);
+		return -ENOMEM;
 	}
 
 	free_page((unsigned long)page);
-- 
1.8.3.1

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