linux-kernel - [PATCH] genetlink: Prevent memory leak when krealloc fail

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Date:   Sat, 18 Nov 2023 12:33:57 +0100
From:   Kamil Duljas <kamil.duljas@...il.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>, Jiri Pirko <jiri@...nulli.us>,
        Johannes Berg <johannes@...solutions.net>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kamil Duljas <kamil.duljas@...il.com>
Subject: [PATCH] genetlink: Prevent memory leak when krealloc fail

genl_allocate_reserve_groups() allocs new memory in while loop
but if krealloc fail, the memory allocated by kzalloc is not freed.
It seems allocated memory is unnecessary when the function
returns -ENOMEM

Signed-off-by: Kamil Duljas <kamil.duljas@...il.com>
---
 net/netlink/genetlink.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 92ef5ed2e7b0..82273d6eaea3 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -437,8 +437,10 @@ static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 			} else {
 				new_groups = krealloc(mc_groups, nlen,
 						      GFP_KERNEL);
-				if (!new_groups)
+				if (!new_groups) {
+					kfree(mc_groups);
 					return -ENOMEM;
+				}
 				mc_groups = new_groups;
 				for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
 					mc_groups[mc_groups_longs + i] = 0;
-- 
2.42.0.windows.2