1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
|
From b1233fb86422dfce8ab90b4a67608cef622c8c55 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 18 Jun 2025 14:08:44 +0000
Subject: net: atm: fix /proc/net/atm/lec handling
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit d03b79f459c7935cff830d98373474f440bd03ae ]
/proc/net/atm/lec must ensure safety against dev_lec[] changes.
It appears it had dev_put() calls without prior dev_hold(),
leading to imbalance and UAF.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Francois Romieu <romieu@fr.zoreil.com> # Minor atm contributor
Link: https://patch.msgid.link/20250618140844.1686882-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/atm/lec.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/atm/lec.c b/net/atm/lec.c
index 09c042e1e4696..42e8047c65105 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -909,7 +909,6 @@ static void *lec_itf_walk(struct lec_state *state, loff_t *l)
v = (dev && netdev_priv(dev)) ?
lec_priv_walk(state, l, netdev_priv(dev)) : NULL;
if (!v && dev) {
- dev_put(dev);
/* Partial state reset for the next time we get called */
dev = NULL;
}
@@ -933,6 +932,7 @@ static void *lec_seq_start(struct seq_file *seq, loff_t *pos)
{
struct lec_state *state = seq->private;
+ mutex_lock(&lec_mutex);
state->itf = 0;
state->dev = NULL;
state->locked = NULL;
@@ -950,8 +950,9 @@ static void lec_seq_stop(struct seq_file *seq, void *v)
if (state->dev) {
spin_unlock_irqrestore(&state->locked->lec_arp_lock,
state->flags);
- dev_put(state->dev);
+ state->dev = NULL;
}
+ mutex_unlock(&lec_mutex);
}
static void *lec_seq_next(struct seq_file *seq, void *v, loff_t *pos)
--
2.39.5
|
