From: Alexander Kapshuk <alexander.kapshuk@gmail.com>
To: asmadeus@codewreck.org
Cc: lucho@ionkov.net, ericvh@gmail.com, davem@davemloft.net,
kuba@kernel.org, v9fs-developer@lists.sourceforge.net,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
alexander.kapshuk@gmail.com
Subject: [PATCH] net/9p: Validate current->sighand in client.c
Date: Sun, 21 Jun 2020 16:53:12 +0300 [thread overview]
Message-ID: <20200621135312.78201-1-alexander.kapshuk@gmail.com> (raw)
In-Reply-To: <20200621084512.GA720@nautica>
Fix rcu not being dereferenced cleanly by using the task
helpers (un)lock_task_sighand instead of spin_lock_irqsave and
spin_unlock_irqrestore to ensure current->sighand is a valid pointer as
suggested in the email referenced below.
Signed-off-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Link: https://lore.kernel.org/lkml/20200618190807.GA20699@nautica/
---
net/9p/client.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index fc1f3635e5dd..15f16f2baa8f 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -787,9 +787,14 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
}
recalc_sigpending:
if (sigpending) {
- spin_lock_irqsave(¤t->sighand->siglock, flags);
+ if (!lock_task_sighand(current, &flags)) {
+ pr_warn("%s (%d): current->sighand==NULL in recalc_sigpending\n",
+ __func__, task_pid_nr(current));
+ err = -ESRCH;
+ goto reterr;
+ }
recalc_sigpending();
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ unlock_task_sighand(current, &flags);
}
if (err < 0)
goto reterr;
@@ -869,9 +874,14 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
}
recalc_sigpending:
if (sigpending) {
- spin_lock_irqsave(¤t->sighand->siglock, flags);
+ if (!lock_task_sighand(current, &flags)) {
+ pr_warn("%s (%d): current->sighand==NULL in recalc_sigpending\n",
+ __func__, task_pid_nr(current));
+ err = -ESRCH;
+ goto reterr;
+ }
recalc_sigpending();
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
+ unlock_task_sighand(current, &flags);
}
if (err < 0)
goto reterr;
--
2.27.0
next prev parent reply other threads:[~2020-06-21 13:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-18 18:33 [PATCH] net/9p: Fix sparse rcu warnings in client.c Alexander Kapshuk
2020-06-18 19:08 ` Dominique Martinet
2020-06-18 19:40 ` Alexander Kapshuk
2020-06-20 20:14 ` [PATCH] net/9p: Validate current->sighand " Alexander Kapshuk
2020-06-21 8:45 ` Dominique Martinet
2020-06-21 10:30 ` Alexander Kapshuk
2020-06-21 10:56 ` Dominique Martinet
2020-06-21 11:19 ` Alexander Kapshuk
2020-06-21 13:53 ` Alexander Kapshuk [this message]
2020-06-21 13:56 ` Dominique Martinet
2020-06-21 13:58 ` Alexander Kapshuk
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