From: Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>,
Nick Child <nnac123@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Scott Cheloha <cheloha@linux.ibm.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 7/8] powerpc/rtas: warn on unsafe argument to rtas_call_unlocked()
Date: Mon, 06 Mar 2023 15:33:46 -0600 [thread overview]
Message-ID: <20230220-rtas-queue-for-6-4-v1-7-010e4416f13f@linux.ibm.com> (raw)
In-Reply-To: <20230220-rtas-queue-for-6-4-v1-0-010e4416f13f@linux.ibm.com>
From: Nathan Lynch <nathanl@linux.ibm.com>
Any caller of rtas_call_unlocked() must provide an rtas_args parameter
block distinct from the core rtas_args buffer used by the rtas_call()
path. It's an unlikely error to make, but the potential consequences
are grim, and it's trivial to check.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
arch/powerpc/kernel/rtas.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 633c925164e7..47a2aa43d7d4 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1042,6 +1042,13 @@ void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
{
va_list list;
+ /*
+ * Callers must not use rtas_args; otherwise they risk
+ * corrupting the state of the rtas_call() path, which is
+ * serialized by rtas_lock.
+ */
+ WARN_ON(args == &rtas_args);
+
va_start(list, nret);
va_rtas_call(args, token, nargs, nret, list);
va_end(list);
--
2.39.1
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Lynch <nathanl@linux.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev@lists.ozlabs.org,
Tyrel Datwyler <tyreld@linux.ibm.com>,
Scott Cheloha <cheloha@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Nick Child <nnac123@linux.ibm.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
Nathan Lynch <nathanl@linux.ibm.com>
Subject: [PATCH 7/8] powerpc/rtas: warn on unsafe argument to rtas_call_unlocked()
Date: Mon, 06 Mar 2023 15:33:46 -0600 [thread overview]
Message-ID: <20230220-rtas-queue-for-6-4-v1-7-010e4416f13f@linux.ibm.com> (raw)
In-Reply-To: <20230220-rtas-queue-for-6-4-v1-0-010e4416f13f@linux.ibm.com>
Any caller of rtas_call_unlocked() must provide an rtas_args parameter
block distinct from the core rtas_args buffer used by the rtas_call()
path. It's an unlikely error to make, but the potential consequences
are grim, and it's trivial to check.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
arch/powerpc/kernel/rtas.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 633c925164e7..47a2aa43d7d4 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1042,6 +1042,13 @@ void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
{
va_list list;
+ /*
+ * Callers must not use rtas_args; otherwise they risk
+ * corrupting the state of the rtas_call() path, which is
+ * serialized by rtas_lock.
+ */
+ WARN_ON(args == &rtas_args);
+
va_start(list, nret);
va_rtas_call(args, token, nargs, nret, list);
va_end(list);
--
2.39.1
next prev parent reply other threads:[~2023-03-06 21:36 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 21:33 [PATCH 0/8] RTAS changes for 6.4 Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-06 21:33 ` [PATCH 1/8] powerpc/rtas: ensure 8-byte alignment for struct rtas_args Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:00 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 2/8] powerpc/rtas: use memmove for potentially overlapping buffer copy Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:09 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 3/8] powerpc/rtas: rtas_call_unlocked() kerneldoc Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 4:15 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 4/8] powerpc/rtas: fix miswording in rtas_function kerneldoc Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 0:17 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 5/8] powerpc/rtas: rename va_rtas_call_unlocked() to va_rtas_call() Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:17 ` Andrew Donnellan
2023-03-23 16:11 ` Nathan Lynch
2023-03-29 12:24 ` Michael Ellerman
2023-03-06 21:33 ` [PATCH 6/8] powerpc/rtas: lockdep annotations Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 6:01 ` Andrew Donnellan
2023-03-06 21:33 ` Nathan Lynch via B4 Relay [this message]
2023-03-06 21:33 ` [PATCH 7/8] powerpc/rtas: warn on unsafe argument to rtas_call_unlocked() Nathan Lynch
2023-03-23 4:25 ` Andrew Donnellan
2023-03-23 12:17 ` Nathan Lynch
2023-03-24 0:56 ` Nathan Lynch
2023-03-29 12:20 ` Michael Ellerman
2023-03-29 16:23 ` Nathan Lynch
2023-03-06 21:33 ` [PATCH 8/8] powerpc/rtas: consume retry statuses in sys_rtas() Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 6:26 ` Andrew Donnellan
2023-03-23 19:39 ` Nathan Lynch
2023-03-23 9:44 ` Michael Ellerman
2023-03-23 13:40 ` Nathan Lynch
2024-01-25 15:55 ` Christophe Leroy
2024-01-25 16:33 ` Nathan Lynch
2024-01-25 16:46 ` Christophe Leroy
2024-01-25 17:23 ` Nathan Lynch
2023-04-06 1:09 ` (subset) [PATCH 0/8] RTAS changes for 6.4 Michael Ellerman
2023-04-26 12:12 ` Michael Ellerman
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