This is a note to let you know that I've just added the patch titled
powerpc/powernv: Fix fortify source warnings in opal-prd.c
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-powernv-fix-fortify-source-warnings-in-opal-prd.c.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From feea65a338e52297b68ceb688eaf0ffc50310a83 Mon Sep 17 00:00:00 2001
From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Date: Tue, 22 Aug 2023 00:28:19 +1000
Subject: powerpc/powernv: Fix fortify source warnings in opal-prd.c
From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
commit feea65a338e52297b68ceb688eaf0ffc50310a83 upstream.
As reported by Mahesh & Aneesh, opal_prd_msg_notifier() triggers a
FORTIFY_SOURCE warning:
memcpy: detected field-spanning write (size 32) of single field "&item->msg" at arch/powerpc/platforms/powernv/opal-prd.c:355 (size 4)
WARNING: CPU: 9 PID: 660 at arch/powerpc/platforms/powernv/opal-prd.c:355 opal_prd_msg_notifier+0x174/0x188 [opal_prd]
NIP opal_prd_msg_notifier+0x174/0x188 [opal_prd]
LR opal_prd_msg_notifier+0x170/0x188 [opal_prd]
Call Trace:
opal_prd_msg_notifier+0x170/0x188 [opal_prd] (unreliable)
notifier_call_chain+0xc0/0x1b0
atomic_notifier_call_chain+0x2c/0x40
opal_message_notify+0xf4/0x2c0
This happens because the copy is targeting item->msg, which is only 4
bytes in size, even though the enclosing item was allocated with extra
space following the msg.
To fix the warning define struct opal_prd_msg with a union of the header
and a flex array, and have the memcpy target the flex array.
Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Reported-by: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxx>
Tested-by: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxx>
Reviewed-by: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20230821142820.497107-1-mpe@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/powernv/opal-prd.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/arch/powerpc/platforms/powernv/opal-prd.c
+++ b/arch/powerpc/platforms/powernv/opal-prd.c
@@ -24,13 +24,20 @@
#include <linux/uaccess.h>
+struct opal_prd_msg {
+ union {
+ struct opal_prd_msg_header header;
+ DECLARE_FLEX_ARRAY(u8, data);
+ };
+};
+
/*
* The msg member must be at the end of the struct, as it's followed by the
* message data.
*/
struct opal_prd_msg_queue_item {
- struct list_head list;
- struct opal_prd_msg_header msg;
+ struct list_head list;
+ struct opal_prd_msg msg;
};
static struct device_node *prd_node;
@@ -159,7 +166,7 @@ static ssize_t opal_prd_read(struct file
int rc;
/* we need at least a header's worth of data */
- if (count < sizeof(item->msg))
+ if (count < sizeof(item->msg.header))
return -EINVAL;
if (*ppos)
@@ -189,7 +196,7 @@ static ssize_t opal_prd_read(struct file
return -EINTR;
}
- size = be16_to_cpu(item->msg.size);
+ size = be16_to_cpu(item->msg.header.size);
if (size > count) {
err = -EINVAL;
goto err_requeue;
@@ -355,7 +362,7 @@ static int opal_prd_msg_notifier(struct
if (!item)
return -ENOMEM;
- memcpy(&item->msg, msg->params, msg_size);
+ memcpy(&item->msg.data, msg->params, msg_size);
spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
list_add_tail(&item->list, &opal_prd_msg_queue);
Patches currently in stable-queue which might be from mpe@xxxxxxxxxxxxxx are
queue-5.10/powerpc-perf-fix-disabling-bhrb-and-instruction-sampling.patch
queue-5.10/powerpc-powernv-fix-fortify-source-warnings-in-opal-prd.c.patch
