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author | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-21 17:28:19 +0300 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-24 15:33:04 +0300 |
commit | feea65a338e52297b68ceb688eaf0ffc50310a83 (patch) | |
tree | d5b3ddfb3021a04af4b67e309f78b79970a6f441 /arch/powerpc/platforms/powernv/opal-prd.c | |
parent | c265735ff5b1f13272e2bfb196f5c55f9b3c9bac (diff) | |
download | linux-feea65a338e52297b68ceb688eaf0ffc50310a83.tar.xz |
powerpc/powernv: Fix fortify source warnings in opal-prd.c
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@linux.ibm.com>
Reported-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Tested-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230821142820.497107-1-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc/platforms/powernv/opal-prd.c')
-rw-r--r-- | arch/powerpc/platforms/powernv/opal-prd.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-prd.c b/arch/powerpc/platforms/powernv/opal-prd.c index 113bdb151f68..40e26e9f318f 100644 --- 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; @@ -156,7 +163,7 @@ static ssize_t opal_prd_read(struct file *file, char __user *buf, 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) @@ -186,7 +193,7 @@ static ssize_t opal_prd_read(struct file *file, char __user *buf, 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; @@ -352,7 +359,7 @@ static int opal_prd_msg_notifier(struct notifier_block *nb, 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); |