* [PATCH] xtensa: simdisk: add input size check in proc_write_simdisk
@ 2025-08-29 8:30 Miaoqian Lin
2025-09-01 9:20 ` Max Filippov
0 siblings, 1 reply; 2+ messages in thread
From: Miaoqian Lin @ 2025-08-29 8:30 UTC (permalink / raw)
To: chris, jcmvbkbc, linmq006, thorsten.blum, viro; +Cc: linux-kernel, stable
A malicious user could pass an arbitrarily bad value
to memdup_user_nul(), potentially causing kernel crash.
This follows the same pattern as commit ee76746387f6
("netdevsim: prevent bad user input in nsim_dev_health_break_write()")
Fixes: b6c7e873daf7 ("xtensa: ISS: add host file-based simulated disk")
Fixes: 16e5c1fc3604 ("convert a bunch of open-coded instances of memdup_user_nul()")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
arch/xtensa/platforms/iss/simdisk.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c
index 6ed009318d24..3cafc8feddee 100644
--- a/arch/xtensa/platforms/iss/simdisk.c
+++ b/arch/xtensa/platforms/iss/simdisk.c
@@ -231,10 +231,14 @@ static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- char *tmp = memdup_user_nul(buf, count);
+ char *tmp;
struct simdisk *dev = pde_data(file_inode(file));
int err;
+ if (count == 0 || count > PAGE_SIZE)
+ return -EINVAL;
+
+ tmp = memdup_user_nul(buf, count);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] xtensa: simdisk: add input size check in proc_write_simdisk
2025-08-29 8:30 [PATCH] xtensa: simdisk: add input size check in proc_write_simdisk Miaoqian Lin
@ 2025-09-01 9:20 ` Max Filippov
0 siblings, 0 replies; 2+ messages in thread
From: Max Filippov @ 2025-09-01 9:20 UTC (permalink / raw)
To: Miaoqian Lin; +Cc: chris, thorsten.blum, viro, linux-kernel, stable
On Fri, Aug 29, 2025 at 1:30 AM Miaoqian Lin <linmq006@gmail.com> wrote:
>
> A malicious user could pass an arbitrarily bad value
> to memdup_user_nul(), potentially causing kernel crash.
>
> This follows the same pattern as commit ee76746387f6
> ("netdevsim: prevent bad user input in nsim_dev_health_break_write()")
>
> Fixes: b6c7e873daf7 ("xtensa: ISS: add host file-based simulated disk")
> Fixes: 16e5c1fc3604 ("convert a bunch of open-coded instances of memdup_user_nul()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
> arch/xtensa/platforms/iss/simdisk.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
Thanks. Applied to my xtensa tree.
-- Max
^ permalink raw reply [flat|nested] 2+ messages in thread
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2025-08-29 8:30 [PATCH] xtensa: simdisk: add input size check in proc_write_simdisk Miaoqian Lin
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