* [PATCH] fs/orangefs: Replace kzalloc + copy_from_user with memdup_user_nul
@ 2025-09-18 15:08 Thorsten Blum
2025-09-24 13:55 ` Mike Marshall
0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2025-09-18 15:08 UTC (permalink / raw)
To: Mike Marshall, Martin Brandenburg; +Cc: Thorsten Blum, devel, linux-kernel
Replace kzalloc() followed by copy_from_user() with memdup_user_nul() to
simplify and improve orangefs_debug_write(). Allocate only 'count' bytes
instead of the maximum size ORANGEFS_MAX_DEBUG_STRING_LEN, and set 'buf'
to NULL to ensure kfree(buf) still works.
No functional changes intended.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
fs/orangefs/orangefs-debugfs.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c
index 1c375fb65018..79267b3419f2 100644
--- a/fs/orangefs/orangefs-debugfs.c
+++ b/fs/orangefs/orangefs-debugfs.c
@@ -440,14 +440,13 @@ static ssize_t orangefs_debug_write(struct file *file,
count = ORANGEFS_MAX_DEBUG_STRING_LEN;
}
- buf = kzalloc(ORANGEFS_MAX_DEBUG_STRING_LEN, GFP_KERNEL);
- if (!buf)
- goto out;
-
- if (copy_from_user(buf, ubuf, count - 1)) {
+ buf = memdup_user_nul(ubuf, count - 1);
+ if (IS_ERR(buf)) {
gossip_debug(GOSSIP_DEBUGFS_DEBUG,
- "%s: copy_from_user failed!\n",
+ "%s: memdup_user_nul failed!\n",
__func__);
+ rc = PTR_ERR(buf);
+ buf = NULL;
goto out;
}
--
2.51.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] fs/orangefs: Replace kzalloc + copy_from_user with memdup_user_nul
2025-09-18 15:08 [PATCH] fs/orangefs: Replace kzalloc + copy_from_user with memdup_user_nul Thorsten Blum
@ 2025-09-24 13:55 ` Mike Marshall
0 siblings, 0 replies; 2+ messages in thread
From: Mike Marshall @ 2025-09-24 13:55 UTC (permalink / raw)
To: Thorsten Blum; +Cc: Martin Brandenburg, devel, linux-kernel, Mike Marshall
Thanks, that looks better in several ways. I ran it through xfstests,
and have added it to my linux-next tree...
-Mike
On Thu, Sep 18, 2025 at 11:08 AM Thorsten Blum <thorsten.blum@linux.dev> wrote:
>
> Replace kzalloc() followed by copy_from_user() with memdup_user_nul() to
> simplify and improve orangefs_debug_write(). Allocate only 'count' bytes
> instead of the maximum size ORANGEFS_MAX_DEBUG_STRING_LEN, and set 'buf'
> to NULL to ensure kfree(buf) still works.
>
> No functional changes intended.
>
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> fs/orangefs/orangefs-debugfs.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/fs/orangefs/orangefs-debugfs.c b/fs/orangefs/orangefs-debugfs.c
> index 1c375fb65018..79267b3419f2 100644
> --- a/fs/orangefs/orangefs-debugfs.c
> +++ b/fs/orangefs/orangefs-debugfs.c
> @@ -440,14 +440,13 @@ static ssize_t orangefs_debug_write(struct file *file,
> count = ORANGEFS_MAX_DEBUG_STRING_LEN;
> }
>
> - buf = kzalloc(ORANGEFS_MAX_DEBUG_STRING_LEN, GFP_KERNEL);
> - if (!buf)
> - goto out;
> -
> - if (copy_from_user(buf, ubuf, count - 1)) {
> + buf = memdup_user_nul(ubuf, count - 1);
> + if (IS_ERR(buf)) {
> gossip_debug(GOSSIP_DEBUGFS_DEBUG,
> - "%s: copy_from_user failed!\n",
> + "%s: memdup_user_nul failed!\n",
> __func__);
> + rc = PTR_ERR(buf);
> + buf = NULL;
> goto out;
> }
>
> --
> 2.51.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2025-09-18 15:08 [PATCH] fs/orangefs: Replace kzalloc + copy_from_user with memdup_user_nul Thorsten Blum
2025-09-24 13:55 ` Mike Marshall
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