Re: [PATCH linux-next] selinux: avc: use sysfs_emit() instead of scnprintf()

[Stephen Smalley]

On Sat, Mar 15, 2025 at 2:12 AM <xie.ludan@xxxxxxxxxx> wrote:
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> From: XieLudan <xie.ludan@xxxxxxxxxx>
>
>
> Follow the advice in Documentation/filesystems/sysfs.rst:
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> show() should only use sysfs_emit() or sysfs_emit_at() when formatting
>
> the value to be returned to user space.
>
>
> Signed-off-by: XieLudan <xie.ludan@xxxxxxxxxx>

NAK.
Despite being mounted under /sys, selinuxfs is its own pseudo
filesystem and thus shouldn't use sysfs functions.

>
> ---
>
>  security/selinux/avc.c | 2 +-
>
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
>
> diff --git a/security/selinux/avc.c b/security/selinux/avc.c
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> index 4b4837a20225..007bd94975c0 100644
>
> --- a/security/selinux/avc.c
>
> +++ b/security/selinux/avc.c
>
> @@ -164,7 +164,7 @@ int avc_get_hash_stats(char *page)
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>
>
>   rcu_read_unlock();
>
>
>
> - return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
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> + return sysfs_emit(page, "entries: %d\nbuckets used: %d/%d\n"
>
>   "longest chain: %d\n",
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>   atomic_read(&selinux_avc.avc_cache.active_nodes),
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>   slots_used, AVC_CACHE_SLOTS, max_chain_len);
>
> --
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> 2.25.1
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>
>
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>