On Fri 11-10-24 13:37:22, Song Liu wrote:
> Currently, fsnotify_open_perm() is called from security_file_open(). This
> is not right for CONFIG_SECURITY=n and CONFIG_FSNOTIFY=y case, as
> security_file_open() in this combination will be a no-op and not call
> fsnotify_open_perm(). Fix this by calling fsnotify_open_perm() directly.
>
> Signed-off-by: Song Liu <song@xxxxxxxxxx>
>
> ---
>
> PS: I didn't included a Fixes tag. This issue was probably introduced 15
> years ago in [1]. If we want to back port this to stable, we will need
> another version for older kernel because of [2].
Well, this is not a problem because CONFIG_FANOTIFY_ACCESS_PERMISSIONS has
"depends on SECURITY". So fsnotify_open_perm() can have anything to do only
if CONFIG_SECURITY is enabled. That being said I agree it makes sense to
decouple security & fsnotify because there's no significant benefit and
only confusion. So I like the patch but please update the changelog and
also finish the split as Amir suggests.
Honza
> [1] c4ec54b40d33 ("fsnotify: new fsnotify hooks and events types for access decisions")
> [2] 36e28c42187c ("fsnotify: split fsnotify_perm() into two hooks")
> ---
> fs/open.c | 4 ++++
> security/security.c | 9 +--------
> 2 files changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/fs/open.c b/fs/open.c
> index acaeb3e25c88..6c4950f19cfb 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -946,6 +946,10 @@ static int do_dentry_open(struct file *f,
> if (error)
> goto cleanup_all;
>
> + error = fsnotify_open_perm(f);
> + if (error)
> + goto cleanup_all;
> +
> error = break_lease(file_inode(f), f->f_flags);
> if (error)
> goto cleanup_all;
> diff --git a/security/security.c b/security/security.c
> index 6875eb4a59fc..a72cc62c0a07 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -19,7 +19,6 @@
> #include <linux/kernel.h>
> #include <linux/kernel_read_file.h>
> #include <linux/lsm_hooks.h>
> -#include <linux/fsnotify.h>
> #include <linux/mman.h>
> #include <linux/mount.h>
> #include <linux/personality.h>
> @@ -3102,13 +3101,7 @@ int security_file_receive(struct file *file)
> */
> int security_file_open(struct file *file)
> {
> - int ret;
> -
> - ret = call_int_hook(file_open, file);
> - if (ret)
> - return ret;
> -
> - return fsnotify_open_perm(file);
> + return call_int_hook(file_open, file);
> }
>
> /**
> --
> 2.43.5
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
