bpf: add security_file_post_open() LSM hook to sleepable_lsm_hooks

Commit Message

Matt Bobrowski June 18, 2024, 7:29 p.m. UTC

The new generic LSM hook security_file_post_open() was recently added
to the LSM framework in commit 8f46ff5767b0b ("security: Introduce
file_post_open hook"). Let's proactively add this generic LSM hook to
the sleepable_lsm_hooks BTF ID set, because I can't see there being
any strong reasons not to, and it's only a matter of time before
someone else comes around and asks for it to be there.

security_file_post_open() is inherently sleepable as it's purposely
situated in the kernel that allows LSMs to directly read out the
contents of the backing file if need be. Additionally, it's called
directly after securuty_file_open(), and that LSM hook in itself
already exists in the sleepable_lsm_hooks BTF ID set.

Signed-off-by: Matt Bobrowski <[e-mail]>
---
 kernel/bpf/bpf_lsm.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Paul Moore June 18, 2024, 7:44 p.m. UTC | #1

On Tue, Jun 18, 2024 at 3:29 PM Matt Bobrowski <[e-mail]> wrote:
>
> The new generic LSM hook security_file_post_open() was recently added
> to the LSM framework in commit 8f46ff5767b0b ("security: Introduce
> file_post_open hook"). Let's proactively add this generic LSM hook to
> the sleepable_lsm_hooks BTF ID set, because I can't see there being
> any strong reasons not to, and it's only a matter of time before
> someone else comes around and asks for it to be there.
>
> security_file_post_open() is inherently sleepable as it's purposely
> situated in the kernel that allows LSMs to directly read out the
> contents of the backing file if need be. Additionally, it's called
> directly after securuty_file_open(), and that LSM hook in itself

*cough*

"security_file_open()"

*cough*

> already exists in the sleepable_lsm_hooks BTF ID set.
>
> Signed-off-by: Matt Bobrowski <[e-mail]>
> ---
>  kernel/bpf/bpf_lsm.c | 1 +
>  1 file changed, 1 insertion(+)

Daniel Borkmann June 21, 2024, 5:58 p.m. UTC | #2

On 6/18/24 9:44 PM, Paul Moore wrote:
> On Tue, Jun 18, 2024 at 3:29 PM Matt Bobrowski <[e-mail]> wrote:
>>
>> The new generic LSM hook security_file_post_open() was recently added
>> to the LSM framework in commit 8f46ff5767b0b ("security: Introduce
>> file_post_open hook"). Let's proactively add this generic LSM hook to
>> the sleepable_lsm_hooks BTF ID set, because I can't see there being
>> any strong reasons not to, and it's only a matter of time before
>> someone else comes around and asks for it to be there.
>>
>> security_file_post_open() is inherently sleepable as it's purposely
>> situated in the kernel that allows LSMs to directly read out the
>> contents of the backing file if need be. Additionally, it's called
>> directly after securuty_file_open(), and that LSM hook in itself
> 
> *cough*
> 
> "security_file_open()"

Fixed up while applying, thanks!

[e-mail] June 21, 2024, 6 p.m. UTC | #3

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <[e-mail]>:

On Tue, 18 Jun 2024 19:29:22 +0000 you wrote:
> The new generic LSM hook security_file_post_open() was recently added
> to the LSM framework in commit 8f46ff5767b0b ("security: Introduce
> file_post_open hook"). Let's proactively add this generic LSM hook to
> the sleepable_lsm_hooks BTF ID set, because I can't see there being
> any strong reasons not to, and it's only a matter of time before
> someone else comes around and asks for it to be there.
> 
> [...]

Here is the summary with links:
  - bpf: add security_file_post_open() LSM hook to sleepable_lsm_hooks
    https://git.kernel.org/bpf/bpf-next/c/6ddf3a9abd9f

You are awesome, thank you!

Patch

diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index 68240c3c6e7d..08a338e1f231 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -280,6 +280,7 @@  BTF_ID(func, bpf_lsm_cred_prepare)
 BTF_ID(func, bpf_lsm_file_ioctl)
 BTF_ID(func, bpf_lsm_file_lock)
 BTF_ID(func, bpf_lsm_file_open)
+BTF_ID(func, bpf_lsm_file_post_open)
 BTF_ID(func, bpf_lsm_file_receive)
 
 BTF_ID(func, bpf_lsm_inode_create)