[PATCH v5 4/8] LSM: lsm_get_self_attr syscall for LSM self attributes

[Casey Schaufler]

On 2/14/2023 9:41 AM, Mickaël Salaün wrote:
>
> On 09/01/2023 19:07, Casey Schaufler wrote:
>> Create a system call lsm_get_self_attr() to provide the security
>> module maintained attributes of the current process. Historically
>> these attributes have been exposed to user space via entries in
>> procfs under /proc/self/attr.
>>
>> Attributes are provided as a collection of lsm_ctx structures
>> which are placed into a user supplied buffer. Each structure
>> identifys the size of the attribute, and the attribute value.
>> The format of the attribute value is defined by the security
>> module, but will always be \0 terminated. The ctx_len value
>> will always be strlen(ctx)+1.
>>
>>          ---------------------------
>>          | __u32 id                |
>>          ---------------------------
>>          | __u64 flags             |
>>          ---------------------------
>>          | __kernel_size_t ctx_len |
>>          ---------------------------
>>          | __u8 ctx[ctx_len]       |
>>          ---------------------------
>>          | __u32 id                |
>>          ---------------------------
>>          | __u64 flags             |
>>          ---------------------------
>>          | __kernel_size_t ctx_len |
>>          ---------------------------
>>          | __u8 ctx[ctx_len]       |
>>          ---------------------------
>>
>> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
>> ---
>>   Documentation/userspace-api/lsm.rst |   9 ++
>>   include/linux/syscalls.h            |   3 +
>>   include/uapi/linux/lsm.h            |  21 ++++
>>   kernel/sys_ni.c                     |   3 +
>>   security/Makefile                   |   1 +
>>   security/lsm_syscalls.c             | 182 ++++++++++++++++++++++++++++
>>   6 files changed, 219 insertions(+)
>>   create mode 100644 security/lsm_syscalls.c
>
> For new files (e.g. lsm_syscalls.c), it would be nice to auto-format
> them with clang-format. It helps maintenance by keeping a consistent
> style across commits, which should also help backports, and it avoids
> nitpicking on style issues.

Good idea.