GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-22 14:41:27 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

seccomp: add SECCOMP_RET_ERRNO

Browse source 
This change adds the SECCOMP_RET_ERRNO as a valid return value from a
seccomp filter.  Additionally, it makes the first use of the lower
16-bits for storing a filter-supplied errno.  16-bits is more than
enough for the errno-base.h calls.

Returning errors instead of immediately terminating processes that
violate seccomp policy allow for broader use of this functionality
for kernel attack surface reduction.  For example, a linux container
could maintain a whitelist of pre-existing system calls but drop
all new ones with errnos.  This would keep a logically static attack
surface while providing errnos that may allow for graceful failure
without the downside of do_exit() on a bad call.

This change also changes the signature of __secure_computing.  It
appears the only direct caller is the arm entry code and it clobbers
any possible return value (register) immediately.

Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Eric Paris <eparis@redhat.com>

v18: - fix up comments and rebase
     - fix bad var name which was fixed in later revs
     - remove _int() and just change the __secure_computing signature
v16-v17: ...
v15: - use audit_seccomp and add a skip label. (eparis@redhat.com)
     - clean up and pad out return codes (indan@nul.nu)
v14: - no change/rebase
v13: - rebase on to 88ebdda615
v12: - move to WARN_ON if filter is NULL
       (oleg@redhat.com, luto@mit.edu, keescook@chromium.org)
     - return immediately for filter==NULL (keescook@chromium.org)
     - change evaluation to only compare the ACTION so that layered
       errnos don't result in the lowest one being returned.
       (keeschook@chromium.org)
v11: - check for NULL filter (keescook@chromium.org)
v10: - change loaders to fn
 v9: - n/a
 v8: - update Kconfig to note new need for syscall_set_return_value.
     - reordered such that TRAP behavior follows on later.
     - made the for loop a little less indent-y
 v7: - introduced
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Will Drewry 2012-04-12 16:47:59 -05:00 • committed by James Morris
parent 3dc1c1b2d2
commit acf3b2c71e
3 changed files with 42 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

10
include/linux/seccomp.h
View file

@ -12,13 +12,14 @@
/*
* All BPF programs must return a 32-bit value.
* The bottom 16-bits are reserved for future use.
* The bottom 16-bits are for optional return data.
* The upper 16-bits are ordered from least permissive values to most.
*
* The ordering ensures that a min_t() over composed return values always
* selects the least permissive choice.
*/
#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
/* Masks for the return value sections. */
@ -64,11 +65,12 @@ struct seccomp {
struct seccomp_filter *filter;
};
extern void __secure_computing(int);
static inline void secure_computing(int this_syscall)
extern int __secure_computing(int);
static inline int secure_computing(int this_syscall)
{
if (unlikely(test_thread_flag(TIF_SECCOMP)))
__secure_computing(this_syscall);
return __secure_computing(this_syscall);
return 0;
}
extern long prctl_get_seccomp(void);