From 23d67a54857a768acdb0804cdd6037c324a50ecd Mon Sep 17 00:00:00 2001 From: Gabriel Krisman Bertazi Date: Mon, 16 Nov 2020 12:42:00 -0500 Subject: seccomp: Migrate to use SYSCALL_WORK flag On architectures using the generic syscall entry code the architecture independent syscall work is moved to flags in thread_info::syscall_work. This removes architecture dependencies and frees up TIF bits. Define SYSCALL_WORK_SECCOMP, use it in the generic entry code and convert the code which uses the TIF specific helper functions to use the new *_syscall_work() helpers which either resolve to the new mode for users of the generic entry code or to the TIF based functions for the other architectures. Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Thomas Gleixner Reviewed-by: Andy Lutomirski Link: https://lore.kernel.org/r/20201116174206.2639648-5-krisman@collabora.com --- include/linux/seccomp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/seccomp.h') diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 02aef2844c38..47763f3999f7 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -42,7 +42,7 @@ struct seccomp { extern int __secure_computing(const struct seccomp_data *sd); static inline int secure_computing(void) { - if (unlikely(test_thread_flag(TIF_SECCOMP))) + if (unlikely(test_syscall_work(SECCOMP))) return __secure_computing(NULL); return 0; } -- cgit From 0d8315dddd2899f519fe1ca3d4d5cdaf44ea421e Mon Sep 17 00:00:00 2001 From: YiFei Zhu Date: Wed, 11 Nov 2020 07:33:54 -0600 Subject: seccomp/cache: Report cache data through /proc/pid/seccomp_cache Currently the kernel does not provide an infrastructure to translate architecture numbers to a human-readable name. Translating syscall numbers to syscall names is possible through FTRACE_SYSCALL infrastructure but it does not provide support for compat syscalls. This will create a file for each PID as /proc/pid/seccomp_cache. The file will be empty when no seccomp filters are loaded, or be in the format of: where ALLOW means the cache is guaranteed to allow the syscall, and filter means the cache will pass the syscall to the BPF filter. For the docker default profile on x86_64 it looks like: x86_64 0 ALLOW x86_64 1 ALLOW x86_64 2 ALLOW x86_64 3 ALLOW [...] x86_64 132 ALLOW x86_64 133 ALLOW x86_64 134 FILTER x86_64 135 FILTER x86_64 136 FILTER x86_64 137 ALLOW x86_64 138 ALLOW x86_64 139 FILTER x86_64 140 ALLOW x86_64 141 ALLOW [...] This file is guarded by CONFIG_SECCOMP_CACHE_DEBUG with a default of N because I think certain users of seccomp might not want the application to know which syscalls are definitely usable. For the same reason, it is also guarded by CAP_SYS_ADMIN. Suggested-by: Jann Horn Link: https://lore.kernel.org/lkml/CAG48ez3Ofqp4crXGksLmZY6=fGrF_tWyUCg7PBkAetvbbOPeOA@mail.gmail.com/ Signed-off-by: YiFei Zhu Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/94e663fa53136f5a11f432c661794d1ee7060779.1605101222.git.yifeifz2@illinois.edu --- include/linux/seccomp.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/seccomp.h') diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 02aef2844c38..76963ec4641a 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -121,4 +121,11 @@ static inline long seccomp_get_metadata(struct task_struct *task, return -EINVAL; } #endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */ + +#ifdef CONFIG_SECCOMP_CACHE_DEBUG +struct seq_file; + +int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *task); +#endif #endif /* _LINUX_SECCOMP_H */ -- cgit