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authorYiFei Zhu <yifeifz2@illinois.edu>2020-11-11 16:33:54 +0300
committerKees Cook <keescook@chromium.org>2020-11-20 22:16:35 +0300
commit0d8315dddd2899f519fe1ca3d4d5cdaf44ea421e (patch)
tree5e761960d24bde7cb22cbb01ec797751f1823a15 /fs/proc
parent445247b02342a05b7d528bba6d85d2d418875b69 (diff)
downloadlinux-0d8315dddd2899f519fe1ca3d4d5cdaf44ea421e.tar.xz
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: <arch name> <decimal syscall number> <ALLOW | FILTER> 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 <jannh@google.com> Link: https://lore.kernel.org/lkml/CAG48ez3Ofqp4crXGksLmZY6=fGrF_tWyUCg7PBkAetvbbOPeOA@mail.gmail.com/ Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/94e663fa53136f5a11f432c661794d1ee7060779.1605101222.git.yifeifz2@illinois.edu
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index b362523a9829..8a7d682ba881 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3263,6 +3263,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_PROC_PID_ARCH_STATUS
ONE("arch_status", S_IRUGO, proc_pid_arch_status),
#endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+ ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
};
static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
@@ -3592,6 +3595,9 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_PROC_PID_ARCH_STATUS
ONE("arch_status", S_IRUGO, proc_pid_arch_status),
#endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+ ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
};
static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)