From 9a71b1122c6e49dd9227f82b2f53837c7ea13019 Mon Sep 17 00:00:00 2001 From: Jay Faulkner Date: Fri, 20 Feb 2015 21:59:47 +0000 Subject: [PATCH] nspawn: Map all seccomp filters to capabilities This change makes it so all seccomp filters are mapped to the appropriate capability and are only added if that capability was not requested when running the container. This unbreaks the remaining use cases broken by the addition of seccomp filters without respecting requested capabilities. Co-Authored-By: Clif Houck [zj: - adapt to our coding style, make struct anonymous] --- src/nspawn/nspawn.c | 44 +++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 27 deletions(-) diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 8ce5fbeb6..8833704ab 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -2567,19 +2567,19 @@ static int setup_ipvlan(pid_t pid) { static int setup_seccomp(void) { #ifdef HAVE_SECCOMP - static const int blacklist[] = { - SCMP_SYS(kexec_load), - SCMP_SYS(open_by_handle_at), - SCMP_SYS(iopl), - SCMP_SYS(ioperm), - SCMP_SYS(swapon), - SCMP_SYS(swapoff), - }; - - static const int kmod_blacklist[] = { - SCMP_SYS(init_module), - SCMP_SYS(finit_module), - SCMP_SYS(delete_module), + static const struct { + uint64_t capability; + int syscall_num; + } blacklist[] = { + { CAP_SYS_RAWIO, SCMP_SYS(iopl)}, + { CAP_SYS_RAWIO, SCMP_SYS(ioperm)}, + { CAP_SYS_BOOT, SCMP_SYS(kexec_load)}, + { CAP_SYS_ADMIN, SCMP_SYS(swapon)}, + { CAP_SYS_ADMIN, SCMP_SYS(swapoff)}, + { CAP_SYS_ADMIN, SCMP_SYS(open_by_handle_at)}, + { CAP_SYS_MODULE, SCMP_SYS(init_module)}, + { CAP_SYS_MODULE, SCMP_SYS(finit_module)}, + { CAP_SYS_MODULE, SCMP_SYS(delete_module)}, }; scmp_filter_ctx seccomp; @@ -2597,7 +2597,10 @@ static int setup_seccomp(void) { } for (i = 0; i < ELEMENTSOF(blacklist); i++) { - r = seccomp_rule_add(seccomp, SCMP_ACT_ERRNO(EPERM), blacklist[i], 0); + if (arg_retain & (1ULL << blacklist[i].capability)) + continue; + + r = seccomp_rule_add(seccomp, SCMP_ACT_ERRNO(EPERM), blacklist[i].syscall_num, 0); if (r == -EFAULT) continue; /* unknown syscall */ if (r < 0) { @@ -2606,19 +2609,6 @@ static int setup_seccomp(void) { } } - /* If the CAP_SYS_MODULE capability is not requested then - * we'll block the kmod syscalls too */ - if (!(arg_retain & (1ULL << CAP_SYS_MODULE))) { - for (i = 0; i < ELEMENTSOF(kmod_blacklist); i++) { - r = seccomp_rule_add(seccomp, SCMP_ACT_ERRNO(EPERM), kmod_blacklist[i], 0); - if (r == -EFAULT) - continue; /* unknown syscall */ - if (r < 0) { - log_error_errno(r, "Failed to block syscall: %m"); - goto finish; - } - } - } /* Audit is broken in containers, much of the userspace audit -- 2.30.2