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FILE5_42
src/seccomp.c
287 строк
7 KB
Christos Zoulas
fix clang warnings (Avinash Sonawane)
24 сен 2021, 17:17
24 сен 2021, 17:17
ac3fb1f
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/* * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice immediately at the beginning of the file, without modification, * this list of conditions, and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * libseccomp hooks. */ #include "file.h" #ifndef lint FILE_RCSID("@(#)$File: seccomp.c,v 1.21 2021/09/24 14:17:24 christos Exp $") #endif /* lint */ #if HAVE_LIBSECCOMP #include <seccomp.h> /* libseccomp */ #include <sys/prctl.h> /* prctl */ #include <sys/ioctl.h> #include <sys/socket.h> #include <termios.h> #include <fcntl.h> #include <stdlib.h> #include <errno.h> #define DENY_RULE(call) \ do \ if (seccomp_rule_add (ctx, SCMP_ACT_KILL, SCMP_SYS(call), 0) == -1) \ goto out; \ while (/*CONSTCOND*/0) #define ALLOW_RULE(call) \ do \ if (seccomp_rule_add (ctx, SCMP_ACT_ALLOW, SCMP_SYS(call), 0) == -1) \ goto out; \ while (/*CONSTCOND*/0) #define ALLOW_IOCTL_RULE(param) \ do \ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(ioctl), 1, \ SCMP_CMP(1, SCMP_CMP_EQ, (scmp_datum_t)param, \ (scmp_datum_t)0)) == -1) \ goto out; \ while (/*CONSTCOND*/0) static scmp_filter_ctx ctx; int enable_sandbox_basic(void) { if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1) return -1; if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) == -1) return -1; // initialize the filter ctx = seccomp_init(SCMP_ACT_ALLOW); if (ctx == NULL) return 1; DENY_RULE(_sysctl); DENY_RULE(acct); DENY_RULE(add_key); DENY_RULE(adjtimex); DENY_RULE(chroot); DENY_RULE(clock_adjtime); DENY_RULE(create_module); DENY_RULE(delete_module); DENY_RULE(fanotify_init); DENY_RULE(finit_module); DENY_RULE(get_kernel_syms); DENY_RULE(get_mempolicy); DENY_RULE(init_module); DENY_RULE(io_cancel); DENY_RULE(io_destroy); DENY_RULE(io_getevents); DENY_RULE(io_setup); DENY_RULE(io_submit); DENY_RULE(ioperm); DENY_RULE(iopl); DENY_RULE(ioprio_set); DENY_RULE(kcmp); #ifdef __NR_kexec_file_load DENY_RULE(kexec_file_load); #endif DENY_RULE(kexec_load); DENY_RULE(keyctl); DENY_RULE(lookup_dcookie); DENY_RULE(mbind); DENY_RULE(nfsservctl); DENY_RULE(migrate_pages); DENY_RULE(modify_ldt); DENY_RULE(mount); DENY_RULE(move_pages); DENY_RULE(name_to_handle_at); DENY_RULE(open_by_handle_at); DENY_RULE(perf_event_open); DENY_RULE(pivot_root); DENY_RULE(process_vm_readv); DENY_RULE(process_vm_writev); DENY_RULE(ptrace); DENY_RULE(reboot); DENY_RULE(remap_file_pages); DENY_RULE(request_key); DENY_RULE(set_mempolicy); DENY_RULE(swapoff); DENY_RULE(swapon); DENY_RULE(sysfs); DENY_RULE(syslog); DENY_RULE(tuxcall); DENY_RULE(umount2); DENY_RULE(uselib); DENY_RULE(vmsplice); // blocking dangerous syscalls that file should not need DENY_RULE (execve); DENY_RULE (socket); // ... // applying filter... if (seccomp_load (ctx) == -1) goto out; // free ctx after the filter has been loaded into the kernel seccomp_release(ctx); return 0; out: seccomp_release(ctx); return -1; } int enable_sandbox_full(void) { // prevent child processes from getting more priv e.g. via setuid, // capabilities, ... if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1) return -1; if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) == -1) return -1; // initialize the filter ctx = seccomp_init(SCMP_ACT_KILL); if (ctx == NULL) return -1; ALLOW_RULE(access); ALLOW_RULE(brk); ALLOW_RULE(close); ALLOW_RULE(dup2); ALLOW_RULE(exit); ALLOW_RULE(exit_group); #ifdef __NR_faccessat ALLOW_RULE(faccessat); #endif ALLOW_RULE(fcntl); ALLOW_RULE(fcntl64); ALLOW_RULE(fstat); ALLOW_RULE(fstat64); #ifdef __NR_fstatat64 ALLOW_RULE(fstatat64); #endif ALLOW_RULE(futex); ALLOW_RULE(getdents); #ifdef __NR_getdents64 ALLOW_RULE(getdents64); #endif #ifdef FIONREAD // called in src/compress.c under sread ALLOW_IOCTL_RULE(FIONREAD); #endif #ifdef TIOCGWINSZ // musl libc may call ioctl TIOCGWINSZ on stdout ALLOW_IOCTL_RULE(TIOCGWINSZ); #endif #ifdef TCGETS // glibc may call ioctl TCGETS on stdout on physical terminal ALLOW_IOCTL_RULE(TCGETS); #endif ALLOW_RULE(lseek); ALLOW_RULE(_llseek); ALLOW_RULE(lstat); ALLOW_RULE(lstat64); ALLOW_RULE(madvise); ALLOW_RULE(mmap); ALLOW_RULE(mmap2); ALLOW_RULE(mprotect); ALLOW_RULE(mremap); ALLOW_RULE(munmap); #ifdef __NR_newfstatat ALLOW_RULE(newfstatat); #endif ALLOW_RULE(open); ALLOW_RULE(openat); ALLOW_RULE(pread64); ALLOW_RULE(read); ALLOW_RULE(readlink); #ifdef __NR_readlinkat ALLOW_RULE(readlinkat); #endif ALLOW_RULE(rt_sigaction); ALLOW_RULE(rt_sigprocmask); ALLOW_RULE(rt_sigreturn); ALLOW_RULE(select); ALLOW_RULE(stat); ALLOW_RULE(statx); ALLOW_RULE(stat64); ALLOW_RULE(sysinfo); ALLOW_RULE(umask); // Used in file_pipe2file() ALLOW_RULE(getpid); // Used by glibc in file_pipe2file() ALLOW_RULE(unlink); ALLOW_RULE(write); ALLOW_RULE(writev); #if 0 // needed by valgrind ALLOW_RULE(gettid); ALLOW_RULE(rt_sigtimedwait); #endif #if 0 /* special restrictions for socket, only allow AF_UNIX/AF_LOCAL */ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 1, SCMP_CMP(0, SCMP_CMP_EQ, AF_UNIX)) == -1) goto out; if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(socket), 1, SCMP_CMP(0, SCMP_CMP_EQ, AF_LOCAL)) == -1) goto out; /* special restrictions for open, prevent opening files for writing */ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open), 1, SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY | O_RDWR, 0)) == -1) goto out; if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open), 1, SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_WRONLY, O_WRONLY)) == -1) goto out; if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open), 1, SCMP_CMP(1, SCMP_CMP_MASKED_EQ, O_RDWR, O_RDWR)) == -1) goto out; /* allow stderr */ if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(write), 1, SCMP_CMP(0, SCMP_CMP_EQ, 2)) == -1) goto out; #endif // applying filter... if (seccomp_load(ctx) == -1) goto out; // free ctx after the filter has been loaded into the kernel seccomp_release(ctx); return 0; out: // something went wrong seccomp_release(ctx); return -1; } #endif