From f07ebb8888ea42f744890a727e8f6799a1086915 Mon Sep 17 00:00:00 2001 From: pjd Date: Sat, 2 Mar 2013 00:53:12 +0000 Subject: Merge Capsicum overhaul: - Capability is no longer separate descriptor type. Now every descriptor has set of its own capability rights. - The cap_new(2) system call is left, but it is no longer documented and should not be used in new code. - The new syscall cap_rights_limit(2) should be used instead of cap_new(2), which limits capability rights of the given descriptor without creating a new one. - The cap_getrights(2) syscall is renamed to cap_rights_get(2). - If CAP_IOCTL capability right is present we can further reduce allowed ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed ioctls can be retrived with cap_ioctls_get(2) syscall. - If CAP_FCNTL capability right is present we can further reduce fcntls that can be used with the new cap_fcntls_limit(2) syscall and retrive them with cap_fcntls_get(2). - To support ioctl and fcntl white-listing the filedesc structure was heavly modified. - The audit subsystem, kdump and procstat tools were updated to recognize new syscalls. - Capability rights were revised and eventhough I tried hard to provide backward API and ABI compatibility there are some incompatible changes that are described in detail below: CAP_CREATE old behaviour: - Allow for openat(2)+O_CREAT. - Allow for linkat(2). - Allow for symlinkat(2). CAP_CREATE new behaviour: - Allow for openat(2)+O_CREAT. Added CAP_LINKAT: - Allow for linkat(2). ABI: Reuses CAP_RMDIR bit. - Allow to be target for renameat(2). Added CAP_SYMLINKAT: - Allow for symlinkat(2). Removed CAP_DELETE. Old behaviour: - Allow for unlinkat(2) when removing non-directory object. - Allow to be source for renameat(2). Removed CAP_RMDIR. Old behaviour: - Allow for unlinkat(2) when removing directory. Added CAP_RENAMEAT: - Required for source directory for the renameat(2) syscall. Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR): - Allow for unlinkat(2) on any object. - Required if target of renameat(2) exists and will be removed by this call. Removed CAP_MAPEXEC. CAP_MMAP old behaviour: - Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and PROT_WRITE. CAP_MMAP new behaviour: - Allow for mmap(2)+PROT_NONE. Added CAP_MMAP_R: - Allow for mmap(PROT_READ). Added CAP_MMAP_W: - Allow for mmap(PROT_WRITE). Added CAP_MMAP_X: - Allow for mmap(PROT_EXEC). Added CAP_MMAP_RW: - Allow for mmap(PROT_READ | PROT_WRITE). Added CAP_MMAP_RX: - Allow for mmap(PROT_READ | PROT_EXEC). Added CAP_MMAP_WX: - Allow for mmap(PROT_WRITE | PROT_EXEC). Added CAP_MMAP_RWX: - Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC). Renamed CAP_MKDIR to CAP_MKDIRAT. Renamed CAP_MKFIFO to CAP_MKFIFOAT. Renamed CAP_MKNODE to CAP_MKNODEAT. CAP_READ old behaviour: - Allow pread(2). - Disallow read(2), readv(2) (if there is no CAP_SEEK). CAP_READ new behaviour: - Allow read(2), readv(2). - Disallow pread(2) (CAP_SEEK was also required). CAP_WRITE old behaviour: - Allow pwrite(2). - Disallow write(2), writev(2) (if there is no CAP_SEEK). CAP_WRITE new behaviour: - Allow write(2), writev(2). - Disallow pwrite(2) (CAP_SEEK was also required). Added convinient defines: #define CAP_PREAD (CAP_SEEK | CAP_READ) #define CAP_PWRITE (CAP_SEEK | CAP_WRITE) #define CAP_MMAP_R (CAP_MMAP | CAP_SEEK | CAP_READ) #define CAP_MMAP_W (CAP_MMAP | CAP_SEEK | CAP_WRITE) #define CAP_MMAP_X (CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL) #define CAP_MMAP_RW (CAP_MMAP_R | CAP_MMAP_W) #define CAP_MMAP_RX (CAP_MMAP_R | CAP_MMAP_X) #define CAP_MMAP_WX (CAP_MMAP_W | CAP_MMAP_X) #define CAP_MMAP_RWX (CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X) #define CAP_RECV CAP_READ #define CAP_SEND CAP_WRITE #define CAP_SOCK_CLIENT \ (CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \ CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN) #define CAP_SOCK_SERVER \ (CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \ CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \ CAP_SETSOCKOPT | CAP_SHUTDOWN) Added defines for backward API compatibility: #define CAP_MAPEXEC CAP_MMAP_X #define CAP_DELETE CAP_UNLINKAT #define CAP_MKDIR CAP_MKDIRAT #define CAP_RMDIR CAP_UNLINKAT #define CAP_MKFIFO CAP_MKFIFOAT #define CAP_MKNOD CAP_MKNODAT #define CAP_SOCK_ALL (CAP_SOCK_CLIENT | CAP_SOCK_SERVER) Sponsored by: The FreeBSD Foundation Reviewed by: Christoph Mallon Many aspects discussed with: rwatson, benl, jonathan ABI compatibility discussed with: kib --- sys/sys/capability.h | 197 +++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 152 insertions(+), 45 deletions(-) (limited to 'sys/sys/capability.h') diff --git a/sys/sys/capability.h b/sys/sys/capability.h index a163c4c..27e56c2 100644 --- a/sys/sys/capability.h +++ b/sys/sys/capability.h @@ -1,10 +1,14 @@ /*- * Copyright (c) 2008-2010 Robert N. M. Watson + * Copyright (c) 2012 FreeBSD Foundation * All rights reserved. * * This software was developed at the University of Cambridge Computer * Laboratory with support from a grant from Google, Inc. * + * Portions of this software were developed by Pawel Jakub Dawidek under + * sponsorship from the FreeBSD Foundation. + * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: @@ -36,9 +40,10 @@ #define _SYS_CAPABILITY_H_ #include -#include +#include #include +#include /* * Possible rights on capabilities. @@ -54,34 +59,69 @@ * involve reads or writes depending a great deal on context. */ -/* General file I/O. */ -#define CAP_READ 0x0000000000000001ULL /* read/recv */ -#define CAP_WRITE 0x0000000000000002ULL /* write/send */ -#define CAP_MMAP 0x0000000000000004ULL /* mmap */ -#define CAP_MAPEXEC 0x0000000000000008ULL /* mmap(2) as exec */ +#define CAP_NONE 0x0000000000000000ULL + +/* + * General file I/O. + */ +/* Allows for openat(O_RDONLY), read(2), readv(2). */ +#define CAP_READ 0x0000000000000001ULL +/* Allows for openat(O_WRONLY | O_APPEND), write(2), writev(2). */ +#define CAP_WRITE 0x0000000000000002ULL +/* Allows for lseek(2). */ +#define CAP_SEEK 0x0000000000000080ULL +/* Allows for pread(2), preadv(2). */ +#define CAP_PREAD (CAP_SEEK | CAP_READ) +/* Allows for openat(O_WRONLY) (without O_APPEND), pwrite(2), pwritev(2). */ +#define CAP_PWRITE (CAP_SEEK | CAP_WRITE) +/* Allows for mmap(PROT_NONE). */ +#define CAP_MMAP 0x0000000000000004ULL +/* Allows for mmap(PROT_READ). */ +#define CAP_MMAP_R (CAP_MMAP | CAP_SEEK | CAP_READ) +/* Allows for mmap(PROT_WRITE). */ +#define CAP_MMAP_W (CAP_MMAP | CAP_SEEK | CAP_WRITE) +/* Allows for mmap(PROT_EXEC). */ +#define CAP_MMAP_X (CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL) +/* Allows for mmap(PROT_READ | PROT_WRITE). */ +#define CAP_MMAP_RW (CAP_MMAP_R | CAP_MMAP_W) +/* Allows for mmap(PROT_READ | PROT_EXEC). */ +#define CAP_MMAP_RX (CAP_MMAP_R | CAP_MMAP_X) +/* Allows for mmap(PROT_WRITE | PROT_EXEC). */ +#define CAP_MMAP_WX (CAP_MMAP_W | CAP_MMAP_X) +/* Allows for mmap(PROT_READ | PROT_WRITE | PROT_EXEC). */ +#define CAP_MMAP_RWX (CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X) +/* Allows for openat(O_CREAT). */ +#define CAP_CREATE 0x0000000000080000ULL +/* Allows for openat(O_EXEC) and fexecve(2) in turn. */ #define CAP_FEXECVE 0x0000000000000010ULL +/* Allows for openat(O_SYNC), openat(O_FSYNC), fsync(2). */ #define CAP_FSYNC 0x0000000000000020ULL +/* Allows for openat(O_TRUNC), ftruncate(2). */ #define CAP_FTRUNCATE 0x0000000000000040ULL -#define CAP_SEEK 0x0000000000000080ULL /* VFS methods. */ -#define CAP_FCHFLAGS 0x0000000000000100ULL #define CAP_FCHDIR 0x0000000000000200ULL +#define CAP_FCHFLAGS 0x0000000000000100ULL #define CAP_FCHMOD 0x0000000000000400ULL +#define CAP_FCHMODAT CAP_FCHMOD #define CAP_FCHOWN 0x0000000000000800ULL +#define CAP_FCHOWNAT CAP_FCHOWN #define CAP_FCNTL 0x0000000000001000ULL -#define CAP_FPATHCONF 0x0000000000002000ULL #define CAP_FLOCK 0x0000000000004000ULL +#define CAP_FPATHCONF 0x0000000000002000ULL #define CAP_FSCK 0x0000000000008000ULL #define CAP_FSTAT 0x0000000000010000ULL +#define CAP_FSTATAT CAP_FSTAT #define CAP_FSTATFS 0x0000000000020000ULL #define CAP_FUTIMES 0x0000000000040000ULL -#define CAP_CREATE 0x0000000000080000ULL -#define CAP_DELETE 0x0000000000100000ULL -#define CAP_MKDIR 0x0000000000200000ULL -#define CAP_RMDIR 0x0000000000400000ULL -#define CAP_MKFIFO 0x0000000000800000ULL -#define CAP_MKNOD 0x0080000000000000ULL +#define CAP_FUTIMESAT CAP_FUTIMES +#define CAP_LINKAT 0x0000000000400000ULL +#define CAP_MKDIRAT 0x0000000000200000ULL +#define CAP_MKFIFOAT 0x0000000000800000ULL +#define CAP_MKNODAT 0x0080000000000000ULL +#define CAP_RENAMEAT 0x0200000000000000ULL +#define CAP_SYMLINKAT 0x0100000000000000ULL +#define CAP_UNLINKAT 0x0000000000100000ULL /* Lookups - used to constrain *at() calls. */ #define CAP_LOOKUP 0x0000000001000000ULL @@ -107,13 +147,18 @@ #define CAP_GETSOCKOPT 0x0000004000000000ULL #define CAP_LISTEN 0x0000008000000000ULL #define CAP_PEELOFF 0x0000010000000000ULL +#define CAP_RECV CAP_READ +#define CAP_SEND CAP_WRITE #define CAP_SETSOCKOPT 0x0000020000000000ULL #define CAP_SHUTDOWN 0x0000040000000000ULL -#define CAP_SOCK_ALL \ - (CAP_ACCEPT | CAP_BIND | CAP_CONNECT \ - | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT \ - | CAP_LISTEN | CAP_PEELOFF | CAP_SETSOCKOPT | CAP_SHUTDOWN) +#define CAP_SOCK_CLIENT \ + (CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \ + CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN) +#define CAP_SOCK_SERVER \ + (CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \ + CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \ + CAP_SETSOCKOPT | CAP_SHUTDOWN) /* Mandatory Access Control. */ #define CAP_MAC_GET 0x0000080000000000ULL @@ -138,40 +183,77 @@ #define CAP_PDKILL 0x0040000000000000ULL /* The mask of all valid method rights. */ -#define CAP_MASK_VALID 0x00ffffffffffffffULL +#define CAP_MASK_VALID 0x03ffffffffffffffULL +#define CAP_ALL CAP_MASK_VALID -#ifdef _KERNEL +/* Available bits. */ +#define CAP_UNUSED5 0x0400000000000000ULL +#define CAP_UNUSED4 0x0800000000000000ULL +#define CAP_UNUSED3 0x1000000000000000ULL +#define CAP_UNUSED2 0x2000000000000000ULL +#define CAP_UNUSED1 0x4000000000000000ULL +#define CAP_UNUSED0 0x8000000000000000ULL -#define IN_CAPABILITY_MODE(td) (td->td_ucred->cr_flags & CRED_FLAG_CAPMODE) +/* + * The following defines are provided for backward API compatibility and + * should not be used in new code. + */ +#define CAP_MAPEXEC CAP_MMAP_X +#define CAP_DELETE CAP_UNLINKAT +#define CAP_MKDIR CAP_MKDIRAT +#define CAP_RMDIR CAP_UNLINKAT +#define CAP_MKFIFO CAP_MKFIFOAT +#define CAP_MKNOD CAP_MKNODAT +#define CAP_SOCK_ALL (CAP_SOCK_CLIENT | CAP_SOCK_SERVER) /* - * Create a capability to wrap a file object. + * Allowed fcntl(2) commands. */ -int kern_capwrap(struct thread *td, struct file *fp, cap_rights_t rights, - int *capfd); +#define CAP_FCNTL_GETFL (1 << F_GETFL) +#define CAP_FCNTL_SETFL (1 << F_SETFL) +#if __BSD_VISIBLE || __XSI_VISIBLE || __POSIX_VISIBLE >= 200112 +#define CAP_FCNTL_GETOWN (1 << F_GETOWN) +#define CAP_FCNTL_SETOWN (1 << F_SETOWN) +#endif +#if __BSD_VISIBLE || __XSI_VISIBLE || __POSIX_VISIBLE >= 200112 +#define CAP_FCNTL_ALL (CAP_FCNTL_GETFL | CAP_FCNTL_SETFL | \ + CAP_FCNTL_GETOWN | CAP_FCNTL_SETOWN) +#else +#define CAP_FCNTL_ALL (CAP_FCNTL_GETFL | CAP_FCNTL_SETFL) +#endif + +#define CAP_IOCTLS_ALL SSIZE_MAX + +#ifdef _KERNEL + +#include + +#define IN_CAPABILITY_MODE(td) ((td->td_ucred->cr_flags & CRED_FLAG_CAPMODE) != 0) + +struct filedesc; /* - * Unwrap a capability if its rights mask is a superset of 'rights'. - * - * Unwrapping a non-capability is effectively a no-op; the value of fp_cap - * is simply copied into fpp. + * Test whether a capability grants the requested rights. + */ +int cap_check(cap_rights_t have, cap_rights_t need); +/* + * Convert capability rights into VM access flags. */ -int cap_funwrap(struct file *fp_cap, cap_rights_t rights, - struct file **fpp); -int cap_funwrap_mmap(struct file *fp_cap, cap_rights_t rights, - u_char *maxprotp, struct file **fpp); +u_char cap_rights_to_vmprot(cap_rights_t have); /* * For the purposes of procstat(1) and similar tools, allow kern_descrip.c to - * extract the rights from a capability. However, this should not be used by - * kernel code generally, instead cap_funwrap() should be used in order to - * keep all access control in one place. + * extract the rights from a capability. */ -cap_rights_t cap_rights(struct file *fp_cap); +cap_rights_t cap_rights(struct filedesc *fdp, int fd); + +int cap_ioctl_check(struct filedesc *fdp, int fd, u_long cmd); +int cap_fcntl_check(struct filedesc *fdp, int fd, int cmd); #else /* !_KERNEL */ __BEGIN_DECLS +#include /* * cap_enter(): Cause the process to enter capability mode, which will @@ -187,21 +269,46 @@ __BEGIN_DECLS int cap_enter(void); /* - * cap_getmode(): Are we in capability mode? + * Are we sandboxed (in capability mode)? + * This is a libc wrapper around the cap_getmode(2) system call. */ -int cap_getmode(u_int* modep); +bool cap_sandboxed(void); /* - * cap_new(): Create a new capability derived from an existing file - * descriptor with the specified rights. If the existing file descriptor is - * a capability, then the new rights must be a subset of the existing rights. + * cap_getmode(): Are we in capability mode? */ -int cap_new(int fd, cap_rights_t rights); +int cap_getmode(u_int *modep); /* - * cap_getrights(): Query the rights on a capability. + * Limits capability rights for the given descriptor (CAP_*). + */ +int cap_rights_limit(int fd, cap_rights_t rights); +/* + * Returns bitmask of capability rights for the given descriptor. */ -int cap_getrights(int fd, cap_rights_t *rightsp); +int cap_rights_get(int fd, cap_rights_t *rightsp); +/* + * Limits allowed ioctls for the given descriptor. + */ +int cap_ioctls_limit(int fd, const unsigned long *cmds, size_t ncmds); +/* + * Returns array of allowed ioctls for the given descriptor. + * If all ioctls are allowed, the cmds array is not populated and + * the function returns CAP_IOCTLS_ALL. + */ +ssize_t cap_ioctls_get(int fd, unsigned long *cmds, size_t maxcmds); +/* + * Limits allowed fcntls for the given descriptor (CAP_FCNTL_*). + */ +int cap_fcntls_limit(int fd, uint32_t fcntlrights); +/* + * Returns bitmask of allowed fcntls for the given descriptor. + */ +int cap_fcntls_get(int fd, uint32_t *fcntlrightsp); + +/* For backward compatibility. */ +int cap_new(int fd, cap_rights_t rights); +#define cap_getrights(fd, rightsp) cap_rights_get((fd), (rightsp)) __END_DECLS -- cgit v1.1