b53767719b
Implement file posix capabilities. This allows programs to be given a subset of root's powers regardless of who runs them, without having to use setuid and giving the binary all of root's powers. This version works with Kaigai Kohei's userspace tools, found at http://www.kaigai.gr.jp/index.php. For more information on how to use this patch, Chris Friedhoff has posted a nice page at http://www.friedhoff.org/fscaps.html. Changelog: Nov 27: Incorporate fixes from Andrew Morton (security-introduce-file-caps-tweaks and security-introduce-file-caps-warning-fix) Fix Kconfig dependency. Fix change signaling behavior when file caps are not compiled in. Nov 13: Integrate comments from Alexey: Remove CONFIG_ ifdef from capability.h, and use %zd for printing a size_t. Nov 13: Fix endianness warnings by sparse as suggested by Alexey Dobriyan. Nov 09: Address warnings of unused variables at cap_bprm_set_security when file capabilities are disabled, and simultaneously clean up the code a little, by pulling the new code into a helper function. Nov 08: For pointers to required userspace tools and how to use them, see http://www.friedhoff.org/fscaps.html. Nov 07: Fix the calculation of the highest bit checked in check_cap_sanity(). Nov 07: Allow file caps to be enabled without CONFIG_SECURITY, since capabilities are the default. Hook cap_task_setscheduler when !CONFIG_SECURITY. Move capable(TASK_KILL) to end of cap_task_kill to reduce audit messages. Nov 05: Add secondary calls in selinux/hooks.c to task_setioprio and task_setscheduler so that selinux and capabilities with file cap support can be stacked. Sep 05: As Seth Arnold points out, uid checks are out of place for capability code. Sep 01: Define task_setscheduler, task_setioprio, cap_task_kill, and task_setnice to make sure a user cannot affect a process in which they called a program with some fscaps. One remaining question is the note under task_setscheduler: are we ok with CAP_SYS_NICE being sufficient to confine a process to a cpuset? It is a semantic change, as without fsccaps, attach_task doesn't allow CAP_SYS_NICE to override the uid equivalence check. But since it uses security_task_setscheduler, which elsewhere is used where CAP_SYS_NICE can be used to override the uid equivalence check, fixing it might be tough. task_setscheduler note: this also controls cpuset:attach_task. Are we ok with CAP_SYS_NICE being used to confine to a cpuset? task_setioprio task_setnice sys_setpriority uses this (through set_one_prio) for another process. Need same checks as setrlimit Aug 21: Updated secureexec implementation to reflect the fact that euid and uid might be the same and nonzero, but the process might still have elevated caps. Aug 15: Handle endianness of xattrs. Enforce capability version match between kernel and disk. Enforce that no bits beyond the known max capability are set, else return -EPERM. With this extra processing, it may be worth reconsidering doing all the work at bprm_set_security rather than d_instantiate. Aug 10: Always call getxattr at bprm_set_security, rather than caching it at d_instantiate. [morgan@kernel.org: file-caps clean up for linux/capability.h] [bunk@kernel.org: unexport cap_inode_killpriv] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
104 lines
3.3 KiB
C
104 lines
3.3 KiB
C
#ifndef _LINUX_BINFMTS_H
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#define _LINUX_BINFMTS_H
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#include <linux/capability.h>
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struct pt_regs;
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/*
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* These are the maximum length and maximum number of strings passed to the
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* execve() system call. MAX_ARG_STRLEN is essentially random but serves to
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* prevent the kernel from being unduly impacted by misaddressed pointers.
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* MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
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*/
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#define MAX_ARG_STRLEN (PAGE_SIZE * 32)
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#define MAX_ARG_STRINGS 0x7FFFFFFF
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/* sizeof(linux_binprm->buf) */
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#define BINPRM_BUF_SIZE 128
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#ifdef __KERNEL__
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#define CORENAME_MAX_SIZE 128
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/*
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* This structure is used to hold the arguments that are used when loading binaries.
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*/
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struct linux_binprm{
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char buf[BINPRM_BUF_SIZE];
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#ifdef CONFIG_MMU
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struct vm_area_struct *vma;
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#else
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# define MAX_ARG_PAGES 32
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struct page *page[MAX_ARG_PAGES];
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#endif
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struct mm_struct *mm;
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unsigned long p; /* current top of mem */
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int sh_bang;
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struct file * file;
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int e_uid, e_gid;
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kernel_cap_t cap_inheritable, cap_permitted;
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bool cap_effective;
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void *security;
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int argc, envc;
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char * filename; /* Name of binary as seen by procps */
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char * interp; /* Name of the binary really executed. Most
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of the time same as filename, but could be
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different for binfmt_{misc,script} */
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unsigned interp_flags;
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unsigned interp_data;
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unsigned long loader, exec;
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unsigned long argv_len;
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};
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#define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
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#define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)
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/* fd of the binary should be passed to the interpreter */
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#define BINPRM_FLAGS_EXECFD_BIT 1
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#define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT)
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/*
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* This structure defines the functions that are used to load the binary formats that
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* linux accepts.
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*/
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struct linux_binfmt {
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struct list_head lh;
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struct module *module;
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int (*load_binary)(struct linux_binprm *, struct pt_regs * regs);
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int (*load_shlib)(struct file *);
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int (*core_dump)(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
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unsigned long min_coredump; /* minimal dump size */
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int hasvdso;
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};
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extern int register_binfmt(struct linux_binfmt *);
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extern void unregister_binfmt(struct linux_binfmt *);
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extern int prepare_binprm(struct linux_binprm *);
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extern int __must_check remove_arg_zero(struct linux_binprm *);
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extern int search_binary_handler(struct linux_binprm *,struct pt_regs *);
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extern int flush_old_exec(struct linux_binprm * bprm);
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extern int suid_dumpable;
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#define SUID_DUMP_DISABLE 0 /* No setuid dumping */
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#define SUID_DUMP_USER 1 /* Dump as user of process */
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#define SUID_DUMP_ROOT 2 /* Dump as root */
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/* Stack area protections */
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#define EXSTACK_DEFAULT 0 /* Whatever the arch defaults to */
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#define EXSTACK_DISABLE_X 1 /* Disable executable stacks */
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#define EXSTACK_ENABLE_X 2 /* Enable executable stacks */
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extern int setup_arg_pages(struct linux_binprm * bprm,
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unsigned long stack_top,
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int executable_stack);
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extern int bprm_mm_init(struct linux_binprm *bprm);
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extern int copy_strings_kernel(int argc,char ** argv,struct linux_binprm *bprm);
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extern void compute_creds(struct linux_binprm *binprm);
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extern int do_coredump(long signr, int exit_code, struct pt_regs * regs);
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extern int set_binfmt(struct linux_binfmt *new);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_BINFMTS_H */
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