bf2a9a3963
binfmt_script and binfmt_misc disallow recursion to avoid stack overflow using sh_bang and misc_bang. It causes problem in some cases: $ echo '#!/bin/ls' > /tmp/t0 $ echo '#!/tmp/t0' > /tmp/t1 $ echo '#!/tmp/t1' > /tmp/t2 $ chmod +x /tmp/t* $ /tmp/t2 zsh: exec format error: /tmp/t2 Similar problem with binfmt_misc. This patch introduces field 'recursion_depth' into struct linux_binprm to track recursion level in binfmt_misc and binfmt_script. If recursion level more then BINPRM_MAX_RECURSION it generates -ENOEXEC. [akpm@linux-foundation.org: make linux_binprm.recursion_depth a uint] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
110 lines
3.4 KiB
C
110 lines
3.4 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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unsigned int sh_bang:1,
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misc_bang:1;
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#ifdef __alpha__
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unsigned int taso:1;
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#endif
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unsigned int recursion_depth;
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struct file * file;
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int e_uid, e_gid;
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kernel_cap_t cap_post_exec_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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};
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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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#define BINPRM_MAX_RECURSION 4
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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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extern void free_bprm(struct linux_binprm *);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_BINFMTS_H */
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