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d049f74f2d
The get_dumpable() return value is not boolean. Most users of the
function actually want to be testing for non-SUID_DUMP_USER(1) rather than
SUID_DUMP_DISABLE(0). The SUID_DUMP_ROOT(2) is also considered a
protected state. Almost all places did this correctly, excepting the two
places fixed in this patch.
Wrong logic:
if (dumpable == SUID_DUMP_DISABLE) { /* be protective */ }
or
if (dumpable == 0) { /* be protective */ }
or
if (!dumpable) { /* be protective */ }
Correct logic:
if (dumpable != SUID_DUMP_USER) { /* be protective */ }
or
if (dumpable != 1) { /* be protective */ }
Without this patch, if the system had set the sysctl fs/suid_dumpable=2, a
user was able to ptrace attach to processes that had dropped privileges to
that user. (This may have been partially mitigated if Yama was enabled.)
The macros have been moved into the file that declares get/set_dumpable(),
which means things like the ia64 code can see them too.
CVE-2013-2929
Reported-by: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
121 lines
3.8 KiB
C
121 lines
3.8 KiB
C
#ifndef _LINUX_BINFMTS_H
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#define _LINUX_BINFMTS_H
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#include <linux/sched.h>
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#include <linux/unistd.h>
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#include <asm/exec.h>
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#include <uapi/linux/binfmts.h>
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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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unsigned long vma_pages;
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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
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cred_prepared:1,/* true if creds already prepared (multiple
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* preps happen for interpreters) */
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cap_effective:1;/* true if has elevated effective capabilities,
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* false if not; except for init which inherits
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* its parent's caps anyway */
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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; /* only for search_binary_handler() */
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struct file * file;
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struct cred *cred; /* new credentials */
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int unsafe; /* how unsafe this exec is (mask of LSM_UNSAFE_*) */
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unsigned int per_clear; /* bits to clear in current->personality */
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int argc, envc;
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const char * filename; /* Name of binary as seen by procps */
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const 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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char tcomm[TASK_COMM_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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/* Function parameter for binfmt->coredump */
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struct coredump_params {
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siginfo_t *siginfo;
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struct pt_regs *regs;
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struct file *file;
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unsigned long limit;
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unsigned long mm_flags;
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};
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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 *);
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int (*load_shlib)(struct file *);
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int (*core_dump)(struct coredump_params *cprm);
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unsigned long min_coredump; /* minimal dump size */
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};
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extern void __register_binfmt(struct linux_binfmt *fmt, int insert);
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/* Registration of default binfmt handlers */
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static inline void register_binfmt(struct linux_binfmt *fmt)
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{
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__register_binfmt(fmt, 0);
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}
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/* Same as above, but adds a new binfmt at the top of the list */
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static inline void insert_binfmt(struct linux_binfmt *fmt)
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{
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__register_binfmt(fmt, 1);
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}
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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 *);
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extern int flush_old_exec(struct linux_binprm * bprm);
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extern void setup_new_exec(struct linux_binprm * bprm);
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extern void would_dump(struct linux_binprm *, struct file *);
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extern int suid_dumpable;
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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_change_interp(char *interp, struct linux_binprm *bprm);
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extern int copy_strings_kernel(int argc, const char *const *argv,
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struct linux_binprm *bprm);
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extern int prepare_bprm_creds(struct linux_binprm *bprm);
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extern void install_exec_creds(struct linux_binprm *bprm);
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extern void set_binfmt(struct linux_binfmt *new);
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extern void free_bprm(struct linux_binprm *);
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extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
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#endif /* _LINUX_BINFMTS_H */
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