mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-03 06:56:43 +07:00
643ad15d47
Pull x86 protection key support from Ingo Molnar: "This tree adds support for a new memory protection hardware feature that is available in upcoming Intel CPUs: 'protection keys' (pkeys). There's a background article at LWN.net: https://lwn.net/Articles/643797/ The gist is that protection keys allow the encoding of user-controllable permission masks in the pte. So instead of having a fixed protection mask in the pte (which needs a system call to change and works on a per page basis), the user can map a (handful of) protection mask variants and can change the masks runtime relatively cheaply, without having to change every single page in the affected virtual memory range. This allows the dynamic switching of the protection bits of large amounts of virtual memory, via user-space instructions. It also allows more precise control of MMU permission bits: for example the executable bit is separate from the read bit (see more about that below). This tree adds the MM infrastructure and low level x86 glue needed for that, plus it adds a high level API to make use of protection keys - if a user-space application calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice this special case, and will set a special protection key on this memory range. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. So using protection keys the kernel is able to implement 'true' PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies PROT_READ as well. Unreadable executable mappings have security advantages: they cannot be read via information leaks to figure out ASLR details, nor can they be scanned for ROP gadgets - and they cannot be used by exploits for data purposes either. We know about no user-space code that relies on pure PROT_EXEC mappings today, but binary loaders could start making use of this new feature to map binaries and libraries in a more secure fashion. There is other pending pkeys work that offers more high level system call APIs to manage protection keys - but those are not part of this pull request. Right now there's a Kconfig that controls this feature (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled (like most x86 CPU feature enablement code that has no runtime overhead), but it's not user-configurable at the moment. If there's any serious problem with this then we can make it configurable and/or flip the default" * 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) x86/mm/pkeys: Fix mismerge of protection keys CPUID bits mm/pkeys: Fix siginfo ABI breakage caused by new u64 field x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA mm/core, x86/mm/pkeys: Add execute-only protection keys support x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags x86/mm/pkeys: Allow kernel to modify user pkey rights register x86/fpu: Allow setting of XSAVE state x86/mm: Factor out LDT init from context init mm/core, x86/mm/pkeys: Add arch_validate_pkey() mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits() x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU x86/mm/pkeys: Add Kconfig prompt to existing config option x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps x86/mm/pkeys: Dump PKRU with other kernel registers mm/core, x86/mm/pkeys: Differentiate instruction fetches x86/mm/pkeys: Optimize fault handling in access_error() mm/core: Do not enforce PKEY permissions on remote mm access um, pkeys: Add UML arch_*_access_permitted() methods mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys x86/mm/gup: Simplify get_user_pages() PTE bit handling ...
1848 lines
42 KiB
C
1848 lines
42 KiB
C
/*
|
|
* linux/fs/exec.c
|
|
*
|
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* Copyright (C) 1991, 1992 Linus Torvalds
|
|
*/
|
|
|
|
/*
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* #!-checking implemented by tytso.
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|
*/
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/*
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|
* Demand-loading implemented 01.12.91 - no need to read anything but
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* the header into memory. The inode of the executable is put into
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* "current->executable", and page faults do the actual loading. Clean.
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*
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* Once more I can proudly say that linux stood up to being changed: it
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* was less than 2 hours work to get demand-loading completely implemented.
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*
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* Demand loading changed July 1993 by Eric Youngdale. Use mmap instead,
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* current->executable is only used by the procfs. This allows a dispatch
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* table to check for several different types of binary formats. We keep
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* trying until we recognize the file or we run out of supported binary
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* formats.
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*/
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/mm.h>
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#include <linux/vmacache.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/swap.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/perf_event.h>
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#include <linux/highmem.h>
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#include <linux/spinlock.h>
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#include <linux/key.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <linux/utsname.h>
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#include <linux/pid_namespace.h>
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#include <linux/module.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/tsacct_kern.h>
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#include <linux/cn_proc.h>
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#include <linux/audit.h>
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#include <linux/tracehook.h>
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#include <linux/kmod.h>
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#include <linux/fsnotify.h>
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#include <linux/fs_struct.h>
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#include <linux/pipe_fs_i.h>
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#include <linux/oom.h>
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#include <linux/compat.h>
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#include <linux/vmalloc.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/tlb.h>
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#include <trace/events/task.h>
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#include "internal.h"
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#include <trace/events/sched.h>
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int suid_dumpable = 0;
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static LIST_HEAD(formats);
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static DEFINE_RWLOCK(binfmt_lock);
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void __register_binfmt(struct linux_binfmt * fmt, int insert)
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{
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BUG_ON(!fmt);
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if (WARN_ON(!fmt->load_binary))
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return;
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write_lock(&binfmt_lock);
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insert ? list_add(&fmt->lh, &formats) :
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list_add_tail(&fmt->lh, &formats);
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write_unlock(&binfmt_lock);
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}
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EXPORT_SYMBOL(__register_binfmt);
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void unregister_binfmt(struct linux_binfmt * fmt)
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|
{
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|
write_lock(&binfmt_lock);
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list_del(&fmt->lh);
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write_unlock(&binfmt_lock);
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}
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EXPORT_SYMBOL(unregister_binfmt);
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|
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static inline void put_binfmt(struct linux_binfmt * fmt)
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{
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module_put(fmt->module);
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}
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|
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|
bool path_noexec(const struct path *path)
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|
{
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|
return (path->mnt->mnt_flags & MNT_NOEXEC) ||
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|
(path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
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|
}
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|
|
|
#ifdef CONFIG_USELIB
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/*
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* Note that a shared library must be both readable and executable due to
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* security reasons.
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*
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|
* Also note that we take the address to load from from the file itself.
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|
*/
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SYSCALL_DEFINE1(uselib, const char __user *, library)
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|
{
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|
struct linux_binfmt *fmt;
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|
struct file *file;
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|
struct filename *tmp = getname(library);
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|
int error = PTR_ERR(tmp);
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|
static const struct open_flags uselib_flags = {
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|
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
|
|
.acc_mode = MAY_READ | MAY_EXEC,
|
|
.intent = LOOKUP_OPEN,
|
|
.lookup_flags = LOOKUP_FOLLOW,
|
|
};
|
|
|
|
if (IS_ERR(tmp))
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|
goto out;
|
|
|
|
file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);
|
|
putname(tmp);
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|
error = PTR_ERR(file);
|
|
if (IS_ERR(file))
|
|
goto out;
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|
error = -EINVAL;
|
|
if (!S_ISREG(file_inode(file)->i_mode))
|
|
goto exit;
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|
|
|
error = -EACCES;
|
|
if (path_noexec(&file->f_path))
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goto exit;
|
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|
|
fsnotify_open(file);
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|
|
|
error = -ENOEXEC;
|
|
|
|
read_lock(&binfmt_lock);
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list_for_each_entry(fmt, &formats, lh) {
|
|
if (!fmt->load_shlib)
|
|
continue;
|
|
if (!try_module_get(fmt->module))
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|
continue;
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|
read_unlock(&binfmt_lock);
|
|
error = fmt->load_shlib(file);
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|
read_lock(&binfmt_lock);
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|
put_binfmt(fmt);
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|
if (error != -ENOEXEC)
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|
break;
|
|
}
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|
read_unlock(&binfmt_lock);
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|
exit:
|
|
fput(file);
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|
out:
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|
return error;
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|
}
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|
#endif /* #ifdef CONFIG_USELIB */
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|
|
|
#ifdef CONFIG_MMU
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|
/*
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|
* The nascent bprm->mm is not visible until exec_mmap() but it can
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|
* use a lot of memory, account these pages in current->mm temporary
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|
* for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
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|
* change the counter back via acct_arg_size(0).
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|
*/
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|
static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
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|
{
|
|
struct mm_struct *mm = current->mm;
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|
long diff = (long)(pages - bprm->vma_pages);
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|
|
|
if (!mm || !diff)
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|
return;
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|
|
bprm->vma_pages = pages;
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|
add_mm_counter(mm, MM_ANONPAGES, diff);
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|
}
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|
|
|
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
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|
int write)
|
|
{
|
|
struct page *page;
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|
int ret;
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|
|
|
#ifdef CONFIG_STACK_GROWSUP
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|
if (write) {
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|
ret = expand_downwards(bprm->vma, pos);
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|
if (ret < 0)
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|
return NULL;
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|
}
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|
#endif
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/*
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|
* We are doing an exec(). 'current' is the process
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|
* doing the exec and bprm->mm is the new process's mm.
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|
*/
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|
ret = get_user_pages_remote(current, bprm->mm, pos, 1, write,
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|
1, &page, NULL);
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|
if (ret <= 0)
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|
return NULL;
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|
|
|
if (write) {
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|
unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
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|
struct rlimit *rlim;
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|
|
|
acct_arg_size(bprm, size / PAGE_SIZE);
|
|
|
|
/*
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|
* We've historically supported up to 32 pages (ARG_MAX)
|
|
* of argument strings even with small stacks
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|
*/
|
|
if (size <= ARG_MAX)
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|
return page;
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|
|
|
/*
|
|
* Limit to 1/4-th the stack size for the argv+env strings.
|
|
* This ensures that:
|
|
* - the remaining binfmt code will not run out of stack space,
|
|
* - the program will have a reasonable amount of stack left
|
|
* to work from.
|
|
*/
|
|
rlim = current->signal->rlim;
|
|
if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
|
|
put_page(page);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
return page;
|
|
}
|
|
|
|
static void put_arg_page(struct page *page)
|
|
{
|
|
put_page(page);
|
|
}
|
|
|
|
static void free_arg_page(struct linux_binprm *bprm, int i)
|
|
{
|
|
}
|
|
|
|
static void free_arg_pages(struct linux_binprm *bprm)
|
|
{
|
|
}
|
|
|
|
static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
|
|
struct page *page)
|
|
{
|
|
flush_cache_page(bprm->vma, pos, page_to_pfn(page));
|
|
}
|
|
|
|
static int __bprm_mm_init(struct linux_binprm *bprm)
|
|
{
|
|
int err;
|
|
struct vm_area_struct *vma = NULL;
|
|
struct mm_struct *mm = bprm->mm;
|
|
|
|
bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
|
|
if (!vma)
|
|
return -ENOMEM;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
vma->vm_mm = mm;
|
|
|
|
/*
|
|
* Place the stack at the largest stack address the architecture
|
|
* supports. Later, we'll move this to an appropriate place. We don't
|
|
* use STACK_TOP because that can depend on attributes which aren't
|
|
* configured yet.
|
|
*/
|
|
BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
|
|
vma->vm_end = STACK_TOP_MAX;
|
|
vma->vm_start = vma->vm_end - PAGE_SIZE;
|
|
vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
|
|
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
|
|
INIT_LIST_HEAD(&vma->anon_vma_chain);
|
|
|
|
err = insert_vm_struct(mm, vma);
|
|
if (err)
|
|
goto err;
|
|
|
|
mm->stack_vm = mm->total_vm = 1;
|
|
arch_bprm_mm_init(mm, vma);
|
|
up_write(&mm->mmap_sem);
|
|
bprm->p = vma->vm_end - sizeof(void *);
|
|
return 0;
|
|
err:
|
|
up_write(&mm->mmap_sem);
|
|
bprm->vma = NULL;
|
|
kmem_cache_free(vm_area_cachep, vma);
|
|
return err;
|
|
}
|
|
|
|
static bool valid_arg_len(struct linux_binprm *bprm, long len)
|
|
{
|
|
return len <= MAX_ARG_STRLEN;
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
|
|
{
|
|
}
|
|
|
|
static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
|
|
int write)
|
|
{
|
|
struct page *page;
|
|
|
|
page = bprm->page[pos / PAGE_SIZE];
|
|
if (!page && write) {
|
|
page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
|
|
if (!page)
|
|
return NULL;
|
|
bprm->page[pos / PAGE_SIZE] = page;
|
|
}
|
|
|
|
return page;
|
|
}
|
|
|
|
static void put_arg_page(struct page *page)
|
|
{
|
|
}
|
|
|
|
static void free_arg_page(struct linux_binprm *bprm, int i)
|
|
{
|
|
if (bprm->page[i]) {
|
|
__free_page(bprm->page[i]);
|
|
bprm->page[i] = NULL;
|
|
}
|
|
}
|
|
|
|
static void free_arg_pages(struct linux_binprm *bprm)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < MAX_ARG_PAGES; i++)
|
|
free_arg_page(bprm, i);
|
|
}
|
|
|
|
static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
|
|
struct page *page)
|
|
{
|
|
}
|
|
|
|
static int __bprm_mm_init(struct linux_binprm *bprm)
|
|
{
|
|
bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
|
|
return 0;
|
|
}
|
|
|
|
static bool valid_arg_len(struct linux_binprm *bprm, long len)
|
|
{
|
|
return len <= bprm->p;
|
|
}
|
|
|
|
#endif /* CONFIG_MMU */
|
|
|
|
/*
|
|
* Create a new mm_struct and populate it with a temporary stack
|
|
* vm_area_struct. We don't have enough context at this point to set the stack
|
|
* flags, permissions, and offset, so we use temporary values. We'll update
|
|
* them later in setup_arg_pages().
|
|
*/
|
|
static int bprm_mm_init(struct linux_binprm *bprm)
|
|
{
|
|
int err;
|
|
struct mm_struct *mm = NULL;
|
|
|
|
bprm->mm = mm = mm_alloc();
|
|
err = -ENOMEM;
|
|
if (!mm)
|
|
goto err;
|
|
|
|
err = __bprm_mm_init(bprm);
|
|
if (err)
|
|
goto err;
|
|
|
|
return 0;
|
|
|
|
err:
|
|
if (mm) {
|
|
bprm->mm = NULL;
|
|
mmdrop(mm);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
struct user_arg_ptr {
|
|
#ifdef CONFIG_COMPAT
|
|
bool is_compat;
|
|
#endif
|
|
union {
|
|
const char __user *const __user *native;
|
|
#ifdef CONFIG_COMPAT
|
|
const compat_uptr_t __user *compat;
|
|
#endif
|
|
} ptr;
|
|
};
|
|
|
|
static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
|
|
{
|
|
const char __user *native;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (unlikely(argv.is_compat)) {
|
|
compat_uptr_t compat;
|
|
|
|
if (get_user(compat, argv.ptr.compat + nr))
|
|
return ERR_PTR(-EFAULT);
|
|
|
|
return compat_ptr(compat);
|
|
}
|
|
#endif
|
|
|
|
if (get_user(native, argv.ptr.native + nr))
|
|
return ERR_PTR(-EFAULT);
|
|
|
|
return native;
|
|
}
|
|
|
|
/*
|
|
* count() counts the number of strings in array ARGV.
|
|
*/
|
|
static int count(struct user_arg_ptr argv, int max)
|
|
{
|
|
int i = 0;
|
|
|
|
if (argv.ptr.native != NULL) {
|
|
for (;;) {
|
|
const char __user *p = get_user_arg_ptr(argv, i);
|
|
|
|
if (!p)
|
|
break;
|
|
|
|
if (IS_ERR(p))
|
|
return -EFAULT;
|
|
|
|
if (i >= max)
|
|
return -E2BIG;
|
|
++i;
|
|
|
|
if (fatal_signal_pending(current))
|
|
return -ERESTARTNOHAND;
|
|
cond_resched();
|
|
}
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/*
|
|
* 'copy_strings()' copies argument/environment strings from the old
|
|
* processes's memory to the new process's stack. The call to get_user_pages()
|
|
* ensures the destination page is created and not swapped out.
|
|
*/
|
|
static int copy_strings(int argc, struct user_arg_ptr argv,
|
|
struct linux_binprm *bprm)
|
|
{
|
|
struct page *kmapped_page = NULL;
|
|
char *kaddr = NULL;
|
|
unsigned long kpos = 0;
|
|
int ret;
|
|
|
|
while (argc-- > 0) {
|
|
const char __user *str;
|
|
int len;
|
|
unsigned long pos;
|
|
|
|
ret = -EFAULT;
|
|
str = get_user_arg_ptr(argv, argc);
|
|
if (IS_ERR(str))
|
|
goto out;
|
|
|
|
len = strnlen_user(str, MAX_ARG_STRLEN);
|
|
if (!len)
|
|
goto out;
|
|
|
|
ret = -E2BIG;
|
|
if (!valid_arg_len(bprm, len))
|
|
goto out;
|
|
|
|
/* We're going to work our way backwords. */
|
|
pos = bprm->p;
|
|
str += len;
|
|
bprm->p -= len;
|
|
|
|
while (len > 0) {
|
|
int offset, bytes_to_copy;
|
|
|
|
if (fatal_signal_pending(current)) {
|
|
ret = -ERESTARTNOHAND;
|
|
goto out;
|
|
}
|
|
cond_resched();
|
|
|
|
offset = pos % PAGE_SIZE;
|
|
if (offset == 0)
|
|
offset = PAGE_SIZE;
|
|
|
|
bytes_to_copy = offset;
|
|
if (bytes_to_copy > len)
|
|
bytes_to_copy = len;
|
|
|
|
offset -= bytes_to_copy;
|
|
pos -= bytes_to_copy;
|
|
str -= bytes_to_copy;
|
|
len -= bytes_to_copy;
|
|
|
|
if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
|
|
struct page *page;
|
|
|
|
page = get_arg_page(bprm, pos, 1);
|
|
if (!page) {
|
|
ret = -E2BIG;
|
|
goto out;
|
|
}
|
|
|
|
if (kmapped_page) {
|
|
flush_kernel_dcache_page(kmapped_page);
|
|
kunmap(kmapped_page);
|
|
put_arg_page(kmapped_page);
|
|
}
|
|
kmapped_page = page;
|
|
kaddr = kmap(kmapped_page);
|
|
kpos = pos & PAGE_MASK;
|
|
flush_arg_page(bprm, kpos, kmapped_page);
|
|
}
|
|
if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
ret = 0;
|
|
out:
|
|
if (kmapped_page) {
|
|
flush_kernel_dcache_page(kmapped_page);
|
|
kunmap(kmapped_page);
|
|
put_arg_page(kmapped_page);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Like copy_strings, but get argv and its values from kernel memory.
|
|
*/
|
|
int copy_strings_kernel(int argc, const char *const *__argv,
|
|
struct linux_binprm *bprm)
|
|
{
|
|
int r;
|
|
mm_segment_t oldfs = get_fs();
|
|
struct user_arg_ptr argv = {
|
|
.ptr.native = (const char __user *const __user *)__argv,
|
|
};
|
|
|
|
set_fs(KERNEL_DS);
|
|
r = copy_strings(argc, argv, bprm);
|
|
set_fs(oldfs);
|
|
|
|
return r;
|
|
}
|
|
EXPORT_SYMBOL(copy_strings_kernel);
|
|
|
|
#ifdef CONFIG_MMU
|
|
|
|
/*
|
|
* During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
|
|
* the binfmt code determines where the new stack should reside, we shift it to
|
|
* its final location. The process proceeds as follows:
|
|
*
|
|
* 1) Use shift to calculate the new vma endpoints.
|
|
* 2) Extend vma to cover both the old and new ranges. This ensures the
|
|
* arguments passed to subsequent functions are consistent.
|
|
* 3) Move vma's page tables to the new range.
|
|
* 4) Free up any cleared pgd range.
|
|
* 5) Shrink the vma to cover only the new range.
|
|
*/
|
|
static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
unsigned long old_start = vma->vm_start;
|
|
unsigned long old_end = vma->vm_end;
|
|
unsigned long length = old_end - old_start;
|
|
unsigned long new_start = old_start - shift;
|
|
unsigned long new_end = old_end - shift;
|
|
struct mmu_gather tlb;
|
|
|
|
BUG_ON(new_start > new_end);
|
|
|
|
/*
|
|
* ensure there are no vmas between where we want to go
|
|
* and where we are
|
|
*/
|
|
if (vma != find_vma(mm, new_start))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* cover the whole range: [new_start, old_end)
|
|
*/
|
|
if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* move the page tables downwards, on failure we rely on
|
|
* process cleanup to remove whatever mess we made.
|
|
*/
|
|
if (length != move_page_tables(vma, old_start,
|
|
vma, new_start, length, false))
|
|
return -ENOMEM;
|
|
|
|
lru_add_drain();
|
|
tlb_gather_mmu(&tlb, mm, old_start, old_end);
|
|
if (new_end > old_start) {
|
|
/*
|
|
* when the old and new regions overlap clear from new_end.
|
|
*/
|
|
free_pgd_range(&tlb, new_end, old_end, new_end,
|
|
vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
|
|
} else {
|
|
/*
|
|
* otherwise, clean from old_start; this is done to not touch
|
|
* the address space in [new_end, old_start) some architectures
|
|
* have constraints on va-space that make this illegal (IA64) -
|
|
* for the others its just a little faster.
|
|
*/
|
|
free_pgd_range(&tlb, old_start, old_end, new_end,
|
|
vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
|
|
}
|
|
tlb_finish_mmu(&tlb, old_start, old_end);
|
|
|
|
/*
|
|
* Shrink the vma to just the new range. Always succeeds.
|
|
*/
|
|
vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Finalizes the stack vm_area_struct. The flags and permissions are updated,
|
|
* the stack is optionally relocated, and some extra space is added.
|
|
*/
|
|
int setup_arg_pages(struct linux_binprm *bprm,
|
|
unsigned long stack_top,
|
|
int executable_stack)
|
|
{
|
|
unsigned long ret;
|
|
unsigned long stack_shift;
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma = bprm->vma;
|
|
struct vm_area_struct *prev = NULL;
|
|
unsigned long vm_flags;
|
|
unsigned long stack_base;
|
|
unsigned long stack_size;
|
|
unsigned long stack_expand;
|
|
unsigned long rlim_stack;
|
|
|
|
#ifdef CONFIG_STACK_GROWSUP
|
|
/* Limit stack size */
|
|
stack_base = rlimit_max(RLIMIT_STACK);
|
|
if (stack_base > STACK_SIZE_MAX)
|
|
stack_base = STACK_SIZE_MAX;
|
|
|
|
/* Add space for stack randomization. */
|
|
stack_base += (STACK_RND_MASK << PAGE_SHIFT);
|
|
|
|
/* Make sure we didn't let the argument array grow too large. */
|
|
if (vma->vm_end - vma->vm_start > stack_base)
|
|
return -ENOMEM;
|
|
|
|
stack_base = PAGE_ALIGN(stack_top - stack_base);
|
|
|
|
stack_shift = vma->vm_start - stack_base;
|
|
mm->arg_start = bprm->p - stack_shift;
|
|
bprm->p = vma->vm_end - stack_shift;
|
|
#else
|
|
stack_top = arch_align_stack(stack_top);
|
|
stack_top = PAGE_ALIGN(stack_top);
|
|
|
|
if (unlikely(stack_top < mmap_min_addr) ||
|
|
unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
|
|
return -ENOMEM;
|
|
|
|
stack_shift = vma->vm_end - stack_top;
|
|
|
|
bprm->p -= stack_shift;
|
|
mm->arg_start = bprm->p;
|
|
#endif
|
|
|
|
if (bprm->loader)
|
|
bprm->loader -= stack_shift;
|
|
bprm->exec -= stack_shift;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
vm_flags = VM_STACK_FLAGS;
|
|
|
|
/*
|
|
* Adjust stack execute permissions; explicitly enable for
|
|
* EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
|
|
* (arch default) otherwise.
|
|
*/
|
|
if (unlikely(executable_stack == EXSTACK_ENABLE_X))
|
|
vm_flags |= VM_EXEC;
|
|
else if (executable_stack == EXSTACK_DISABLE_X)
|
|
vm_flags &= ~VM_EXEC;
|
|
vm_flags |= mm->def_flags;
|
|
vm_flags |= VM_STACK_INCOMPLETE_SETUP;
|
|
|
|
ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
|
|
vm_flags);
|
|
if (ret)
|
|
goto out_unlock;
|
|
BUG_ON(prev != vma);
|
|
|
|
/* Move stack pages down in memory. */
|
|
if (stack_shift) {
|
|
ret = shift_arg_pages(vma, stack_shift);
|
|
if (ret)
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* mprotect_fixup is overkill to remove the temporary stack flags */
|
|
vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP;
|
|
|
|
stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
|
|
stack_size = vma->vm_end - vma->vm_start;
|
|
/*
|
|
* Align this down to a page boundary as expand_stack
|
|
* will align it up.
|
|
*/
|
|
rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK;
|
|
#ifdef CONFIG_STACK_GROWSUP
|
|
if (stack_size + stack_expand > rlim_stack)
|
|
stack_base = vma->vm_start + rlim_stack;
|
|
else
|
|
stack_base = vma->vm_end + stack_expand;
|
|
#else
|
|
if (stack_size + stack_expand > rlim_stack)
|
|
stack_base = vma->vm_end - rlim_stack;
|
|
else
|
|
stack_base = vma->vm_start - stack_expand;
|
|
#endif
|
|
current->mm->start_stack = bprm->p;
|
|
ret = expand_stack(vma, stack_base);
|
|
if (ret)
|
|
ret = -EFAULT;
|
|
|
|
out_unlock:
|
|
up_write(&mm->mmap_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(setup_arg_pages);
|
|
|
|
#endif /* CONFIG_MMU */
|
|
|
|
static struct file *do_open_execat(int fd, struct filename *name, int flags)
|
|
{
|
|
struct file *file;
|
|
int err;
|
|
struct open_flags open_exec_flags = {
|
|
.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
|
|
.acc_mode = MAY_EXEC,
|
|
.intent = LOOKUP_OPEN,
|
|
.lookup_flags = LOOKUP_FOLLOW,
|
|
};
|
|
|
|
if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
|
|
return ERR_PTR(-EINVAL);
|
|
if (flags & AT_SYMLINK_NOFOLLOW)
|
|
open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
|
|
if (flags & AT_EMPTY_PATH)
|
|
open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
|
|
|
|
file = do_filp_open(fd, name, &open_exec_flags);
|
|
if (IS_ERR(file))
|
|
goto out;
|
|
|
|
err = -EACCES;
|
|
if (!S_ISREG(file_inode(file)->i_mode))
|
|
goto exit;
|
|
|
|
if (path_noexec(&file->f_path))
|
|
goto exit;
|
|
|
|
err = deny_write_access(file);
|
|
if (err)
|
|
goto exit;
|
|
|
|
if (name->name[0] != '\0')
|
|
fsnotify_open(file);
|
|
|
|
out:
|
|
return file;
|
|
|
|
exit:
|
|
fput(file);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
struct file *open_exec(const char *name)
|
|
{
|
|
struct filename *filename = getname_kernel(name);
|
|
struct file *f = ERR_CAST(filename);
|
|
|
|
if (!IS_ERR(filename)) {
|
|
f = do_open_execat(AT_FDCWD, filename, 0);
|
|
putname(filename);
|
|
}
|
|
return f;
|
|
}
|
|
EXPORT_SYMBOL(open_exec);
|
|
|
|
int kernel_read(struct file *file, loff_t offset,
|
|
char *addr, unsigned long count)
|
|
{
|
|
mm_segment_t old_fs;
|
|
loff_t pos = offset;
|
|
int result;
|
|
|
|
old_fs = get_fs();
|
|
set_fs(get_ds());
|
|
/* The cast to a user pointer is valid due to the set_fs() */
|
|
result = vfs_read(file, (void __user *)addr, count, &pos);
|
|
set_fs(old_fs);
|
|
return result;
|
|
}
|
|
|
|
EXPORT_SYMBOL(kernel_read);
|
|
|
|
int kernel_read_file(struct file *file, void **buf, loff_t *size,
|
|
loff_t max_size, enum kernel_read_file_id id)
|
|
{
|
|
loff_t i_size, pos;
|
|
ssize_t bytes = 0;
|
|
int ret;
|
|
|
|
if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
|
|
return -EINVAL;
|
|
|
|
ret = security_kernel_read_file(file, id);
|
|
if (ret)
|
|
return ret;
|
|
|
|
i_size = i_size_read(file_inode(file));
|
|
if (max_size > 0 && i_size > max_size)
|
|
return -EFBIG;
|
|
if (i_size <= 0)
|
|
return -EINVAL;
|
|
|
|
*buf = vmalloc(i_size);
|
|
if (!*buf)
|
|
return -ENOMEM;
|
|
|
|
pos = 0;
|
|
while (pos < i_size) {
|
|
bytes = kernel_read(file, pos, (char *)(*buf) + pos,
|
|
i_size - pos);
|
|
if (bytes < 0) {
|
|
ret = bytes;
|
|
goto out;
|
|
}
|
|
|
|
if (bytes == 0)
|
|
break;
|
|
pos += bytes;
|
|
}
|
|
|
|
if (pos != i_size) {
|
|
ret = -EIO;
|
|
goto out;
|
|
}
|
|
|
|
ret = security_kernel_post_read_file(file, *buf, i_size, id);
|
|
if (!ret)
|
|
*size = pos;
|
|
|
|
out:
|
|
if (ret < 0) {
|
|
vfree(*buf);
|
|
*buf = NULL;
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernel_read_file);
|
|
|
|
int kernel_read_file_from_path(char *path, void **buf, loff_t *size,
|
|
loff_t max_size, enum kernel_read_file_id id)
|
|
{
|
|
struct file *file;
|
|
int ret;
|
|
|
|
if (!path || !*path)
|
|
return -EINVAL;
|
|
|
|
file = filp_open(path, O_RDONLY, 0);
|
|
if (IS_ERR(file))
|
|
return PTR_ERR(file);
|
|
|
|
ret = kernel_read_file(file, buf, size, max_size, id);
|
|
fput(file);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
|
|
|
|
int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
|
|
enum kernel_read_file_id id)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int ret = -EBADF;
|
|
|
|
if (!f.file)
|
|
goto out;
|
|
|
|
ret = kernel_read_file(f.file, buf, size, max_size, id);
|
|
out:
|
|
fdput(f);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
|
|
|
|
ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
|
|
{
|
|
ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
|
|
if (res > 0)
|
|
flush_icache_range(addr, addr + len);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(read_code);
|
|
|
|
static int exec_mmap(struct mm_struct *mm)
|
|
{
|
|
struct task_struct *tsk;
|
|
struct mm_struct *old_mm, *active_mm;
|
|
|
|
/* Notify parent that we're no longer interested in the old VM */
|
|
tsk = current;
|
|
old_mm = current->mm;
|
|
mm_release(tsk, old_mm);
|
|
|
|
if (old_mm) {
|
|
sync_mm_rss(old_mm);
|
|
/*
|
|
* Make sure that if there is a core dump in progress
|
|
* for the old mm, we get out and die instead of going
|
|
* through with the exec. We must hold mmap_sem around
|
|
* checking core_state and changing tsk->mm.
|
|
*/
|
|
down_read(&old_mm->mmap_sem);
|
|
if (unlikely(old_mm->core_state)) {
|
|
up_read(&old_mm->mmap_sem);
|
|
return -EINTR;
|
|
}
|
|
}
|
|
task_lock(tsk);
|
|
active_mm = tsk->active_mm;
|
|
tsk->mm = mm;
|
|
tsk->active_mm = mm;
|
|
activate_mm(active_mm, mm);
|
|
tsk->mm->vmacache_seqnum = 0;
|
|
vmacache_flush(tsk);
|
|
task_unlock(tsk);
|
|
if (old_mm) {
|
|
up_read(&old_mm->mmap_sem);
|
|
BUG_ON(active_mm != old_mm);
|
|
setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm);
|
|
mm_update_next_owner(old_mm);
|
|
mmput(old_mm);
|
|
return 0;
|
|
}
|
|
mmdrop(active_mm);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function makes sure the current process has its own signal table,
|
|
* so that flush_signal_handlers can later reset the handlers without
|
|
* disturbing other processes. (Other processes might share the signal
|
|
* table via the CLONE_SIGHAND option to clone().)
|
|
*/
|
|
static int de_thread(struct task_struct *tsk)
|
|
{
|
|
struct signal_struct *sig = tsk->signal;
|
|
struct sighand_struct *oldsighand = tsk->sighand;
|
|
spinlock_t *lock = &oldsighand->siglock;
|
|
|
|
if (thread_group_empty(tsk))
|
|
goto no_thread_group;
|
|
|
|
/*
|
|
* Kill all other threads in the thread group.
|
|
*/
|
|
spin_lock_irq(lock);
|
|
if (signal_group_exit(sig)) {
|
|
/*
|
|
* Another group action in progress, just
|
|
* return so that the signal is processed.
|
|
*/
|
|
spin_unlock_irq(lock);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
sig->group_exit_task = tsk;
|
|
sig->notify_count = zap_other_threads(tsk);
|
|
if (!thread_group_leader(tsk))
|
|
sig->notify_count--;
|
|
|
|
while (sig->notify_count) {
|
|
__set_current_state(TASK_KILLABLE);
|
|
spin_unlock_irq(lock);
|
|
schedule();
|
|
if (unlikely(__fatal_signal_pending(tsk)))
|
|
goto killed;
|
|
spin_lock_irq(lock);
|
|
}
|
|
spin_unlock_irq(lock);
|
|
|
|
/*
|
|
* At this point all other threads have exited, all we have to
|
|
* do is to wait for the thread group leader to become inactive,
|
|
* and to assume its PID:
|
|
*/
|
|
if (!thread_group_leader(tsk)) {
|
|
struct task_struct *leader = tsk->group_leader;
|
|
|
|
for (;;) {
|
|
threadgroup_change_begin(tsk);
|
|
write_lock_irq(&tasklist_lock);
|
|
/*
|
|
* Do this under tasklist_lock to ensure that
|
|
* exit_notify() can't miss ->group_exit_task
|
|
*/
|
|
sig->notify_count = -1;
|
|
if (likely(leader->exit_state))
|
|
break;
|
|
__set_current_state(TASK_KILLABLE);
|
|
write_unlock_irq(&tasklist_lock);
|
|
threadgroup_change_end(tsk);
|
|
schedule();
|
|
if (unlikely(__fatal_signal_pending(tsk)))
|
|
goto killed;
|
|
}
|
|
|
|
/*
|
|
* The only record we have of the real-time age of a
|
|
* process, regardless of execs it's done, is start_time.
|
|
* All the past CPU time is accumulated in signal_struct
|
|
* from sister threads now dead. But in this non-leader
|
|
* exec, nothing survives from the original leader thread,
|
|
* whose birth marks the true age of this process now.
|
|
* When we take on its identity by switching to its PID, we
|
|
* also take its birthdate (always earlier than our own).
|
|
*/
|
|
tsk->start_time = leader->start_time;
|
|
tsk->real_start_time = leader->real_start_time;
|
|
|
|
BUG_ON(!same_thread_group(leader, tsk));
|
|
BUG_ON(has_group_leader_pid(tsk));
|
|
/*
|
|
* An exec() starts a new thread group with the
|
|
* TGID of the previous thread group. Rehash the
|
|
* two threads with a switched PID, and release
|
|
* the former thread group leader:
|
|
*/
|
|
|
|
/* Become a process group leader with the old leader's pid.
|
|
* The old leader becomes a thread of the this thread group.
|
|
* Note: The old leader also uses this pid until release_task
|
|
* is called. Odd but simple and correct.
|
|
*/
|
|
tsk->pid = leader->pid;
|
|
change_pid(tsk, PIDTYPE_PID, task_pid(leader));
|
|
transfer_pid(leader, tsk, PIDTYPE_PGID);
|
|
transfer_pid(leader, tsk, PIDTYPE_SID);
|
|
|
|
list_replace_rcu(&leader->tasks, &tsk->tasks);
|
|
list_replace_init(&leader->sibling, &tsk->sibling);
|
|
|
|
tsk->group_leader = tsk;
|
|
leader->group_leader = tsk;
|
|
|
|
tsk->exit_signal = SIGCHLD;
|
|
leader->exit_signal = -1;
|
|
|
|
BUG_ON(leader->exit_state != EXIT_ZOMBIE);
|
|
leader->exit_state = EXIT_DEAD;
|
|
|
|
/*
|
|
* We are going to release_task()->ptrace_unlink() silently,
|
|
* the tracer can sleep in do_wait(). EXIT_DEAD guarantees
|
|
* the tracer wont't block again waiting for this thread.
|
|
*/
|
|
if (unlikely(leader->ptrace))
|
|
__wake_up_parent(leader, leader->parent);
|
|
write_unlock_irq(&tasklist_lock);
|
|
threadgroup_change_end(tsk);
|
|
|
|
release_task(leader);
|
|
}
|
|
|
|
sig->group_exit_task = NULL;
|
|
sig->notify_count = 0;
|
|
|
|
no_thread_group:
|
|
/* we have changed execution domain */
|
|
tsk->exit_signal = SIGCHLD;
|
|
|
|
exit_itimers(sig);
|
|
flush_itimer_signals();
|
|
|
|
if (atomic_read(&oldsighand->count) != 1) {
|
|
struct sighand_struct *newsighand;
|
|
/*
|
|
* This ->sighand is shared with the CLONE_SIGHAND
|
|
* but not CLONE_THREAD task, switch to the new one.
|
|
*/
|
|
newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
|
|
if (!newsighand)
|
|
return -ENOMEM;
|
|
|
|
atomic_set(&newsighand->count, 1);
|
|
memcpy(newsighand->action, oldsighand->action,
|
|
sizeof(newsighand->action));
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
spin_lock(&oldsighand->siglock);
|
|
rcu_assign_pointer(tsk->sighand, newsighand);
|
|
spin_unlock(&oldsighand->siglock);
|
|
write_unlock_irq(&tasklist_lock);
|
|
|
|
__cleanup_sighand(oldsighand);
|
|
}
|
|
|
|
BUG_ON(!thread_group_leader(tsk));
|
|
return 0;
|
|
|
|
killed:
|
|
/* protects against exit_notify() and __exit_signal() */
|
|
read_lock(&tasklist_lock);
|
|
sig->group_exit_task = NULL;
|
|
sig->notify_count = 0;
|
|
read_unlock(&tasklist_lock);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
char *get_task_comm(char *buf, struct task_struct *tsk)
|
|
{
|
|
/* buf must be at least sizeof(tsk->comm) in size */
|
|
task_lock(tsk);
|
|
strncpy(buf, tsk->comm, sizeof(tsk->comm));
|
|
task_unlock(tsk);
|
|
return buf;
|
|
}
|
|
EXPORT_SYMBOL_GPL(get_task_comm);
|
|
|
|
/*
|
|
* These functions flushes out all traces of the currently running executable
|
|
* so that a new one can be started
|
|
*/
|
|
|
|
void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
|
|
{
|
|
task_lock(tsk);
|
|
trace_task_rename(tsk, buf);
|
|
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
|
|
task_unlock(tsk);
|
|
perf_event_comm(tsk, exec);
|
|
}
|
|
|
|
int flush_old_exec(struct linux_binprm * bprm)
|
|
{
|
|
int retval;
|
|
|
|
/*
|
|
* Make sure we have a private signal table and that
|
|
* we are unassociated from the previous thread group.
|
|
*/
|
|
retval = de_thread(current);
|
|
if (retval)
|
|
goto out;
|
|
|
|
/*
|
|
* Must be called _before_ exec_mmap() as bprm->mm is
|
|
* not visibile until then. This also enables the update
|
|
* to be lockless.
|
|
*/
|
|
set_mm_exe_file(bprm->mm, bprm->file);
|
|
|
|
/*
|
|
* Release all of the old mmap stuff
|
|
*/
|
|
acct_arg_size(bprm, 0);
|
|
retval = exec_mmap(bprm->mm);
|
|
if (retval)
|
|
goto out;
|
|
|
|
bprm->mm = NULL; /* We're using it now */
|
|
|
|
set_fs(USER_DS);
|
|
current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
|
|
PF_NOFREEZE | PF_NO_SETAFFINITY);
|
|
flush_thread();
|
|
current->personality &= ~bprm->per_clear;
|
|
|
|
return 0;
|
|
|
|
out:
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL(flush_old_exec);
|
|
|
|
void would_dump(struct linux_binprm *bprm, struct file *file)
|
|
{
|
|
if (inode_permission(file_inode(file), MAY_READ) < 0)
|
|
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
|
|
}
|
|
EXPORT_SYMBOL(would_dump);
|
|
|
|
void setup_new_exec(struct linux_binprm * bprm)
|
|
{
|
|
arch_pick_mmap_layout(current->mm);
|
|
|
|
/* This is the point of no return */
|
|
current->sas_ss_sp = current->sas_ss_size = 0;
|
|
|
|
if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
|
|
set_dumpable(current->mm, SUID_DUMP_USER);
|
|
else
|
|
set_dumpable(current->mm, suid_dumpable);
|
|
|
|
perf_event_exec();
|
|
__set_task_comm(current, kbasename(bprm->filename), true);
|
|
|
|
/* Set the new mm task size. We have to do that late because it may
|
|
* depend on TIF_32BIT which is only updated in flush_thread() on
|
|
* some architectures like powerpc
|
|
*/
|
|
current->mm->task_size = TASK_SIZE;
|
|
|
|
/* install the new credentials */
|
|
if (!uid_eq(bprm->cred->uid, current_euid()) ||
|
|
!gid_eq(bprm->cred->gid, current_egid())) {
|
|
current->pdeath_signal = 0;
|
|
} else {
|
|
would_dump(bprm, bprm->file);
|
|
if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
|
|
set_dumpable(current->mm, suid_dumpable);
|
|
}
|
|
|
|
/* An exec changes our domain. We are no longer part of the thread
|
|
group */
|
|
current->self_exec_id++;
|
|
flush_signal_handlers(current, 0);
|
|
do_close_on_exec(current->files);
|
|
}
|
|
EXPORT_SYMBOL(setup_new_exec);
|
|
|
|
/*
|
|
* Prepare credentials and lock ->cred_guard_mutex.
|
|
* install_exec_creds() commits the new creds and drops the lock.
|
|
* Or, if exec fails before, free_bprm() should release ->cred and
|
|
* and unlock.
|
|
*/
|
|
int prepare_bprm_creds(struct linux_binprm *bprm)
|
|
{
|
|
if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex))
|
|
return -ERESTARTNOINTR;
|
|
|
|
bprm->cred = prepare_exec_creds();
|
|
if (likely(bprm->cred))
|
|
return 0;
|
|
|
|
mutex_unlock(¤t->signal->cred_guard_mutex);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void free_bprm(struct linux_binprm *bprm)
|
|
{
|
|
free_arg_pages(bprm);
|
|
if (bprm->cred) {
|
|
mutex_unlock(¤t->signal->cred_guard_mutex);
|
|
abort_creds(bprm->cred);
|
|
}
|
|
if (bprm->file) {
|
|
allow_write_access(bprm->file);
|
|
fput(bprm->file);
|
|
}
|
|
/* If a binfmt changed the interp, free it. */
|
|
if (bprm->interp != bprm->filename)
|
|
kfree(bprm->interp);
|
|
kfree(bprm);
|
|
}
|
|
|
|
int bprm_change_interp(char *interp, struct linux_binprm *bprm)
|
|
{
|
|
/* If a binfmt changed the interp, free it first. */
|
|
if (bprm->interp != bprm->filename)
|
|
kfree(bprm->interp);
|
|
bprm->interp = kstrdup(interp, GFP_KERNEL);
|
|
if (!bprm->interp)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(bprm_change_interp);
|
|
|
|
/*
|
|
* install the new credentials for this executable
|
|
*/
|
|
void install_exec_creds(struct linux_binprm *bprm)
|
|
{
|
|
security_bprm_committing_creds(bprm);
|
|
|
|
commit_creds(bprm->cred);
|
|
bprm->cred = NULL;
|
|
|
|
/*
|
|
* Disable monitoring for regular users
|
|
* when executing setuid binaries. Must
|
|
* wait until new credentials are committed
|
|
* by commit_creds() above
|
|
*/
|
|
if (get_dumpable(current->mm) != SUID_DUMP_USER)
|
|
perf_event_exit_task(current);
|
|
/*
|
|
* cred_guard_mutex must be held at least to this point to prevent
|
|
* ptrace_attach() from altering our determination of the task's
|
|
* credentials; any time after this it may be unlocked.
|
|
*/
|
|
security_bprm_committed_creds(bprm);
|
|
mutex_unlock(¤t->signal->cred_guard_mutex);
|
|
}
|
|
EXPORT_SYMBOL(install_exec_creds);
|
|
|
|
/*
|
|
* determine how safe it is to execute the proposed program
|
|
* - the caller must hold ->cred_guard_mutex to protect against
|
|
* PTRACE_ATTACH or seccomp thread-sync
|
|
*/
|
|
static void check_unsafe_exec(struct linux_binprm *bprm)
|
|
{
|
|
struct task_struct *p = current, *t;
|
|
unsigned n_fs;
|
|
|
|
if (p->ptrace) {
|
|
if (p->ptrace & PT_PTRACE_CAP)
|
|
bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
|
|
else
|
|
bprm->unsafe |= LSM_UNSAFE_PTRACE;
|
|
}
|
|
|
|
/*
|
|
* This isn't strictly necessary, but it makes it harder for LSMs to
|
|
* mess up.
|
|
*/
|
|
if (task_no_new_privs(current))
|
|
bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
|
|
|
|
t = p;
|
|
n_fs = 1;
|
|
spin_lock(&p->fs->lock);
|
|
rcu_read_lock();
|
|
while_each_thread(p, t) {
|
|
if (t->fs == p->fs)
|
|
n_fs++;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (p->fs->users > n_fs)
|
|
bprm->unsafe |= LSM_UNSAFE_SHARE;
|
|
else
|
|
p->fs->in_exec = 1;
|
|
spin_unlock(&p->fs->lock);
|
|
}
|
|
|
|
static void bprm_fill_uid(struct linux_binprm *bprm)
|
|
{
|
|
struct inode *inode;
|
|
unsigned int mode;
|
|
kuid_t uid;
|
|
kgid_t gid;
|
|
|
|
/* clear any previous set[ug]id data from a previous binary */
|
|
bprm->cred->euid = current_euid();
|
|
bprm->cred->egid = current_egid();
|
|
|
|
if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
|
|
return;
|
|
|
|
if (task_no_new_privs(current))
|
|
return;
|
|
|
|
inode = file_inode(bprm->file);
|
|
mode = READ_ONCE(inode->i_mode);
|
|
if (!(mode & (S_ISUID|S_ISGID)))
|
|
return;
|
|
|
|
/* Be careful if suid/sgid is set */
|
|
inode_lock(inode);
|
|
|
|
/* reload atomically mode/uid/gid now that lock held */
|
|
mode = inode->i_mode;
|
|
uid = inode->i_uid;
|
|
gid = inode->i_gid;
|
|
inode_unlock(inode);
|
|
|
|
/* We ignore suid/sgid if there are no mappings for them in the ns */
|
|
if (!kuid_has_mapping(bprm->cred->user_ns, uid) ||
|
|
!kgid_has_mapping(bprm->cred->user_ns, gid))
|
|
return;
|
|
|
|
if (mode & S_ISUID) {
|
|
bprm->per_clear |= PER_CLEAR_ON_SETID;
|
|
bprm->cred->euid = uid;
|
|
}
|
|
|
|
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
|
|
bprm->per_clear |= PER_CLEAR_ON_SETID;
|
|
bprm->cred->egid = gid;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Fill the binprm structure from the inode.
|
|
* Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
|
|
*
|
|
* This may be called multiple times for binary chains (scripts for example).
|
|
*/
|
|
int prepare_binprm(struct linux_binprm *bprm)
|
|
{
|
|
int retval;
|
|
|
|
bprm_fill_uid(bprm);
|
|
|
|
/* fill in binprm security blob */
|
|
retval = security_bprm_set_creds(bprm);
|
|
if (retval)
|
|
return retval;
|
|
bprm->cred_prepared = 1;
|
|
|
|
memset(bprm->buf, 0, BINPRM_BUF_SIZE);
|
|
return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
|
|
}
|
|
|
|
EXPORT_SYMBOL(prepare_binprm);
|
|
|
|
/*
|
|
* Arguments are '\0' separated strings found at the location bprm->p
|
|
* points to; chop off the first by relocating brpm->p to right after
|
|
* the first '\0' encountered.
|
|
*/
|
|
int remove_arg_zero(struct linux_binprm *bprm)
|
|
{
|
|
int ret = 0;
|
|
unsigned long offset;
|
|
char *kaddr;
|
|
struct page *page;
|
|
|
|
if (!bprm->argc)
|
|
return 0;
|
|
|
|
do {
|
|
offset = bprm->p & ~PAGE_MASK;
|
|
page = get_arg_page(bprm, bprm->p, 0);
|
|
if (!page) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
kaddr = kmap_atomic(page);
|
|
|
|
for (; offset < PAGE_SIZE && kaddr[offset];
|
|
offset++, bprm->p++)
|
|
;
|
|
|
|
kunmap_atomic(kaddr);
|
|
put_arg_page(page);
|
|
|
|
if (offset == PAGE_SIZE)
|
|
free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
|
|
} while (offset == PAGE_SIZE);
|
|
|
|
bprm->p++;
|
|
bprm->argc--;
|
|
ret = 0;
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(remove_arg_zero);
|
|
|
|
#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
|
|
/*
|
|
* cycle the list of binary formats handler, until one recognizes the image
|
|
*/
|
|
int search_binary_handler(struct linux_binprm *bprm)
|
|
{
|
|
bool need_retry = IS_ENABLED(CONFIG_MODULES);
|
|
struct linux_binfmt *fmt;
|
|
int retval;
|
|
|
|
/* This allows 4 levels of binfmt rewrites before failing hard. */
|
|
if (bprm->recursion_depth > 5)
|
|
return -ELOOP;
|
|
|
|
retval = security_bprm_check(bprm);
|
|
if (retval)
|
|
return retval;
|
|
|
|
retval = -ENOENT;
|
|
retry:
|
|
read_lock(&binfmt_lock);
|
|
list_for_each_entry(fmt, &formats, lh) {
|
|
if (!try_module_get(fmt->module))
|
|
continue;
|
|
read_unlock(&binfmt_lock);
|
|
bprm->recursion_depth++;
|
|
retval = fmt->load_binary(bprm);
|
|
read_lock(&binfmt_lock);
|
|
put_binfmt(fmt);
|
|
bprm->recursion_depth--;
|
|
if (retval < 0 && !bprm->mm) {
|
|
/* we got to flush_old_exec() and failed after it */
|
|
read_unlock(&binfmt_lock);
|
|
force_sigsegv(SIGSEGV, current);
|
|
return retval;
|
|
}
|
|
if (retval != -ENOEXEC || !bprm->file) {
|
|
read_unlock(&binfmt_lock);
|
|
return retval;
|
|
}
|
|
}
|
|
read_unlock(&binfmt_lock);
|
|
|
|
if (need_retry) {
|
|
if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
|
|
printable(bprm->buf[2]) && printable(bprm->buf[3]))
|
|
return retval;
|
|
if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
|
|
return retval;
|
|
need_retry = false;
|
|
goto retry;
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL(search_binary_handler);
|
|
|
|
static int exec_binprm(struct linux_binprm *bprm)
|
|
{
|
|
pid_t old_pid, old_vpid;
|
|
int ret;
|
|
|
|
/* Need to fetch pid before load_binary changes it */
|
|
old_pid = current->pid;
|
|
rcu_read_lock();
|
|
old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
|
|
rcu_read_unlock();
|
|
|
|
ret = search_binary_handler(bprm);
|
|
if (ret >= 0) {
|
|
audit_bprm(bprm);
|
|
trace_sched_process_exec(current, old_pid, bprm);
|
|
ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
|
|
proc_exec_connector(current);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* sys_execve() executes a new program.
|
|
*/
|
|
static int do_execveat_common(int fd, struct filename *filename,
|
|
struct user_arg_ptr argv,
|
|
struct user_arg_ptr envp,
|
|
int flags)
|
|
{
|
|
char *pathbuf = NULL;
|
|
struct linux_binprm *bprm;
|
|
struct file *file;
|
|
struct files_struct *displaced;
|
|
int retval;
|
|
|
|
if (IS_ERR(filename))
|
|
return PTR_ERR(filename);
|
|
|
|
/*
|
|
* We move the actual failure in case of RLIMIT_NPROC excess from
|
|
* set*uid() to execve() because too many poorly written programs
|
|
* don't check setuid() return code. Here we additionally recheck
|
|
* whether NPROC limit is still exceeded.
|
|
*/
|
|
if ((current->flags & PF_NPROC_EXCEEDED) &&
|
|
atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) {
|
|
retval = -EAGAIN;
|
|
goto out_ret;
|
|
}
|
|
|
|
/* We're below the limit (still or again), so we don't want to make
|
|
* further execve() calls fail. */
|
|
current->flags &= ~PF_NPROC_EXCEEDED;
|
|
|
|
retval = unshare_files(&displaced);
|
|
if (retval)
|
|
goto out_ret;
|
|
|
|
retval = -ENOMEM;
|
|
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
|
|
if (!bprm)
|
|
goto out_files;
|
|
|
|
retval = prepare_bprm_creds(bprm);
|
|
if (retval)
|
|
goto out_free;
|
|
|
|
check_unsafe_exec(bprm);
|
|
current->in_execve = 1;
|
|
|
|
file = do_open_execat(fd, filename, flags);
|
|
retval = PTR_ERR(file);
|
|
if (IS_ERR(file))
|
|
goto out_unmark;
|
|
|
|
sched_exec();
|
|
|
|
bprm->file = file;
|
|
if (fd == AT_FDCWD || filename->name[0] == '/') {
|
|
bprm->filename = filename->name;
|
|
} else {
|
|
if (filename->name[0] == '\0')
|
|
pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd);
|
|
else
|
|
pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s",
|
|
fd, filename->name);
|
|
if (!pathbuf) {
|
|
retval = -ENOMEM;
|
|
goto out_unmark;
|
|
}
|
|
/*
|
|
* Record that a name derived from an O_CLOEXEC fd will be
|
|
* inaccessible after exec. Relies on having exclusive access to
|
|
* current->files (due to unshare_files above).
|
|
*/
|
|
if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt)))
|
|
bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
|
|
bprm->filename = pathbuf;
|
|
}
|
|
bprm->interp = bprm->filename;
|
|
|
|
retval = bprm_mm_init(bprm);
|
|
if (retval)
|
|
goto out_unmark;
|
|
|
|
bprm->argc = count(argv, MAX_ARG_STRINGS);
|
|
if ((retval = bprm->argc) < 0)
|
|
goto out;
|
|
|
|
bprm->envc = count(envp, MAX_ARG_STRINGS);
|
|
if ((retval = bprm->envc) < 0)
|
|
goto out;
|
|
|
|
retval = prepare_binprm(bprm);
|
|
if (retval < 0)
|
|
goto out;
|
|
|
|
retval = copy_strings_kernel(1, &bprm->filename, bprm);
|
|
if (retval < 0)
|
|
goto out;
|
|
|
|
bprm->exec = bprm->p;
|
|
retval = copy_strings(bprm->envc, envp, bprm);
|
|
if (retval < 0)
|
|
goto out;
|
|
|
|
retval = copy_strings(bprm->argc, argv, bprm);
|
|
if (retval < 0)
|
|
goto out;
|
|
|
|
retval = exec_binprm(bprm);
|
|
if (retval < 0)
|
|
goto out;
|
|
|
|
/* execve succeeded */
|
|
current->fs->in_exec = 0;
|
|
current->in_execve = 0;
|
|
acct_update_integrals(current);
|
|
task_numa_free(current);
|
|
free_bprm(bprm);
|
|
kfree(pathbuf);
|
|
putname(filename);
|
|
if (displaced)
|
|
put_files_struct(displaced);
|
|
return retval;
|
|
|
|
out:
|
|
if (bprm->mm) {
|
|
acct_arg_size(bprm, 0);
|
|
mmput(bprm->mm);
|
|
}
|
|
|
|
out_unmark:
|
|
current->fs->in_exec = 0;
|
|
current->in_execve = 0;
|
|
|
|
out_free:
|
|
free_bprm(bprm);
|
|
kfree(pathbuf);
|
|
|
|
out_files:
|
|
if (displaced)
|
|
reset_files_struct(displaced);
|
|
out_ret:
|
|
putname(filename);
|
|
return retval;
|
|
}
|
|
|
|
int do_execve(struct filename *filename,
|
|
const char __user *const __user *__argv,
|
|
const char __user *const __user *__envp)
|
|
{
|
|
struct user_arg_ptr argv = { .ptr.native = __argv };
|
|
struct user_arg_ptr envp = { .ptr.native = __envp };
|
|
return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
|
|
}
|
|
|
|
int do_execveat(int fd, struct filename *filename,
|
|
const char __user *const __user *__argv,
|
|
const char __user *const __user *__envp,
|
|
int flags)
|
|
{
|
|
struct user_arg_ptr argv = { .ptr.native = __argv };
|
|
struct user_arg_ptr envp = { .ptr.native = __envp };
|
|
|
|
return do_execveat_common(fd, filename, argv, envp, flags);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
static int compat_do_execve(struct filename *filename,
|
|
const compat_uptr_t __user *__argv,
|
|
const compat_uptr_t __user *__envp)
|
|
{
|
|
struct user_arg_ptr argv = {
|
|
.is_compat = true,
|
|
.ptr.compat = __argv,
|
|
};
|
|
struct user_arg_ptr envp = {
|
|
.is_compat = true,
|
|
.ptr.compat = __envp,
|
|
};
|
|
return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
|
|
}
|
|
|
|
static int compat_do_execveat(int fd, struct filename *filename,
|
|
const compat_uptr_t __user *__argv,
|
|
const compat_uptr_t __user *__envp,
|
|
int flags)
|
|
{
|
|
struct user_arg_ptr argv = {
|
|
.is_compat = true,
|
|
.ptr.compat = __argv,
|
|
};
|
|
struct user_arg_ptr envp = {
|
|
.is_compat = true,
|
|
.ptr.compat = __envp,
|
|
};
|
|
return do_execveat_common(fd, filename, argv, envp, flags);
|
|
}
|
|
#endif
|
|
|
|
void set_binfmt(struct linux_binfmt *new)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
if (mm->binfmt)
|
|
module_put(mm->binfmt->module);
|
|
|
|
mm->binfmt = new;
|
|
if (new)
|
|
__module_get(new->module);
|
|
}
|
|
EXPORT_SYMBOL(set_binfmt);
|
|
|
|
/*
|
|
* set_dumpable stores three-value SUID_DUMP_* into mm->flags.
|
|
*/
|
|
void set_dumpable(struct mm_struct *mm, int value)
|
|
{
|
|
unsigned long old, new;
|
|
|
|
if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
|
|
return;
|
|
|
|
do {
|
|
old = ACCESS_ONCE(mm->flags);
|
|
new = (old & ~MMF_DUMPABLE_MASK) | value;
|
|
} while (cmpxchg(&mm->flags, old, new) != old);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(execve,
|
|
const char __user *, filename,
|
|
const char __user *const __user *, argv,
|
|
const char __user *const __user *, envp)
|
|
{
|
|
return do_execve(getname(filename), argv, envp);
|
|
}
|
|
|
|
SYSCALL_DEFINE5(execveat,
|
|
int, fd, const char __user *, filename,
|
|
const char __user *const __user *, argv,
|
|
const char __user *const __user *, envp,
|
|
int, flags)
|
|
{
|
|
int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
|
|
|
|
return do_execveat(fd,
|
|
getname_flags(filename, lookup_flags, NULL),
|
|
argv, envp, flags);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
|
|
const compat_uptr_t __user *, argv,
|
|
const compat_uptr_t __user *, envp)
|
|
{
|
|
return compat_do_execve(getname(filename), argv, envp);
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
|
|
const char __user *, filename,
|
|
const compat_uptr_t __user *, argv,
|
|
const compat_uptr_t __user *, envp,
|
|
int, flags)
|
|
{
|
|
int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
|
|
|
|
return compat_do_execveat(fd,
|
|
getname_flags(filename, lookup_flags, NULL),
|
|
argv, envp, flags);
|
|
}
|
|
#endif
|