#include <linux/slab.h>
#include <linux/file.h>
-#include <linux/mman.h>
-#include <linux/a.out.h>
+#include <linux/fdtable.h>
+#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/smp_lock.h>
+#include <linux/swap.h>
+#include <linux/string.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/key.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
-#include <linux/swap.h>
#include <linux/utsname.h>
#include <linux/pid_namespace.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/proc_fs.h>
-#include <linux/ptrace.h>
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
-#include <linux/rmap.h>
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/audit.h>
-#include <linux/signalfd.h>
+#include <linux/tracehook.h>
+#include <linux/kmod.h>
+#include <linux/fsnotify.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
-
-#ifdef CONFIG_KMOD
-#include <linux/kmod.h>
-#endif
+#include <asm/tlb.h>
+#include "internal.h"
int core_uses_pid;
char core_pattern[CORENAME_MAX_SIZE] = "core";
int suid_dumpable = 0;
-EXPORT_SYMBOL(suid_dumpable);
/* The maximal length of core_pattern is also specified in sysctl.c */
-static struct linux_binfmt *formats;
+static LIST_HEAD(formats);
static DEFINE_RWLOCK(binfmt_lock);
int register_binfmt(struct linux_binfmt * fmt)
{
- struct linux_binfmt ** tmp = &formats;
-
if (!fmt)
return -EINVAL;
- if (fmt->next)
- return -EBUSY;
write_lock(&binfmt_lock);
- while (*tmp) {
- if (fmt == *tmp) {
- write_unlock(&binfmt_lock);
- return -EBUSY;
- }
- tmp = &(*tmp)->next;
- }
- fmt->next = formats;
- formats = fmt;
+ list_add(&fmt->lh, &formats);
write_unlock(&binfmt_lock);
return 0;
}
EXPORT_SYMBOL(register_binfmt);
-int unregister_binfmt(struct linux_binfmt * fmt)
+void unregister_binfmt(struct linux_binfmt * fmt)
{
- struct linux_binfmt ** tmp = &formats;
-
write_lock(&binfmt_lock);
- while (*tmp) {
- if (fmt == *tmp) {
- *tmp = fmt->next;
- fmt->next = NULL;
- write_unlock(&binfmt_lock);
- return 0;
- }
- tmp = &(*tmp)->next;
- }
+ list_del(&fmt->lh);
write_unlock(&binfmt_lock);
- return -EINVAL;
}
EXPORT_SYMBOL(unregister_binfmt);
*
* Also note that we take the address to load from from the file itself.
*/
-asmlinkage long sys_uselib(const char __user * library)
+SYSCALL_DEFINE1(uselib, const char __user *, library)
{
- struct file * file;
+ struct file *file;
struct nameidata nd;
- int error;
-
- error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
+ char *tmp = getname(library);
+ int error = PTR_ERR(tmp);
+
+ if (!IS_ERR(tmp)) {
+ error = path_lookup_open(AT_FDCWD, tmp,
+ LOOKUP_FOLLOW, &nd,
+ FMODE_READ|FMODE_EXEC);
+ putname(tmp);
+ }
if (error)
goto out;
- error = -EACCES;
- if (nd.mnt->mnt_flags & MNT_NOEXEC)
- goto exit;
error = -EINVAL;
- if (!S_ISREG(nd.dentry->d_inode->i_mode))
+ if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
+ goto exit;
+
+ error = -EACCES;
+ if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
goto exit;
- error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
+ error = inode_permission(nd.path.dentry->d_inode,
+ MAY_READ | MAY_EXEC | MAY_OPEN);
if (error)
goto exit;
- file = nameidata_to_filp(&nd, O_RDONLY);
+ file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
error = PTR_ERR(file);
if (IS_ERR(file))
goto out;
+ fsnotify_open(file->f_path.dentry);
+
error = -ENOEXEC;
if(file->f_op) {
struct linux_binfmt * fmt;
read_lock(&binfmt_lock);
- for (fmt = formats ; fmt ; fmt = fmt->next) {
+ list_for_each_entry(fmt, &formats, lh) {
if (!fmt->load_shlib)
continue;
if (!try_module_get(fmt->module))
return error;
exit:
release_open_intent(&nd);
- path_release(&nd);
+ path_put(&nd.path);
goto out;
}
+#ifdef CONFIG_MMU
+
+static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
+ int write)
+{
+ struct page *page;
+ int ret;
+
+#ifdef CONFIG_STACK_GROWSUP
+ if (write) {
+ ret = expand_stack_downwards(bprm->vma, pos);
+ if (ret < 0)
+ return NULL;
+ }
+#endif
+ ret = get_user_pages(current, bprm->mm, pos,
+ 1, write, 1, &page, NULL);
+ if (ret <= 0)
+ return NULL;
+
+ if (write) {
+ unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
+ struct rlimit *rlim;
+
+ /*
+ * We've historically supported up to 32 pages (ARG_MAX)
+ * of argument strings even with small stacks
+ */
+ if (size <= ARG_MAX)
+ return page;
+
+ /*
+ * 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 > 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.
+ */
+ vma->vm_end = STACK_TOP_MAX;
+ vma->vm_start = vma->vm_end - PAGE_SIZE;
+ vma->vm_flags = VM_STACK_FLAGS;
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+ err = insert_vm_struct(mm, vma);
+ if (err)
+ goto err;
+
+ mm->stack_vm = mm->total_vm = 1;
+ 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 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().
+ */
+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 = init_new_context(current, mm);
+ if (err)
+ goto err;
+
+ err = __bprm_mm_init(bprm);
+ if (err)
+ goto err;
+
+ return 0;
+
+err:
+ if (mm) {
+ bprm->mm = NULL;
+ mmdrop(mm);
+ }
+
+ return err;
+}
+
/*
* count() counts the number of strings in array ARGV.
*/
if (!p)
break;
argv++;
- if(++i > max)
+ if (i++ >= max)
return -E2BIG;
cond_resched();
}
}
/*
- * 'copy_strings()' copies argument/environment strings from user
- * memory to free pages in kernel mem. These are in a format ready
- * to be put directly into the top of new user memory.
+ * '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, char __user * __user * argv,
struct linux_binprm *bprm)
{
struct page *kmapped_page = NULL;
char *kaddr = NULL;
+ unsigned long kpos = 0;
int ret;
while (argc-- > 0) {
unsigned long pos;
if (get_user(str, argv+argc) ||
- !(len = strnlen_user(str, bprm->p))) {
+ !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
ret = -EFAULT;
goto out;
}
- if (bprm->p < len) {
+ if (!valid_arg_len(bprm, len)) {
ret = -E2BIG;
goto out;
}
- bprm->p -= len;
- /* XXX: add architecture specific overflow check here. */
+ /* We're going to work our way backwords. */
pos = bprm->p;
+ str += len;
+ bprm->p -= len;
while (len > 0) {
- int i, new, err;
int offset, bytes_to_copy;
- struct page *page;
offset = pos % PAGE_SIZE;
- i = pos/PAGE_SIZE;
- page = bprm->page[i];
- new = 0;
- if (!page) {
- page = alloc_page(GFP_HIGHUSER);
- bprm->page[i] = page;
+ 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 = -ENOMEM;
+ ret = -E2BIG;
goto out;
}
- new = 1;
- }
- if (page != kmapped_page) {
- if (kmapped_page)
+ 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 (new && offset)
- memset(kaddr, 0, offset);
- bytes_to_copy = PAGE_SIZE - offset;
- if (bytes_to_copy > len) {
- bytes_to_copy = len;
- if (new)
- memset(kaddr+offset+len, 0,
- PAGE_SIZE-offset-len);
- }
- err = copy_from_user(kaddr+offset, str, bytes_to_copy);
- if (err) {
+ if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
ret = -EFAULT;
goto out;
}
-
- pos += bytes_to_copy;
- str += bytes_to_copy;
- len -= bytes_to_copy;
}
}
ret = 0;
out:
- if (kmapped_page)
+ if (kmapped_page) {
+ flush_kernel_dcache_page(kmapped_page);
kunmap(kmapped_page);
+ put_arg_page(kmapped_page);
+ }
return ret;
}
set_fs(oldfs);
return r;
}
-
EXPORT_SYMBOL(copy_strings_kernel);
#ifdef CONFIG_MMU
+
/*
- * This routine is used to map in a page into an address space: needed by
- * execve() for the initial stack and environment pages.
+ * 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:
*
- * vma->vm_mm->mmap_sem is held for writing.
+ * 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.
*/
-void install_arg_page(struct vm_area_struct *vma,
- struct page *page, unsigned long address)
+static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
{
struct mm_struct *mm = vma->vm_mm;
- pte_t * pte;
- spinlock_t *ptl;
+ 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;
- if (unlikely(anon_vma_prepare(vma)))
- goto out;
+ BUG_ON(new_start > new_end);
- flush_dcache_page(page);
- pte = get_locked_pte(mm, address, &ptl);
- if (!pte)
- goto out;
- if (!pte_none(*pte)) {
- pte_unmap_unlock(pte, ptl);
- goto out;
+ /*
+ * 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)
+ */
+ vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
+
+ /*
+ * 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))
+ return -ENOMEM;
+
+ lru_add_drain();
+ tlb = tlb_gather_mmu(mm, 0);
+ 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 : 0);
+ } 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 : 0);
}
- inc_mm_counter(mm, anon_rss);
- lru_cache_add_active(page);
- set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
- page, vma->vm_page_prot))));
- page_add_new_anon_rmap(page, vma, address);
- pte_unmap_unlock(pte, ptl);
-
- /* no need for flush_tlb */
- return;
-out:
- __free_page(page);
- force_sig(SIGKILL, current);
+ tlb_finish_mmu(tlb, new_end, old_end);
+
+ /*
+ * shrink the vma to just the new range.
+ */
+ vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
+
+ return 0;
}
#define EXTRA_STACK_VM_PAGES 20 /* random */
+/*
+ * 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 stack_base;
- struct vm_area_struct *mpnt;
+ unsigned long ret;
+ unsigned long stack_shift;
struct mm_struct *mm = current->mm;
- int i, ret;
- long arg_size;
+ struct vm_area_struct *vma = bprm->vma;
+ struct vm_area_struct *prev = NULL;
+ unsigned long vm_flags;
+ unsigned long stack_base;
#ifdef CONFIG_STACK_GROWSUP
- /* Move the argument and environment strings to the bottom of the
- * stack space.
- */
- int offset, j;
- char *to, *from;
-
- /* Start by shifting all the pages down */
- i = 0;
- for (j = 0; j < MAX_ARG_PAGES; j++) {
- struct page *page = bprm->page[j];
- if (!page)
- continue;
- bprm->page[i++] = page;
- }
-
- /* Now move them within their pages */
- offset = bprm->p % PAGE_SIZE;
- to = kmap(bprm->page[0]);
- for (j = 1; j < i; j++) {
- memmove(to, to + offset, PAGE_SIZE - offset);
- from = kmap(bprm->page[j]);
- memcpy(to + PAGE_SIZE - offset, from, offset);
- kunmap(bprm->page[j - 1]);
- to = from;
- }
- memmove(to, to + offset, PAGE_SIZE - offset);
- kunmap(bprm->page[j - 1]);
-
/* Limit stack size to 1GB */
stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
if (stack_base > (1 << 30))
stack_base = 1 << 30;
- stack_base = PAGE_ALIGN(stack_top - stack_base);
- /* Adjust bprm->p to point to the end of the strings. */
- bprm->p = stack_base + PAGE_SIZE * i - offset;
+ /* Make sure we didn't let the argument array grow too large. */
+ if (vma->vm_end - vma->vm_start > stack_base)
+ return -ENOMEM;
- mm->arg_start = stack_base;
- arg_size = i << PAGE_SHIFT;
+ stack_base = PAGE_ALIGN(stack_top - stack_base);
- /* zero pages that were copied above */
- while (i < MAX_ARG_PAGES)
- bprm->page[i++] = NULL;
+ stack_shift = vma->vm_start - stack_base;
+ mm->arg_start = bprm->p - stack_shift;
+ bprm->p = vma->vm_end - stack_shift;
#else
- stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
- stack_base = PAGE_ALIGN(stack_base);
- bprm->p += stack_base;
+ stack_top = arch_align_stack(stack_top);
+ stack_top = PAGE_ALIGN(stack_top);
+ stack_shift = vma->vm_end - stack_top;
+
+ bprm->p -= stack_shift;
mm->arg_start = bprm->p;
- arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
#endif
- arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
-
if (bprm->loader)
- bprm->loader += stack_base;
- bprm->exec += stack_base;
-
- mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!mpnt)
- return -ENOMEM;
+ bprm->loader -= stack_shift;
+ bprm->exec -= stack_shift;
down_write(&mm->mmap_sem);
- {
- mpnt->vm_mm = mm;
-#ifdef CONFIG_STACK_GROWSUP
- mpnt->vm_start = stack_base;
- mpnt->vm_end = stack_base + arg_size;
-#else
- mpnt->vm_end = stack_top;
- mpnt->vm_start = mpnt->vm_end - arg_size;
-#endif
- /* 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))
- mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
- else if (executable_stack == EXSTACK_DISABLE_X)
- mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
- else
- mpnt->vm_flags = VM_STACK_FLAGS;
- mpnt->vm_flags |= mm->def_flags;
- mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
- if ((ret = insert_vm_struct(mm, mpnt))) {
+ 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;
+
+ 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) {
up_write(&mm->mmap_sem);
- kmem_cache_free(vm_area_cachep, mpnt);
return ret;
}
- mm->stack_vm = mm->total_vm = vma_pages(mpnt);
}
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page *page = bprm->page[i];
- if (page) {
- bprm->page[i] = NULL;
- install_arg_page(mpnt, page, stack_base);
- }
- stack_base += PAGE_SIZE;
- }
+#ifdef CONFIG_STACK_GROWSUP
+ stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+#else
+ stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+#endif
+ ret = expand_stack(vma, stack_base);
+ if (ret)
+ ret = -EFAULT;
+
+out_unlock:
up_write(&mm->mmap_sem);
-
return 0;
}
-
EXPORT_SYMBOL(setup_arg_pages);
-#define free_arg_pages(bprm) do { } while (0)
-
-#else
-
-static inline void free_arg_pages(struct linux_binprm *bprm)
-{
- int i;
-
- for (i = 0; i < MAX_ARG_PAGES; i++) {
- if (bprm->page[i])
- __free_page(bprm->page[i]);
- bprm->page[i] = NULL;
- }
-}
-
#endif /* CONFIG_MMU */
struct file *open_exec(const char *name)
{
struct nameidata nd;
- int err;
struct file *file;
+ int err;
- err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
- file = ERR_PTR(err);
-
- if (!err) {
- struct inode *inode = nd.dentry->d_inode;
- file = ERR_PTR(-EACCES);
- if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
- S_ISREG(inode->i_mode)) {
- int err = vfs_permission(&nd, MAY_EXEC);
- file = ERR_PTR(err);
- if (!err) {
- file = nameidata_to_filp(&nd, O_RDONLY);
- if (!IS_ERR(file)) {
- err = deny_write_access(file);
- if (err) {
- fput(file);
- file = ERR_PTR(err);
- }
- }
-out:
- return file;
- }
- }
- release_open_intent(&nd);
- path_release(&nd);
+ err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
+ FMODE_READ|FMODE_EXEC);
+ if (err)
+ goto out;
+
+ err = -EACCES;
+ if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
+ goto out_path_put;
+
+ if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
+ goto out_path_put;
+
+ err = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_OPEN);
+ if (err)
+ goto out_path_put;
+
+ file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
+ if (IS_ERR(file))
+ return file;
+
+ fsnotify_open(file->f_path.dentry);
+
+ err = deny_write_access(file);
+ if (err) {
+ fput(file);
+ goto out;
}
- goto out;
-}
+ return file;
+
+ out_path_put:
+ release_open_intent(&nd);
+ path_put(&nd.path);
+ out:
+ return ERR_PTR(err);
+}
EXPORT_SYMBOL(open_exec);
int kernel_read(struct file *file, unsigned long offset,
* 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_waiters and changing tsk->mm. The
- * core-inducing thread will increment core_waiters for
- * each thread whose ->mm == old_mm.
+ * checking core_state and changing tsk->mm.
*/
down_read(&old_mm->mmap_sem);
- if (unlikely(old_mm->core_waiters)) {
+ if (unlikely(old_mm->core_state)) {
up_read(&old_mm->mmap_sem);
return -EINTR;
}
if (old_mm) {
up_read(&old_mm->mmap_sem);
BUG_ON(active_mm != old_mm);
+ mm_update_next_owner(old_mm);
mmput(old_mm);
return 0;
}
static int de_thread(struct task_struct *tsk)
{
struct signal_struct *sig = tsk->signal;
- struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
+ struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
- struct task_struct *leader = NULL;
int count;
- /*
- * Tell all the sighand listeners that this sighand has
- * been detached. The signalfd_detach() function grabs the
- * sighand lock, if signal listeners are present on the sighand.
- */
- signalfd_detach(tsk);
-
- /*
- * If we don't share sighandlers, then we aren't sharing anything
- * and we can just re-use it all.
- */
- if (atomic_read(&oldsighand->count) <= 1) {
- BUG_ON(atomic_read(&sig->count) != 1);
- exit_itimers(sig);
- return 0;
- }
-
- newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
- if (!newsighand)
- return -ENOMEM;
-
if (thread_group_empty(tsk))
goto no_thread_group;
/*
* Kill all other threads in the thread group.
- * We must hold tasklist_lock to call zap_other_threads.
*/
- read_lock(&tasklist_lock);
spin_lock_irq(lock);
- if (sig->flags & SIGNAL_GROUP_EXIT) {
+ if (signal_group_exit(sig)) {
/*
* Another group action in progress, just
* return so that the signal is processed.
*/
spin_unlock_irq(lock);
- read_unlock(&tasklist_lock);
- kmem_cache_free(sighand_cachep, newsighand);
return -EAGAIN;
}
-
- /*
- * child_reaper ignores SIGKILL, change it now.
- * Reparenting needs write_lock on tasklist_lock,
- * so it is safe to do it under read_lock.
- */
- if (unlikely(tsk->group_leader == child_reaper(tsk)))
- tsk->nsproxy->pid_ns->child_reaper = tsk;
-
+ sig->group_exit_task = tsk;
zap_other_threads(tsk);
- read_unlock(&tasklist_lock);
- /*
- * Account for the thread group leader hanging around:
- */
- count = 1;
- if (!thread_group_leader(tsk)) {
- count = 2;
- /*
- * The SIGALRM timer survives the exec, but needs to point
- * at us as the new group leader now. We have a race with
- * a timer firing now getting the old leader, so we need to
- * synchronize with any firing (by calling del_timer_sync)
- * before we can safely let the old group leader die.
- */
- sig->tsk = tsk;
- spin_unlock_irq(lock);
- if (hrtimer_cancel(&sig->real_timer))
- hrtimer_restart(&sig->real_timer);
- spin_lock_irq(lock);
- }
+ /* Account for the thread group leader hanging around: */
+ count = thread_group_leader(tsk) ? 1 : 2;
+ sig->notify_count = count;
while (atomic_read(&sig->count) > count) {
- sig->group_exit_task = tsk;
- sig->notify_count = count;
__set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(lock);
schedule();
spin_lock_irq(lock);
}
- sig->group_exit_task = NULL;
- sig->notify_count = 0;
spin_unlock_irq(lock);
/*
* and to assume its PID:
*/
if (!thread_group_leader(tsk)) {
- /*
- * Wait for the thread group leader to be a zombie.
- * It should already be zombie at this point, most
- * of the time.
- */
- leader = tsk->group_leader;
- while (leader->exit_state != EXIT_ZOMBIE)
- yield();
+ struct task_struct *leader = tsk->group_leader;
+
+ sig->notify_count = -1; /* for exit_notify() */
+ for (;;) {
+ write_lock_irq(&tasklist_lock);
+ if (likely(leader->exit_state))
+ break;
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ write_unlock_irq(&tasklist_lock);
+ schedule();
+ }
/*
* The only record we have of the real-time age of a
*/
tsk->start_time = leader->start_time;
- write_lock_irq(&tasklist_lock);
-
- BUG_ON(leader->tgid != tsk->tgid);
- BUG_ON(tsk->pid == tsk->tgid);
+ 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
*/
detach_pid(tsk, PIDTYPE_PID);
tsk->pid = leader->pid;
- attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid));
+ attach_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);
BUG_ON(leader->exit_state != EXIT_ZOMBIE);
leader->exit_state = EXIT_DEAD;
-
write_unlock_irq(&tasklist_lock);
- }
- /*
- * There may be one thread left which is just exiting,
- * but it's safe to stop telling the group to kill themselves.
- */
- sig->flags = 0;
+ release_task(leader);
+ }
+
+ sig->group_exit_task = NULL;
+ sig->notify_count = 0;
no_thread_group:
exit_itimers(sig);
- if (leader)
- release_task(leader);
+ flush_itimer_signals();
- BUG_ON(atomic_read(&sig->count) != 1);
-
- if (atomic_read(&oldsighand->count) == 1) {
- /*
- * Now that we nuked the rest of the thread group,
- * it turns out we are not sharing sighand any more either.
- * So we can just keep it.
- */
- kmem_cache_free(sighand_cachep, newsighand);
- } else {
+ if (atomic_read(&oldsighand->count) != 1) {
+ struct sighand_struct *newsighand;
/*
- * Move our state over to newsighand and switch it in.
+ * 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);
- spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
-
rcu_assign_pointer(tsk->sighand, newsighand);
- recalc_sigpending();
-
- spin_unlock(&newsighand->siglock);
spin_unlock(&oldsighand->siglock);
write_unlock_irq(&tasklist_lock);
BUG_ON(!thread_group_leader(tsk));
return 0;
}
-
+
/*
* These functions flushes out all traces of the currently running executable
* so that a new one can be started
*/
-
static void flush_old_files(struct files_struct * files)
{
long j = -1;
spin_unlock(&files->file_lock);
}
-void get_task_comm(char *buf, struct task_struct *tsk)
+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;
}
void set_task_comm(struct task_struct *tsk, char *buf)
{
char * name;
int i, ch, retval;
- struct files_struct *files;
char tcomm[sizeof(current->comm)];
/*
if (retval)
goto out;
- /*
- * Make sure we have private file handles. Ask the
- * fork helper to do the work for us and the exit
- * helper to do the cleanup of the old one.
- */
- files = current->files; /* refcounted so safe to hold */
- retval = unshare_files();
- if (retval)
- goto out;
+ set_mm_exe_file(bprm->mm, bprm->file);
+
/*
* Release all of the old mmap stuff
*/
retval = exec_mmap(bprm->mm);
if (retval)
- goto mmap_failed;
+ goto out;
bprm->mm = NULL; /* We're using it now */
/* This is the point of no return */
- put_files_struct(files);
-
current->sas_ss_sp = current->sas_ss_size = 0;
- if (current->euid == current->uid && current->egid == current->gid)
- current->mm->dumpable = 1;
+ if (current_euid() == current_uid() && current_egid() == current_gid())
+ set_dumpable(current->mm, 1);
else
- current->mm->dumpable = suid_dumpable;
+ set_dumpable(current->mm, suid_dumpable);
name = bprm->filename;
*/
current->mm->task_size = TASK_SIZE;
- if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
- file_permission(bprm->file, MAY_READ) ||
- (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
- suid_keys(current);
- current->mm->dumpable = suid_dumpable;
+ /* install the new credentials */
+ if (bprm->cred->uid != current_euid() ||
+ bprm->cred->gid != current_egid()) {
+ current->pdeath_signal = 0;
+ } else if (file_permission(bprm->file, MAY_READ) ||
+ bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) {
+ set_dumpable(current->mm, suid_dumpable);
}
+ current->personality &= ~bprm->per_clear;
+
/* An exec changes our domain. We are no longer part of the thread
group */
return 0;
-mmap_failed:
- reset_files_struct(current, files);
out:
return retval;
}
EXPORT_SYMBOL(flush_old_exec);
+/*
+ * 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;
+
+ /* cred_exec_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);
+}
+EXPORT_SYMBOL(install_exec_creds);
+
+/*
+ * determine how safe it is to execute the proposed program
+ * - the caller must hold current->cred_exec_mutex to protect against
+ * PTRACE_ATTACH
+ */
+void check_unsafe_exec(struct linux_binprm *bprm, struct files_struct *files)
+{
+ struct task_struct *p = current, *t;
+ unsigned long flags;
+ unsigned n_fs, n_files, n_sighand;
+
+ bprm->unsafe = tracehook_unsafe_exec(p);
+
+ n_fs = 1;
+ n_files = 1;
+ n_sighand = 1;
+ lock_task_sighand(p, &flags);
+ for (t = next_thread(p); t != p; t = next_thread(t)) {
+ if (t->fs == p->fs)
+ n_fs++;
+ if (t->files == files)
+ n_files++;
+ n_sighand++;
+ }
+
+ if (atomic_read(&p->fs->count) > n_fs ||
+ atomic_read(&p->files->count) > n_files ||
+ atomic_read(&p->sighand->count) > n_sighand)
+ bprm->unsafe |= LSM_UNSAFE_SHARE;
+
+ unlock_task_sighand(p, &flags);
+}
+
/*
* 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 mode;
+ umode_t mode;
struct inode * inode = bprm->file->f_path.dentry->d_inode;
int retval;
if (bprm->file->f_op == NULL)
return -EACCES;
- bprm->e_uid = current->euid;
- bprm->e_gid = current->egid;
+ /* 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)) {
+ if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
/* Set-uid? */
if (mode & S_ISUID) {
- current->personality &= ~PER_CLEAR_ON_SETID;
- bprm->e_uid = inode->i_uid;
+ bprm->per_clear |= PER_CLEAR_ON_SETID;
+ bprm->cred->euid = inode->i_uid;
}
/* Set-gid? */
* executable.
*/
if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
- current->personality &= ~PER_CLEAR_ON_SETID;
- bprm->e_gid = inode->i_gid;
+ bprm->per_clear |= PER_CLEAR_ON_SETID;
+ bprm->cred->egid = inode->i_gid;
}
}
/* fill in binprm security blob */
- retval = security_bprm_set(bprm);
+ 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);
+ memset(bprm->buf, 0, BINPRM_BUF_SIZE);
+ return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
}
EXPORT_SYMBOL(prepare_binprm);
-static int unsafe_exec(struct task_struct *p)
-{
- int unsafe = 0;
- if (p->ptrace & PT_PTRACED) {
- if (p->ptrace & PT_PTRACE_CAP)
- unsafe |= LSM_UNSAFE_PTRACE_CAP;
- else
- unsafe |= LSM_UNSAFE_PTRACE;
- }
- if (atomic_read(&p->fs->count) > 1 ||
- atomic_read(&p->files->count) > 1 ||
- atomic_read(&p->sighand->count) > 1)
- unsafe |= LSM_UNSAFE_SHARE;
-
- return unsafe;
-}
-
-void compute_creds(struct linux_binprm *bprm)
-{
- int unsafe;
-
- if (bprm->e_uid != current->uid)
- suid_keys(current);
- exec_keys(current);
-
- task_lock(current);
- unsafe = unsafe_exec(current);
- security_bprm_apply_creds(bprm, unsafe);
- task_unlock(current);
- security_bprm_post_apply_creds(bprm);
-}
-EXPORT_SYMBOL(compute_creds);
-
/*
* 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.
*/
-void remove_arg_zero(struct linux_binprm *bprm)
+int remove_arg_zero(struct linux_binprm *bprm)
{
- if (bprm->argc) {
- char ch;
-
- do {
- unsigned long offset;
- unsigned long index;
- char *kaddr;
- struct page *page;
+ int ret = 0;
+ unsigned long offset;
+ char *kaddr;
+ struct page *page;
- offset = bprm->p & ~PAGE_MASK;
- index = bprm->p >> PAGE_SHIFT;
+ if (!bprm->argc)
+ return 0;
- page = bprm->page[index];
- kaddr = kmap_atomic(page, KM_USER0);
+ do {
+ offset = bprm->p & ~PAGE_MASK;
+ page = get_arg_page(bprm, bprm->p, 0);
+ if (!page) {
+ ret = -EFAULT;
+ goto out;
+ }
+ kaddr = kmap_atomic(page, KM_USER0);
- /* run through page until we reach end or find NUL */
- do {
- ch = *(kaddr + offset);
+ for (; offset < PAGE_SIZE && kaddr[offset];
+ offset++, bprm->p++)
+ ;
- /* discard that character... */
- bprm->p++;
- offset++;
- } while (offset < PAGE_SIZE && ch != '\0');
+ kunmap_atomic(kaddr, KM_USER0);
+ put_arg_page(page);
- kunmap_atomic(kaddr, KM_USER0);
+ if (offset == PAGE_SIZE)
+ free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
+ } while (offset == PAGE_SIZE);
- /* free the old page */
- if (offset == PAGE_SIZE) {
- __free_page(page);
- bprm->page[index] = NULL;
- }
- } while (ch != '\0');
+ bprm->p++;
+ bprm->argc--;
+ ret = 0;
- bprm->argc--;
- }
+out:
+ return ret;
}
EXPORT_SYMBOL(remove_arg_zero);
*/
int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
{
+ unsigned int depth = bprm->recursion_depth;
int try,retval;
struct linux_binfmt *fmt;
-#ifdef __alpha__
- /* handle /sbin/loader.. */
- {
- struct exec * eh = (struct exec *) bprm->buf;
- if (!bprm->loader && eh->fh.f_magic == 0x183 &&
- (eh->fh.f_flags & 0x3000) == 0x3000)
- {
- struct file * file;
- unsigned long loader;
-
- allow_write_access(bprm->file);
- fput(bprm->file);
- bprm->file = NULL;
-
- loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
-
- file = open_exec("/sbin/loader");
- retval = PTR_ERR(file);
- if (IS_ERR(file))
- return retval;
-
- /* Remember if the application is TASO. */
- bprm->sh_bang = eh->ah.entry < 0x100000000UL;
-
- bprm->file = file;
- bprm->loader = loader;
- retval = prepare_binprm(bprm);
- if (retval<0)
- return retval;
- /* should call search_binary_handler recursively here,
- but it does not matter */
- }
- }
-#endif
retval = security_bprm_check(bprm);
if (retval)
return retval;
retval = -ENOENT;
for (try=0; try<2; try++) {
read_lock(&binfmt_lock);
- for (fmt = formats ; fmt ; fmt = fmt->next) {
+ list_for_each_entry(fmt, &formats, lh) {
int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
if (!fn)
continue;
continue;
read_unlock(&binfmt_lock);
retval = fn(bprm, regs);
+ /*
+ * Restore the depth counter to its starting value
+ * in this call, so we don't have to rely on every
+ * load_binary function to restore it on return.
+ */
+ bprm->recursion_depth = depth;
if (retval >= 0) {
+ if (depth == 0)
+ tracehook_report_exec(fmt, bprm, regs);
put_binfmt(fmt);
allow_write_access(bprm->file);
if (bprm->file)
read_unlock(&binfmt_lock);
if (retval != -ENOEXEC || bprm->mm == NULL) {
break;
-#ifdef CONFIG_KMOD
- }else{
+#ifdef CONFIG_MODULES
+ } else {
#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
if (printable(bprm->buf[0]) &&
printable(bprm->buf[1]) &&
EXPORT_SYMBOL(search_binary_handler);
+void free_bprm(struct linux_binprm *bprm)
+{
+ free_arg_pages(bprm);
+ if (bprm->cred)
+ abort_creds(bprm->cred);
+ kfree(bprm);
+}
+
/*
* sys_execve() executes a new program.
*/
{
struct linux_binprm *bprm;
struct file *file;
- unsigned long env_p;
+ struct files_struct *displaced;
int retval;
- int i;
+
+ retval = unshare_files(&displaced);
+ if (retval)
+ goto out_ret;
retval = -ENOMEM;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
if (!bprm)
- goto out_ret;
+ goto out_files;
+
+ retval = mutex_lock_interruptible(¤t->cred_exec_mutex);
+ if (retval < 0)
+ goto out_free;
+
+ retval = -ENOMEM;
+ bprm->cred = prepare_exec_creds();
+ if (!bprm->cred)
+ goto out_unlock;
+ check_unsafe_exec(bprm, displaced);
file = open_exec(filename);
retval = PTR_ERR(file);
if (IS_ERR(file))
- goto out_kfree;
+ goto out_unlock;
sched_exec();
- bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
-
bprm->file = file;
bprm->filename = filename;
bprm->interp = filename;
- bprm->mm = mm_alloc();
- retval = -ENOMEM;
- if (!bprm->mm)
- goto out_file;
- retval = init_new_context(current, bprm->mm);
- if (retval < 0)
- goto out_mm;
+ retval = bprm_mm_init(bprm);
+ if (retval)
+ goto out_file;
- bprm->argc = count(argv, bprm->p / sizeof(void *));
+ bprm->argc = count(argv, MAX_ARG_STRINGS);
if ((retval = bprm->argc) < 0)
- goto out_mm;
+ goto out;
- bprm->envc = count(envp, bprm->p / sizeof(void *));
+ bprm->envc = count(envp, MAX_ARG_STRINGS);
if ((retval = bprm->envc) < 0)
- goto out_mm;
-
- retval = security_bprm_alloc(bprm);
- if (retval)
goto out;
retval = prepare_binprm(bprm);
if (retval < 0)
goto out;
- env_p = bprm->p;
retval = copy_strings(bprm->argc, argv, bprm);
if (retval < 0)
goto out;
- bprm->argv_len = env_p - bprm->p;
+ current->flags &= ~PF_KTHREAD;
retval = search_binary_handler(bprm,regs);
- if (retval >= 0) {
- free_arg_pages(bprm);
+ if (retval < 0)
+ goto out;
- /* execve success */
- security_bprm_free(bprm);
- acct_update_integrals(current);
- kfree(bprm);
- return retval;
- }
+ /* execve succeeded */
+ mutex_unlock(¤t->cred_exec_mutex);
+ acct_update_integrals(current);
+ free_bprm(bprm);
+ if (displaced)
+ put_files_struct(displaced);
+ return retval;
out:
- /* Something went wrong, return the inode and free the argument pages*/
- for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
- struct page * page = bprm->page[i];
- if (page)
- __free_page(page);
- }
-
- if (bprm->security)
- security_bprm_free(bprm);
-
-out_mm:
if (bprm->mm)
- mmdrop(bprm->mm);
+ mmput (bprm->mm);
out_file:
if (bprm->file) {
fput(bprm->file);
}
-out_kfree:
- kfree(bprm);
+out_unlock:
+ mutex_unlock(¤t->cred_exec_mutex);
+out_free:
+ free_bprm(bprm);
+
+out_files:
+ if (displaced)
+ reset_files_struct(displaced);
out_ret:
return retval;
}
* name into corename, which must have space for at least
* CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
*/
-static int format_corename(char *corename, const char *pattern, long signr)
+static int format_corename(char *corename, long signr)
{
- const char *pat_ptr = pattern;
+ const struct cred *cred = current_cred();
+ const char *pat_ptr = core_pattern;
+ int ispipe = (*pat_ptr == '|');
char *out_ptr = corename;
char *const out_end = corename + CORENAME_MAX_SIZE;
int rc;
int pid_in_pattern = 0;
- int ispipe = 0;
-
- if (*pattern == '|')
- ispipe = 1;
/* Repeat as long as we have more pattern to process and more output
space */
case 'p':
pid_in_pattern = 1;
rc = snprintf(out_ptr, out_end - out_ptr,
- "%d", current->tgid);
+ "%d", task_tgid_vnr(current));
if (rc > out_end - out_ptr)
goto out;
out_ptr += rc;
/* uid */
case 'u':
rc = snprintf(out_ptr, out_end - out_ptr,
- "%d", current->uid);
+ "%d", cred->uid);
if (rc > out_end - out_ptr)
goto out;
out_ptr += rc;
/* gid */
case 'g':
rc = snprintf(out_ptr, out_end - out_ptr,
- "%d", current->gid);
+ "%d", cred->gid);
if (rc > out_end - out_ptr)
goto out;
out_ptr += rc;
goto out;
out_ptr += rc;
break;
+ /* core limit size */
+ case 'c':
+ rc = snprintf(out_ptr, out_end - out_ptr,
+ "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
+ if (rc > out_end - out_ptr)
+ goto out;
+ out_ptr += rc;
+ break;
default:
break;
}
* If core_pattern does not include a %p (as is the default)
* and core_uses_pid is set, then .%pid will be appended to
* the filename. Do not do this for piped commands. */
- if (!ispipe && !pid_in_pattern
- && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) {
+ if (!ispipe && !pid_in_pattern && core_uses_pid) {
rc = snprintf(out_ptr, out_end - out_ptr,
- ".%d", current->tgid);
+ ".%d", task_tgid_vnr(current));
if (rc > out_end - out_ptr)
goto out;
out_ptr += rc;
return ispipe;
}
-static void zap_process(struct task_struct *start)
+static int zap_process(struct task_struct *start)
{
struct task_struct *t;
+ int nr = 0;
start->signal->flags = SIGNAL_GROUP_EXIT;
start->signal->group_stop_count = 0;
t = start;
do {
if (t != current && t->mm) {
- t->mm->core_waiters++;
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
+ nr++;
}
- } while ((t = next_thread(t)) != start);
+ } while_each_thread(start, t);
+
+ return nr;
}
static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
- int exit_code)
+ struct core_state *core_state, int exit_code)
{
struct task_struct *g, *p;
unsigned long flags;
- int err = -EAGAIN;
+ int nr = -EAGAIN;
spin_lock_irq(&tsk->sighand->siglock);
- if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
+ if (!signal_group_exit(tsk->signal)) {
+ mm->core_state = core_state;
tsk->signal->group_exit_code = exit_code;
- zap_process(tsk);
- err = 0;
+ nr = zap_process(tsk);
}
spin_unlock_irq(&tsk->sighand->siglock);
- if (err)
- return err;
+ if (unlikely(nr < 0))
+ return nr;
- if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
+ if (atomic_read(&mm->mm_users) == nr + 1)
goto done;
-
+ /*
+ * We should find and kill all tasks which use this mm, and we should
+ * count them correctly into ->nr_threads. We don't take tasklist
+ * lock, but this is safe wrt:
+ *
+ * fork:
+ * None of sub-threads can fork after zap_process(leader). All
+ * processes which were created before this point should be
+ * visible to zap_threads() because copy_process() adds the new
+ * process to the tail of init_task.tasks list, and lock/unlock
+ * of ->siglock provides a memory barrier.
+ *
+ * do_exit:
+ * The caller holds mm->mmap_sem. This means that the task which
+ * uses this mm can't pass exit_mm(), so it can't exit or clear
+ * its ->mm.
+ *
+ * de_thread:
+ * It does list_replace_rcu(&leader->tasks, ¤t->tasks),
+ * we must see either old or new leader, this does not matter.
+ * However, it can change p->sighand, so lock_task_sighand(p)
+ * must be used. Since p->mm != NULL and we hold ->mmap_sem
+ * it can't fail.
+ *
+ * Note also that "g" can be the old leader with ->mm == NULL
+ * and already unhashed and thus removed from ->thread_group.
+ * This is OK, __unhash_process()->list_del_rcu() does not
+ * clear the ->next pointer, we will find the new leader via
+ * next_thread().
+ */
rcu_read_lock();
for_each_process(g) {
if (g == tsk->group_leader)
continue;
-
+ if (g->flags & PF_KTHREAD)
+ continue;
p = g;
do {
if (p->mm) {
- if (p->mm == mm) {
- /*
- * p->sighand can't disappear, but
- * may be changed by de_thread()
- */
+ if (unlikely(p->mm == mm)) {
lock_task_sighand(p, &flags);
- zap_process(p);
+ nr += zap_process(p);
unlock_task_sighand(p, &flags);
}
break;
}
- } while ((p = next_thread(p)) != g);
+ } while_each_thread(g, p);
}
rcu_read_unlock();
done:
- return mm->core_waiters;
+ atomic_set(&core_state->nr_threads, nr);
+ return nr;
}
-static int coredump_wait(int exit_code)
+static int coredump_wait(int exit_code, struct core_state *core_state)
{
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
- struct completion startup_done;
struct completion *vfork_done;
int core_waiters;
- init_completion(&mm->core_done);
- init_completion(&startup_done);
- mm->core_startup_done = &startup_done;
-
- core_waiters = zap_threads(tsk, mm, exit_code);
+ init_completion(&core_state->startup);
+ core_state->dumper.task = tsk;
+ core_state->dumper.next = NULL;
+ core_waiters = zap_threads(tsk, mm, core_state, exit_code);
up_write(&mm->mmap_sem);
if (unlikely(core_waiters < 0))
}
if (core_waiters)
- wait_for_completion(&startup_done);
+ wait_for_completion(&core_state->startup);
fail:
- BUG_ON(mm->core_waiters);
return core_waiters;
}
-int do_coredump(long signr, int exit_code, struct pt_regs * regs)
+static void coredump_finish(struct mm_struct *mm)
+{
+ struct core_thread *curr, *next;
+ struct task_struct *task;
+
+ next = mm->core_state->dumper.next;
+ while ((curr = next) != NULL) {
+ next = curr->next;
+ task = curr->task;
+ /*
+ * see exit_mm(), curr->task must not see
+ * ->task == NULL before we read ->next.
+ */
+ smp_mb();
+ curr->task = NULL;
+ wake_up_process(task);
+ }
+
+ mm->core_state = NULL;
+}
+
+/*
+ * set_dumpable converts traditional three-value dumpable to two flags and
+ * stores them into mm->flags. It modifies lower two bits of mm->flags, but
+ * these bits are not changed atomically. So get_dumpable can observe the
+ * intermediate state. To avoid doing unexpected behavior, get get_dumpable
+ * return either old dumpable or new one by paying attention to the order of
+ * modifying the bits.
+ *
+ * dumpable | mm->flags (binary)
+ * old new | initial interim final
+ * ---------+-----------------------
+ * 0 1 | 00 01 01
+ * 0 2 | 00 10(*) 11
+ * 1 0 | 01 00 00
+ * 1 2 | 01 11 11
+ * 2 0 | 11 10(*) 00
+ * 2 1 | 11 11 01
+ *
+ * (*) get_dumpable regards interim value of 10 as 11.
+ */
+void set_dumpable(struct mm_struct *mm, int value)
+{
+ switch (value) {
+ case 0:
+ clear_bit(MMF_DUMPABLE, &mm->flags);
+ smp_wmb();
+ clear_bit(MMF_DUMP_SECURELY, &mm->flags);
+ break;
+ case 1:
+ set_bit(MMF_DUMPABLE, &mm->flags);
+ smp_wmb();
+ clear_bit(MMF_DUMP_SECURELY, &mm->flags);
+ break;
+ case 2:
+ set_bit(MMF_DUMP_SECURELY, &mm->flags);
+ smp_wmb();
+ set_bit(MMF_DUMPABLE, &mm->flags);
+ break;
+ }
+}
+
+int get_dumpable(struct mm_struct *mm)
+{
+ int ret;
+
+ ret = mm->flags & 0x3;
+ return (ret >= 2) ? 2 : ret;
+}
+
+void do_coredump(long signr, int exit_code, struct pt_regs *regs)
{
+ struct core_state core_state;
char corename[CORENAME_MAX_SIZE + 1];
struct mm_struct *mm = current->mm;
struct linux_binfmt * binfmt;
struct inode * inode;
struct file * file;
+ const struct cred *old_cred;
+ struct cred *cred;
int retval = 0;
- int fsuid = current->fsuid;
int flag = 0;
int ispipe = 0;
+ unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
+ char **helper_argv = NULL;
+ int helper_argc = 0;
+ char *delimit;
audit_core_dumps(signr);
binfmt = current->binfmt;
if (!binfmt || !binfmt->core_dump)
goto fail;
+
+ cred = prepare_creds();
+ if (!cred) {
+ retval = -ENOMEM;
+ goto fail;
+ }
+
down_write(&mm->mmap_sem);
- if (!mm->dumpable) {
+ /*
+ * If another thread got here first, or we are not dumpable, bail out.
+ */
+ if (mm->core_state || !get_dumpable(mm)) {
up_write(&mm->mmap_sem);
+ put_cred(cred);
goto fail;
}
* process nor do we know its entire history. We only know it
* was tainted so we dump it as root in mode 2.
*/
- if (mm->dumpable == 2) { /* Setuid core dump mode */
+ if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
flag = O_EXCL; /* Stop rewrite attacks */
- current->fsuid = 0; /* Dump root private */
+ cred->fsuid = 0; /* Dump root private */
}
- mm->dumpable = 0;
- retval = coredump_wait(exit_code);
- if (retval < 0)
+ retval = coredump_wait(exit_code, &core_state);
+ if (retval < 0) {
+ put_cred(cred);
goto fail;
+ }
+
+ old_cred = override_creds(cred);
/*
* Clear any false indication of pending signals that might
*/
clear_thread_flag(TIF_SIGPENDING);
- if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
- goto fail_unlock;
-
/*
* lock_kernel() because format_corename() is controlled by sysctl, which
* uses lock_kernel()
*/
lock_kernel();
- ispipe = format_corename(corename, core_pattern, signr);
+ ispipe = format_corename(corename, signr);
unlock_kernel();
+ /*
+ * Don't bother to check the RLIMIT_CORE value if core_pattern points
+ * to a pipe. Since we're not writing directly to the filesystem
+ * RLIMIT_CORE doesn't really apply, as no actual core file will be
+ * created unless the pipe reader choses to write out the core file
+ * at which point file size limits and permissions will be imposed
+ * as it does with any other process
+ */
+ if ((!ispipe) && (core_limit < binfmt->min_coredump))
+ goto fail_unlock;
+
if (ispipe) {
+ helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
+ if (!helper_argv) {
+ printk(KERN_WARNING "%s failed to allocate memory\n",
+ __func__);
+ goto fail_unlock;
+ }
+ /* Terminate the string before the first option */
+ delimit = strchr(corename, ' ');
+ if (delimit)
+ *delimit = '\0';
+ delimit = strrchr(helper_argv[0], '/');
+ if (delimit)
+ delimit++;
+ else
+ delimit = helper_argv[0];
+ if (!strcmp(delimit, current->comm)) {
+ printk(KERN_NOTICE "Recursive core dump detected, "
+ "aborting\n");
+ goto fail_unlock;
+ }
+
+ core_limit = RLIM_INFINITY;
+
/* SIGPIPE can happen, but it's just never processed */
- if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
+ if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
+ &file)) {
printk(KERN_INFO "Core dump to %s pipe failed\n",
corename);
goto fail_unlock;
but keep the previous behaviour for now. */
if (!ispipe && !S_ISREG(inode->i_mode))
goto close_fail;
+ /*
+ * Dont allow local users get cute and trick others to coredump
+ * into their pre-created files:
+ */
+ if (inode->i_uid != current_fsuid())
+ goto close_fail;
if (!file->f_op)
goto close_fail;
if (!file->f_op->write)
if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
goto close_fail;
- retval = binfmt->core_dump(signr, regs, file);
+ retval = binfmt->core_dump(signr, regs, file, core_limit);
if (retval)
current->signal->group_exit_code |= 0x80;
close_fail:
filp_close(file, NULL);
fail_unlock:
- current->fsuid = fsuid;
- complete_all(&mm->core_done);
+ if (helper_argv)
+ argv_free(helper_argv);
+
+ revert_creds(old_cred);
+ put_cred(cred);
+ coredump_finish(mm);
fail:
- return retval;
+ return;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff