#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/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/tracehook.h>
+#include <linux/kmod.h>
+#include <linux/fsnotify.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
-
-#ifdef CONFIG_KMOD
-#include <linux/kmod.h>
-#endif
+#include "internal.h"
int core_uses_pid;
char core_pattern[CORENAME_MAX_SIZE] = "core";
*
* 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 = -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;
return error;
exit:
release_open_intent(&nd);
- path_release(&nd);
+ path_put(&nd.path);
goto out;
}
return NULL;
if (write) {
- struct rlimit *rlim = current->signal->rlim;
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.
* - 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;
static int __bprm_mm_init(struct linux_binprm *bprm)
{
- int err = -ENOMEM;
+ 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)
- goto err;
+ return -ENOMEM;
down_write(&mm->mmap_sem);
vma->vm_mm = mm;
*/
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) {
- up_write(&mm->mmap_sem);
+ 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:
- if (vma) {
- bprm->vma = NULL;
- kmem_cache_free(vm_area_cachep, vma);
- }
-
+ up_write(&mm->mmap_sem);
+ bprm->vma = NULL;
+ kmem_cache_free(vm_area_cachep, vma);
return err;
}
if (!p)
break;
argv++;
- if(++i > max)
+ if (i++ >= max)
return -E2BIG;
cond_resched();
}
/*
* when the old and new regions overlap clear from new_end.
*/
- free_pgd_range(&tlb, new_end, old_end, new_end,
+ free_pgd_range(tlb, new_end, old_end, new_end,
vma->vm_next ? vma->vm_next->vm_start : 0);
} else {
/*
* 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,
+ free_pgd_range(tlb, old_start, old_end, new_end,
vma->vm_next ? vma->vm_next->vm_start : 0);
}
tlb_finish_mmu(tlb, new_end, old_end);
bprm->exec -= stack_shift;
down_write(&mm->mmap_sem);
- vm_flags = vma->vm_flags;
+ vm_flags = VM_STACK_FLAGS;
/*
* Adjust stack execute permissions; explicitly enable for
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 (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;
}
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
- struct task_struct *leader = NULL;
int count;
if (thread_group_empty(tsk))
/*
* 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 (signal_group_exit(sig)) {
/*
* return so that the signal is processed.
*/
spin_unlock_irq(lock);
- read_unlock(&tasklist_lock);
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 == task_child_reaper(tsk)))
- task_active_pid_ns(tsk)->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 = thread_group_leader(tsk) ? 1 : 2;
* and to assume its PID:
*/
if (!thread_group_leader(tsk)) {
- leader = tsk->group_leader;
+ struct task_struct *leader = tsk->group_leader;
- sig->notify_count = -1;
+ sig->notify_count = -1; /* for exit_notify() */
for (;;) {
write_lock_irq(&tasklist_lock);
if (likely(leader->exit_state))
BUG_ON(leader->exit_state != EXIT_ZOMBIE);
leader->exit_state = EXIT_DEAD;
-
write_unlock_irq(&tasklist_lock);
+
+ release_task(leader);
}
sig->group_exit_task = NULL;
no_thread_group:
exit_itimers(sig);
- if (leader)
- release_task(leader);
+ flush_itimer_signals();
if (atomic_read(&oldsighand->count) != 1) {
struct sighand_struct *newsighand;
{
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)
+ if (current_euid() == current_uid() && current_egid() == current_gid())
set_dumpable(current->mm, 1);
else
set_dumpable(current->mm, suid_dumpable);
*/
current->mm->task_size = TASK_SIZE;
- if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
- suid_keys(current);
- set_dumpable(current->mm, 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)) {
- suid_keys(current);
+ 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);
- current->pdeath_signal = 0;
- }
- 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
*/
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;
-#if defined(__alpha__) && defined(CONFIG_ARCH_SUPPORTS_AOUT)
- /* 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 = bprm->vma->vm_end - 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;
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;
+ 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->argc = count(argv, MAX_ARG_STRINGS);
if ((retval = bprm->argc) < 0)
- goto out_mm;
+ goto out;
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) {
- /* execve success */
- free_arg_pages(bprm);
- security_bprm_free(bprm);
- acct_update_integrals(current);
- kfree(bprm);
- return retval;
- }
+ if (retval < 0)
+ goto out;
-out:
- free_arg_pages(bprm);
- if (bprm->security)
- security_bprm_free(bprm);
+ /* execve succeeded */
+ mutex_unlock(¤t->cred_exec_mutex);
+ acct_update_integrals(current);
+ free_bprm(bprm);
+ if (displaced)
+ put_files_struct(displaced);
+ return retval;
-out_mm:
+out:
if (bprm->mm)
mmput (bprm->mm);
allow_write_access(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 */
/* 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;
* 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", task_tgid_vnr(current));
if (rc > out_end - out_ptr)
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 (!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;
}
+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
return (ret >= 2) ? 2 : ret;
}
-int do_coredump(long signr, int exit_code, struct pt_regs * regs)
+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;
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 another thread got here first, or we are not dumpable, bail out.
*/
- if (mm->core_waiters || !get_dumpable(mm)) {
+ if (mm->core_state || !get_dumpable(mm)) {
up_write(&mm->mmap_sem);
+ put_cred(cred);
goto fail;
}
*/
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 */
}
- 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
* 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
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)
* Dont allow local users get cute and trick others to coredump
* into their pre-created files:
*/
- if (inode->i_uid != current->fsuid)
+ if (inode->i_uid != current_fsuid())
goto close_fail;
if (!file->f_op)
goto close_fail;
if (helper_argv)
argv_free(helper_argv);
- current->fsuid = fsuid;
- complete_all(&mm->core_done);
+ revert_creds(old_cred);
+ put_cred(cred);
+ coredump_finish(mm);
fail:
- return retval;
+ return;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff