CRED: Wrap task credential accesses in the filesystem subsystem
[safe/jmp/linux-2.6] / fs / exec.c
index bff43ae..604834f 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -32,6 +32,7 @@
 #include <linux/swap.h>
 #include <linux/string.h>
 #include <linux/init.h>
+#include <linux/pagemap.h>
 #include <linux/highmem.h>
 #include <linux/spinlock.h>
 #include <linux/key.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/tsacct_kern.h>
 #include <linux/cn_proc.h>
 #include <linux/audit.h>
+#include <linux/tracehook.h>
+#include <linux/kmod.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
 
-#ifdef CONFIG_KMOD
-#include <linux/kmod.h>
-#endif
-
 #ifdef __alpha__
 /* for /sbin/loader handling in search_binary_handler() */
 #include <linux/a.out.h>
@@ -106,11 +104,17 @@ static inline void put_binfmt(struct linux_binfmt * fmt)
  */
 asmlinkage long sys_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;
 
@@ -118,7 +122,11 @@ asmlinkage long sys_uselib(const char __user * library)
        if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
                goto exit;
 
-       error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
+       error = -EACCES;
+       if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
+               goto exit;
+
+       error = vfs_permission(&nd, MAY_READ | MAY_EXEC | MAY_OPEN);
        if (error)
                goto exit;
 
@@ -380,7 +388,7 @@ static int count(char __user * __user * argv, int max)
                        if (!p)
                                break;
                        argv++;
-                       if(++i > max)
+                       if (i++ >= max)
                                return -E2BIG;
                        cond_resched();
                }
@@ -656,38 +664,43 @@ EXPORT_SYMBOL(setup_arg_pages);
 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.path.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|O_LARGEFILE);
-                               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_put(&nd.path);
+       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 = vfs_permission(&nd, 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;
+
+       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,
@@ -736,11 +749,11 @@ static int exec_mmap(struct mm_struct *mm)
        tsk->active_mm = mm;
        activate_mm(active_mm, mm);
        task_unlock(tsk);
-       mm_update_next_owner(old_mm);
        arch_pick_mmap_layout(mm);
        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;
        }
@@ -809,8 +822,6 @@ static int de_thread(struct task_struct *tsk)
                        schedule();
                }
 
-               if (unlikely(task_child_reaper(tsk) == leader))
-                       task_active_pid_ns(tsk)->child_reaper = tsk;
                /*
                 * The only record we have of the real-time age of a
                 * process, regardless of execs it's done, is start_time.
@@ -969,7 +980,7 @@ int flush_old_exec(struct linux_binprm * bprm)
        /* This is the point of no return */
        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);
@@ -996,7 +1007,7 @@ int flush_old_exec(struct linux_binprm * bprm)
         */
        current->mm->task_size = TASK_SIZE;
 
-       if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
+       if (bprm->e_uid != current_euid() || bprm->e_gid != current_egid()) {
                suid_keys(current);
                set_dumpable(current->mm, suid_dumpable);
                current->pdeath_signal = 0;
@@ -1036,8 +1047,8 @@ int prepare_binprm(struct linux_binprm *bprm)
        if (bprm->file->f_op == NULL)
                return -EACCES;
 
-       bprm->e_uid = current->euid;
-       bprm->e_gid = current->egid;
+       bprm->e_uid = current_euid();
+       bprm->e_gid = current_egid();
 
        if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
                /* Set-uid? */
@@ -1071,13 +1082,8 @@ 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;
-       }
+       int unsafe = tracehook_unsafe_exec(p);
+
        if (atomic_read(&p->fs->count) > 1 ||
            atomic_read(&p->files->count) > 1 ||
            atomic_read(&p->sighand->count) > 1)
@@ -1090,7 +1096,7 @@ void compute_creds(struct linux_binprm *bprm)
 {
        int unsafe;
 
-       if (bprm->e_uid != current->uid) {
+       if (bprm->e_uid != current_uid()) {
                suid_keys(current);
                current->pdeath_signal = 0;
        }
@@ -1178,7 +1184,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
                        return retval;
 
                /* Remember if the application is TASO.  */
-               bprm->sh_bang = eh->ah.entry < 0x100000000UL;
+               bprm->taso = eh->ah.entry < 0x100000000UL;
 
                bprm->file = file;
                bprm->loader = loader;
@@ -1214,6 +1220,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
                        read_unlock(&binfmt_lock);
                        retval = fn(bprm, regs);
                        if (retval >= 0) {
+                               tracehook_report_exec(fmt, bprm, regs);
                                put_binfmt(fmt);
                                allow_write_access(bprm->file);
                                if (bprm->file)
@@ -1235,8 +1242,8 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
                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]) &&
@@ -1379,17 +1386,14 @@ EXPORT_SYMBOL(set_binfmt);
  * 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 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 */
@@ -1420,7 +1424,7 @@ static int format_corename(char *corename, const char *pattern, long signr)
                        /* uid */
                        case 'u':
                                rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%d", current->uid);
+                                             "%d", current_uid());
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
@@ -1428,7 +1432,7 @@ static int format_corename(char *corename, const char *pattern, long signr)
                        /* gid */
                        case 'g':
                                rc = snprintf(out_ptr, out_end - out_ptr,
-                                             "%d", current->gid);
+                                             "%d", current_gid());
                                if (rc > out_end - out_ptr)
                                        goto out;
                                out_ptr += rc;
@@ -1489,8 +1493,7 @@ static int format_corename(char *corename, const char *pattern, long signr)
         * 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(&current->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)
@@ -1706,7 +1709,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
        struct inode * inode;
        struct file * file;
        int retval = 0;
-       int fsuid = current->fsuid;
+       int fsuid = current_fsuid();
        int flag = 0;
        int ispipe = 0;
        unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
@@ -1753,7 +1756,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
         * 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
@@ -1812,7 +1815,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
         * 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;