diff options
Diffstat (limited to 'kernel/sys.c')
-rw-r--r-- | kernel/sys.c | 52 |
1 files changed, 32 insertions, 20 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index 667b2e62fad2..a4e372b798a5 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -325,6 +325,7 @@ out_unlock: * SMP: There are not races, the GIDs are checked only by filesystem * operations (as far as semantic preservation is concerned). */ +#ifdef CONFIG_MULTIUSER SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid) { struct user_namespace *ns = current_user_ns(); @@ -815,6 +816,7 @@ change_okay: commit_creds(new); return old_fsgid; } +#endif /* CONFIG_MULTIUSER */ /** * sys_getpid - return the thread group id of the current process @@ -1108,6 +1110,7 @@ DECLARE_RWSEM(uts_sem); /* * Work around broken programs that cannot handle "Linux 3.0". * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 + * And we map 4.x to 2.6.60+x, so 4.0 would be 2.6.60. */ static int override_release(char __user *release, size_t len) { @@ -1127,7 +1130,7 @@ static int override_release(char __user *release, size_t len) break; rest++; } - v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; + v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 60; copy = clamp_t(size_t, len, 1, sizeof(buf)); copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); ret = copy_to_user(release, buf, copy + 1); @@ -1646,14 +1649,13 @@ SYSCALL_DEFINE1(umask, int, mask) return mask; } -static int prctl_set_mm_exe_file_locked(struct mm_struct *mm, unsigned int fd) +static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) { struct fd exe; + struct file *old_exe, *exe_file; struct inode *inode; int err; - VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm); - exe = fdget(fd); if (!exe.file) return -EBADF; @@ -1677,15 +1679,22 @@ static int prctl_set_mm_exe_file_locked(struct mm_struct *mm, unsigned int fd) /* * Forbid mm->exe_file change if old file still mapped. */ + exe_file = get_mm_exe_file(mm); err = -EBUSY; - if (mm->exe_file) { + if (exe_file) { struct vm_area_struct *vma; - for (vma = mm->mmap; vma; vma = vma->vm_next) - if (vma->vm_file && - path_equal(&vma->vm_file->f_path, - &mm->exe_file->f_path)) - goto exit; + down_read(&mm->mmap_sem); + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (!vma->vm_file) + continue; + if (path_equal(&vma->vm_file->f_path, + &exe_file->f_path)) + goto exit_err; + } + + up_read(&mm->mmap_sem); + fput(exe_file); } /* @@ -1699,10 +1708,18 @@ static int prctl_set_mm_exe_file_locked(struct mm_struct *mm, unsigned int fd) goto exit; err = 0; - set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */ + /* set the new file, lockless */ + get_file(exe.file); + old_exe = xchg(&mm->exe_file, exe.file); + if (old_exe) + fput(old_exe); exit: fdput(exe); return err; +exit_err: + up_read(&mm->mmap_sem); + fput(exe_file); + goto exit; } #ifdef CONFIG_CHECKPOINT_RESTORE @@ -1837,10 +1854,9 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL; } - down_write(&mm->mmap_sem); if (prctl_map.exe_fd != (u32)-1) - error = prctl_set_mm_exe_file_locked(mm, prctl_map.exe_fd); - downgrade_write(&mm->mmap_sem); + error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd); + down_read(&mm->mmap_sem); if (error) goto out; @@ -1906,12 +1922,8 @@ static int prctl_set_mm(int opt, unsigned long addr, if (!capable(CAP_SYS_RESOURCE)) return -EPERM; - if (opt == PR_SET_MM_EXE_FILE) { - down_write(&mm->mmap_sem); - error = prctl_set_mm_exe_file_locked(mm, (unsigned int)addr); - up_write(&mm->mmap_sem); - return error; - } + if (opt == PR_SET_MM_EXE_FILE) + return prctl_set_mm_exe_file(mm, (unsigned int)addr); if (addr >= TASK_SIZE || addr < mmap_min_addr) return -EINVAL; |