diff options
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 0938fd3ad228..01fef79ac761 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -539,8 +539,9 @@ static inline bool can_do_pageout(struct vm_area_struct *vma) * otherwise we'd be including shared non-exclusive mappings, which * opens a side channel. */ - return inode_owner_or_capable(file_inode(vma->vm_file)) || - inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0; + return inode_owner_or_capable(&init_user_ns, + file_inode(vma->vm_file)) || + file_permission(vma->vm_file, MAY_WRITE) == 0; } static long madvise_pageout(struct vm_area_struct *vma, @@ -1197,12 +1198,22 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, goto release_task; } - mm = mm_access(task, PTRACE_MODE_ATTACH_FSCREDS); + /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */ + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS); if (IS_ERR_OR_NULL(mm)) { ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH; goto release_task; } + /* + * Require CAP_SYS_NICE for influencing process performance. Note that + * only non-destructive hints are currently supported. + */ + if (!capable(CAP_SYS_NICE)) { + ret = -EPERM; + goto release_mm; + } + total_len = iov_iter_count(&iter); while (iov_iter_count(&iter)) { @@ -1217,6 +1228,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, if (ret == 0) ret = total_len - iov_iter_count(&iter); +release_mm: mmput(mm); release_task: put_task_struct(task); |