Notices Welcome to LinuxQuestions. The result would be an "oops," which would result in the death of the process that made the system call. Attempting to reference the user-space memory directly could generate a page fault, which is something that kernel code is not allowed to do.
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If you need to reset your password, click here. Even if the pointer does mean the same thing in kernel space, user-space memory is paged, and the memory in question might not be resident in RAM when the system call is made.
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Introduction to Linux - A Hands on Guide This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
Let us repeat that the buff argument to the read and write methods is a user-space pointer. Visit the following links: If you have any problems with the registration process or your account login, please contact us.
The pointer in question has been supplied by a user program, which could be buggy or malicious. Note that registered members see fewer ads, and ContentLink is completely disabled once you log in. There are a few reasons for this restriction: Registration is quick, simple and absolutely free.
Therefore, it cannot be directly dereferenced by kernel code. Are you new to LinuxQuestions. You are currently viewing LQ as a guest. Depending on which architecture your driver is running on, and how the kernel was configured, the user-space pointer may not be valid while running in kernel mode at all.
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They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.Is it possible in linux to give a user read/write access to all files and directories like root?
EDIT I have a special case. I need to create a folder structure on which I can grand a special user. Although there are already a lot of good security features built into Linux-based systems, one very important potential vulnerability can exist when local access is granted - - that is file permission based issues resulting from a user not assigning the correct permissions to files and directories.
Understanding Linux File Permissions.
Depending on the kernel version of the Linux guest operating system, VMware Tools uses different components to provide shared-folder functionality. In Linux kernels prior to versionthe VMware Tools services script loads a driver that performs the mount. Optimizing Read and Write Access to. In a previous article, we showed you how to create a shared directory in billsimas.com, we will describe how to give read/write access to a user on a specific directory in Linux.
There are two possible methods of doing this: the first is using ACLs (Access Control Lists) and the second is creating user groups to manage file permissions, as explained below.
mount NTFS file system with read write access ; support for NTFS file system is more feature of Linux kernel modules rather than Linux distributions. First verify if we have NTFS modules installed on our system.
How to mount partition with ntfs file system and read write access. Feb 02, · write access to a Windows partition folder from Linux (as root) I want to copy a file from Linux to a separate Windows hpfs/ntfs a regular user.
Make sure you have the ntfs-3g and fuse packages installed before proceeding.
Make sure that the .Download