user/sven/linux.git/Documentation/userspace-api, branch v5.4.262

Documentation: seccomp: Fix user notification documentation

2021-06-03T06:59:03Z

commit aac902925ea646e461c95edc98a8a57eb0def917 upstream. The documentation had some previously incorrect information about how userspace notifications (and responses) were handled due to a change from a previously proposed patchset. Signed-off-by: Sargun Dhillon Acked-by: Tycho Andersen Acked-by: Christian Brauner Signed-off-by: Kees Cook Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210517193908.3113-2-sargun@sargun.me Signed-off-by: Greg Kroah-Hartman

docs: remove extra conf.py files

2019-07-17T09:57:52Z

Now that the latex_documents are handled automatically, we can remove those extra conf.py files. Signed-off-by: Mauro Carvalho Chehab

docs: ocxl.rst: add it to the uAPI book

2019-07-15T14:03:02Z

The content of this file is user-faced. Signed-off-by: Mauro Carvalho Chehab Acked-by: Andrew Donnellan

Documentation: Add section about CPU vulnerabilities for Spectre

2019-06-26T17:42:41Z

Add documentation for Spectre vulnerability and the mitigation mechanisms: - Explain the problem and risks - Document the mitigation mechanisms - Document the command line controls - Document the sysfs files Co-developed-by: Andi Kleen Signed-off-by: Andi Kleen Co-developed-by: Tim Chen Signed-off-by: Tim Chen Reviewed-by: Randy Dunlap Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet

Documentation: seccomp: unify list indentation

2019-03-18T18:00:28Z

Use tabs to indent SECCOMP_RET_USER_NOTIF definition, for consistency with other items in this list. Signed-off-by: Jakub Wilk Acked-by: Kees Cook Signed-off-by: Jonathan Corbet

Documentation: seccomp: fix reST markup

2019-03-18T18:00:17Z

Signed-off-by: Jakub Wilk Acked-by: Kees Cook Signed-off-by: Jonathan Corbet

x86/speculation: Add PR_SPEC_DISABLE_NOEXEC

2019-01-29T21:11:49Z

With the default SPEC_STORE_BYPASS_SECCOMP/SPEC_STORE_BYPASS_PRCTL mode, the TIF_SSBD bit will be inherited when a new task is fork'ed or cloned. It will also remain when a new program is execve'ed. Only certain class of applications (like Java) that can run on behalf of multiple users on a single thread will require disabling speculative store bypass for security purposes. Those applications will call prctl(2) at startup time to disable SSB. They won't rely on the fact the SSB might have been disabled. Other applications that don't need SSBD will just move on without checking if SSBD has been turned on or not. The fact that the TIF_SSBD is inherited across execve(2) boundary will cause performance of applications that don't need SSBD but their predecessors have SSBD on to be unwittingly impacted especially if they write to memory a lot. To remedy this problem, a new PR_SPEC_DISABLE_NOEXEC argument for the PR_SET_SPECULATION_CTRL option of prctl(2) is added to allow applications to specify that the SSBD feature bit on the task structure should be cleared whenever a new program is being execve'ed. Suggested-by: Thomas Gleixner Signed-off-by: Waiman Long Signed-off-by: Thomas Gleixner Cc: Borislav Petkov Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Cc: "H. Peter Anvin" Cc: Andi Kleen Cc: David Woodhouse Cc: Jiri Kosina Cc: Josh Poimboeuf Cc: Tim Chen Cc: KarimAllah Ahmed Cc: Peter Zijlstra Cc: Konrad Rzeszutek Wilk Link: https://lkml.kernel.org/r/1547676096-3281-1-git-send-email-longman@redhat.com

Merge branch 'next-seccomp' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2019-01-02T17:48:13Z

Pull seccomp updates from James Morris: - Add SECCOMP_RET_USER_NOTIF - seccomp fixes for sparse warnings and s390 build (Tycho) * 'next-seccomp' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: seccomp, s390: fix build for syscall type change seccomp: fix poor type promotion samples: add an example of seccomp user trap seccomp: add a return code to trap to userspace seccomp: switch system call argument type to void * seccomp: hoist struct seccomp_data recalculation higher

seccomp: add a return code to trap to userspace

2018-12-12T00:28:41Z

This patch introduces a means for syscalls matched in seccomp to notify some other task that a particular filter has been triggered. The motivation for this is primarily for use with containers. For example, if a container does an init_module(), we obviously don't want to load this untrusted code, which may be compiled for the wrong version of the kernel anyway. Instead, we could parse the module image, figure out which module the container is trying to load and load it on the host. As another example, containers cannot mount() in general since various filesystems assume a trusted image. However, if an orchestrator knows that e.g. a particular block device has not been exposed to a container for writing, it want to allow the container to mount that block device (that is, handle the mount for it). This patch adds functionality that is already possible via at least two other means that I know about, both of which involve ptrace(): first, one could ptrace attach, and then iterate through syscalls via PTRACE_SYSCALL. Unfortunately this is slow, so a faster version would be to install a filter that does SECCOMP_RET_TRACE, which triggers a PTRACE_EVENT_SECCOMP. Since ptrace allows only one tracer, if the container runtime is that tracer, users inside the container (or outside) trying to debug it will not be able to use ptrace, which is annoying. It also means that older distributions based on Upstart cannot boot inside containers using ptrace, since upstart itself uses ptrace to monitor services while starting. The actual implementation of this is fairly small, although getting the synchronization right was/is slightly complex. Finally, it's worth noting that the classic seccomp TOCTOU of reading memory data from the task still applies here, but can be avoided with careful design of the userspace handler: if the userspace handler reads all of the task memory that is necessary before applying its security policy, the tracee's subsequent memory edits will not be read by the tracer. Signed-off-by: Tycho Andersen CC: Kees Cook CC: Andy Lutomirski CC: Oleg Nesterov CC: Eric W. Biederman CC: "Serge E. Hallyn" Acked-by: Serge Hallyn CC: Christian Brauner CC: Tyler Hicks CC: Akihiro Suda Signed-off-by: Kees Cook

x86/speculation: Add prctl() control for indirect branch speculation

2018-11-28T10:57:13Z

Add the PR_SPEC_INDIRECT_BRANCH option for the PR_GET_SPECULATION_CTRL and PR_SET_SPECULATION_CTRL prctls to allow fine grained per task control of indirect branch speculation via STIBP and IBPB. Invocations: Check indirect branch speculation status with - prctl(PR_GET_SPECULATION_CTRL, PR_SPEC_INDIRECT_BRANCH, 0, 0, 0); Enable indirect branch speculation with - prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_INDIRECT_BRANCH, PR_SPEC_ENABLE, 0, 0); Disable indirect branch speculation with - prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_INDIRECT_BRANCH, PR_SPEC_DISABLE, 0, 0); Force disable indirect branch speculation with - prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_INDIRECT_BRANCH, PR_SPEC_FORCE_DISABLE, 0, 0); See Documentation/userspace-api/spec_ctrl.rst. Signed-off-by: Tim Chen Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jiri Kosina Cc: Tom Lendacky Cc: Josh Poimboeuf Cc: Andrea Arcangeli Cc: David Woodhouse Cc: Andi Kleen Cc: Dave Hansen Cc: Casey Schaufler Cc: Asit Mallick Cc: Arjan van de Ven Cc: Jon Masters Cc: Waiman Long Cc: Greg KH Cc: Dave Stewart Cc: Kees Cook Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185005.866780996@linutronix.de