Eric W. Biederman 03eed7afbc mm: Add a user_ns owner to mm_struct and fix ptrace permission checks ... commit bfedb58925 upstream. During exec dumpable is cleared if the file that is being executed is not readable by the user executing the file. A bug in ptrace_may_access allows reading the file if the executable happens to enter into a subordinate user namespace (aka clone(CLONE_NEWUSER), unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER). This problem is fixed with only necessary userspace breakage by adding a user namespace owner to mm_struct, captured at the time of exec, so it is clear in which user namespace CAP_SYS_PTRACE must be present in to be able to safely give read permission to the executable. The function ptrace_may_access is modified to verify that the ptracer has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns. This ensures that if the task changes it's cred into a subordinate user namespace it does not become ptraceable. The function ptrace_attach is modified to only set PT_PTRACE_CAP when CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of PT_PTRACE_CAP is to be a flag to note that whatever permission changes the task might go through the tracer has sufficient permissions for it not to be an issue. task->cred->user_ns is always the same as or descendent of mm->user_ns. Which guarantees that having CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks credentials. To prevent regressions mm->dumpable and mm->user_ns are not considered when a task has no mm. As simply failing ptrace_may_attach causes regressions in privileged applications attempting to read things such as /proc/<pid>/stat Acked-by: Kees Cook <keescook@chromium.org> Tested-by: Cyrill Gorcunov <gorcunov@openvz.org> Fixes: 8409cca705 ("userns: allow ptrace from non-init user namespaces") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-01-06 11:16:11 +01:00
..
acpi	Merge branch 'acpi-pci'	2015-11-07 01:30:10 +01:00
asm-generic	asm-generic: make copy_from_user() zero the destination properly	2016-09-24 10:07:45 +02:00
clocksource
crypto	crypto: ghash-generic - move common definitions to a new header file	2016-10-22 12:26:56 +02:00
drm	drm/prime: Pass the right module owner through to dma_buf_export()	2016-10-31 04:13:57 -06:00
dt-bindings	ARM: DT updates for v4.4	2015-11-10 15:06:26 -08:00
keys
kvm	KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active	2015-11-24 18:07:40 +01:00
linux	mm: Add a user_ns owner to mm_struct and fix ptrace permission checks	2017-01-06 11:16:11 +01:00
math-emu
media	videobuf2-core: Check user space planes array in dqbuf	2016-05-04 14:48:50 -07:00
memory
misc
net	tcp: take care of truncations done by sk_filter()	2016-11-21 10:06:40 +01:00
pcmcia
ras
rdma	IB/security: Restrict use of the write() interface	2016-05-04 14:48:48 -07:00
rxrpc
scsi	scsi: Add intermediate STARGET_REMOVE state to scsi_target_state	2016-06-01 12:15:54 -07:00
soc	ARM: SoC driver updates for v4.4	2015-11-10 15:00:03 -08:00
sound	ALSA: rawmidi: Make snd_rawmidi_transmit() race-free	2016-02-17 12:30:58 -08:00
target	target: Make EXTENDED_COPY 0xe4 failure return COPY TARGET DEVICE NOT REACHABLE	2016-10-28 03:01:36 -04:00
trace	SUNRPC: Don't allocate a full sockaddr_storage for tracing	2016-08-20 18:09:26 +02:00
uapi	can: raw: raw_setsockopt: limit number of can_filter that can be set	2016-12-15 08:49:22 -08:00
video	drm/imx: Match imx-ipuv3-crtc components using device node in platform data	2016-06-07 18:14:37 -07:00
xen	xen: Fix page <-> pfn conversion on 32 bit systems	2016-05-11 11:21:14 +02:00
Kbuild