linux-stable.git/kernel, branch v4.19.86

bpf: btf: Fix a missing check bug

2019-11-24T07:20:53+00:00

[ Upstream commit 8af03d1ae2e154a8be3631e8694b87007e1bdbc2 ]

In btf_parse_hdr(), the length of the btf data header is firstly copied
from the user space to 'hdr_len' and checked to see whether it is larger
than 'btf_data_size'. If yes, an error code EINVAL is returned. Otherwise,
the whole header is copied again from the user space to 'btf->hdr'.
However, after the second copy, there is no check between
'btf->hdr->hdr_len' and 'hdr_len' to confirm that the two copies get the
same value. Given that the btf data is in the user space, a malicious user
can race to change the data between the two copies. By doing so, the user
can provide malicious data to the kernel and cause undefined behavior.

This patch adds a necessary check after the second copy, to make sure
'btf->hdr->hdr_len' has the same value as 'hdr_len'. Otherwise, an error
code EINVAL will be returned.

Signed-off-by: Wenwen Wang 
Acked-by: Song Liu 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

printk: Give error on attempt to set log buffer length to over 2G

2019-11-24T07:20:46+00:00

[ Upstream commit e6fe3e5b7d16e8f146a4ae7fe481bc6e97acde1e ]

The current printk() is ready to handle log buffer size up to 2G.
Give an explicit error for users who want to use larger log buffer.

Also fix printk formatting to show the 2G as a positive number.

Link: http://lkml.kernel.org/r/20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Sergey Senozhatsky 
Signed-off-by: He Zhe 
Reviewed-by: Sergey Senozhatsky 
[pmladek: Fixed to the really safe limit 2GB.]
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

kexec: Allocate decrypted control pages for kdump if SME is enabled

2019-11-24T07:20:29+00:00

[ Upstream commit 9cf38d5559e813cccdba8b44c82cc46ba48d0896 ]

When SME is enabled in the first kernel, it needs to allocate decrypted
pages for kdump because when the kdump kernel boots, these pages need to
be accessed decrypted in the initial boot stage, before SME is enabled.

 [ bp: clean up text. ]

Signed-off-by: Lianbo Jiang 
Signed-off-by: Borislav Petkov 
Reviewed-by: Tom Lendacky 
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180930031033.22110-3-lijiang@redhat.com
Signed-off-by: Sasha Levin

printk: Correct wrong casting

2019-11-24T07:20:24+00:00

[ Upstream commit 51a72ab7372d85c96104e58036f1b49ba11e5d2b ]

log_first_seq and console_seq are 64-bit unsigned integers.
Correct a wrong casting that might cut off the output.

Link: http://lkml.kernel.org/r/1538239553-81805-2-git-send-email-zhe.he@windriver.com
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: He Zhe 
[sergey.senozhatsky@gmail.com: More descriptive commit message]
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

cpu/SMT: State SMT is disabled even with nosmt and without "=force"

2019-11-24T07:20:18+00:00

[ Upstream commit d0e7d14455d41163126afecd0fcce935463cc512 ]

When booting with "nosmt=force" a message is issued into dmesg to
confirm that SMT has been force-disabled but such a message is not
issued when only "nosmt" is on the kernel command line.

Fix that.

Signed-off-by: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20181004172227.10094-1-bp@alien8.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

printk: CON_PRINTBUFFER console registration is a bit racy

2019-11-24T07:19:45+00:00

[ Upstream commit 884e370ea88c109a3b982f4eb9ecd82510a3a1fe ]

CON_PRINTBUFFER console registration requires us to do several
preparation steps:
- Rollback console_seq to replay logbuf messages which were already
  seen on other consoles;
- Set exclusive_console flag so console_unlock() will ->write() logbuf
  messages only to the exclusive_console driver.

The way we do it, however, is a bit racy

	logbuf_lock_irqsave(flags);
	console_seq = syslog_seq;
	console_idx = syslog_idx;
	logbuf_unlock_irqrestore(flags);
						<< preemption enabled
						<< irqs enabled
	exclusive_console = newcon;
	console_unlock();

We rollback console_seq under logbuf_lock with IRQs disabled, but
we set exclusive_console with local IRQs enabled and logbuf unlocked.
If the system oops-es or panic-s before we set exclusive_console - and
given that we have IRQs and preemption enabled there is such a
possibility - we will re-play all logbuf messages to every registered
console, which may be a bit annoying and time consuming.

Move exclusive_console assignment to the same IRQs-disabled and
logbuf_lock-protected section where we rollback console_seq.

Link: http://lkml.kernel.org/r/20180928095304.9972-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt 
Cc: Sergey Senozhatsky 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

printk: Do not miss new messages when replaying the log

2019-11-24T07:19:44+00:00

[ Upstream commit f92b070f2dc89a8ff1a0cc8b608e20abef894c7d ]

The variable "exclusive_console" is used to reply all existing messages
on a newly registered console. It is cleared when all messages are out.

The problem is that new messages might appear in the meantime. These
are then visible only on the exclusive console.

The obvious solution is to clear "exclusive_console" after we replay
all messages that were already proceed before we started the reply.

Reported-by: Sergey Senozhatsky 
Link: http://lkml.kernel.org/r/20180913123406.14378-1-pmladek@suse.com
To: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Sergey Senozhatsky 
Cc: linux-kernel@vger.kernel.org
Acked-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

kprobes: Don't call BUG_ON() if there is a kprobe in use on free list

2019-11-20T17:46:30+00:00

[ Upstream commit cbdd96f5586151e48317d90a403941ec23f12660 ]

Instead of calling BUG_ON(), if we find a kprobe in use on free kprobe
list, just remove it from the list and keep it on kprobe hash list
as same as other in-use kprobes.

Signed-off-by: Masami Hiramatsu 
Cc: Anil S Keshavamurthy 
Cc: David S . Miller 
Cc: Linus Torvalds 
Cc: Naveen N . Rao 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/153666126882.21306.10738207224288507996.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

signal: Properly deliver SIGILL from uprobes

2019-11-20T17:46:22+00:00

[ Upstream commit 55a3235fc71bf34303e34a95eeee235b2d2a35dd ]

For userspace to tell the difference between a random signal and an
exception, the exception must include siginfo information.

Using SEND_SIG_FORCED for SIGILL is thus wrong, and it will result
in userspace seeing si_code == SI_USER (like a random signal) instead
of si_code == SI_KERNEL or a more specific si_code as all exceptions
deliver.

Therefore replace force_sig_info(SIGILL, SEND_SIG_FORCE, current)
with force_sig(SIG_ILL, current) which gets this right and is
shorter and easier to type.

Fixes: 014940bad8e4 ("uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails")
Fixes: 0b5256c7f173 ("uprobes: Send SIGILL if handle_trampoline() fails")
Reviewed-by: Thomas Gleixner 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Sasha Levin

signal: Always ignore SIGKILL and SIGSTOP sent to the global init

2019-11-20T17:46:21+00:00

[ Upstream commit 86989c41b5ea08776c450cb759592532314a4ed6 ]

If the first process started (aka /sbin/init) receives a SIGKILL it
will panic the system if it is delivered.  Making the system unusable
and undebugable.  It isn't much better if the first process started
receives SIGSTOP.

So always ignore SIGSTOP and SIGKILL sent to init.

This is done in a separate clause in sig_task_ignored as force_sig_info
can clear SIG_UNKILLABLE and this protection should work even then.

Reviewed-by: Thomas Gleixner 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Sasha Levin