user/sven/linux.git/kernel, branch v3.18.40

module: Invalidate signatures on force-loaded modules

2016-08-22T16:23:18Z

[ Upstream commit bca014caaa6130e57f69b5bf527967aa8ee70fdd ] Signing a module should only make it trusted by the specific kernel it was built for, not anything else. Loading a signed module meant for a kernel with a different ABI could have interesting effects. Therefore, treat all signatures as invalid when a module is force-loaded. Signed-off-by: Ben Hutchings Cc: stable@vger.kernel.org Signed-off-by: Rusty Russell Signed-off-by: Sasha Levin

audit: fix a double fetch in audit_log_single_execve_arg()

2016-08-22T16:23:15Z

[ Upstream commit 43761473c254b45883a64441dd0bc85a42f3645c ] There is a double fetch problem in audit_log_single_execve_arg() where we first check the execve(2) argumnets for any "bad" characters which would require hex encoding and then re-fetch the arguments for logging in the audit record[1]. Of course this leaves a window of opportunity for an unsavory application to munge with the data. This patch reworks things by only fetching the argument data once[2] into a buffer where it is scanned and logged into the audit records(s). In addition to fixing the double fetch, this patch improves on the original code in a few other ways: better handling of large arguments which require encoding, stricter record length checking, and some performance improvements (completely unverified, but we got rid of some strlen() calls, that's got to be a good thing). As part of the development of this patch, I've also created a basic regression test for the audit-testsuite, the test can be tracked on GitHub at the following link: * https://github.com/linux-audit/audit-testsuite/issues/25 [1] If you pay careful attention, there is actually a triple fetch problem due to a strnlen_user() call at the top of the function. [2] This is a tiny white lie, we do make a call to strnlen_user() prior to fetching the argument data. I don't like it, but due to the way the audit record is structured we really have no choice unless we copy the entire argument at once (which would require a rather wasteful allocation). The good news is that with this patch the kernel no longer relies on this strnlen_user() value for anything beyond recording it in the log, we also update it with a trustworthy value whenever possible. Reported-by: Pengfei Wang Cc: Signed-off-by: Paul Moore Signed-off-by: Sasha Levin

Fix broken audit tests for exec arg len

2016-08-22T16:23:15Z

[ Upstream commit 45820c294fe1b1a9df495d57f40585ef2d069a39 ] The "fix" in commit 0b08c5e5944 ("audit: Fix check of return value of strnlen_user()") didn't fix anything, it broke things. As reported by Steven Rostedt: "Yes, strnlen_user() returns 0 on fault, but if you look at what len is set to, than you would notice that on fault len would be -1" because we just subtracted one from the return value. So testing against 0 doesn't test for a fault condition, it tests against a perfectly valid empty string. Also fix up the usual braindamage wrt using WARN_ON() inside a conditional - make it part of the conditional and remove the explicit unlikely() (which is already part of the WARN_ON*() logic, exactly so that you don't have to write unreadable code. Reported-and-tested-by: Steven Rostedt Cc: Jan Kara Cc: Paul Moore Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

audit: Fix check of return value of strnlen_user()

2016-08-22T16:23:14Z

[ Upstream commit 0b08c5e59441d08ab4b5e72afefd5cd98a4d83df ] strnlen_user() returns 0 when it hits fault, not -1. Fix the test in audit_log_single_execve_arg(). Luckily this shouldn't ever happen unless there's a kernel bug so it's mostly a cosmetic fix. CC: Paul Moore Signed-off-by: Jan Kara Signed-off-by: Paul Moore Signed-off-by: Sasha Levin

posix_cpu_timer: Exit early when process has been reaped

2016-08-08T01:47:27Z

[ Upstream commit 2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307 ] Variable "now" seems to be genuinely used unintialized if branch if (CPUCLOCK_PERTHREAD(timer->it_clock)) { is not taken and branch if (unlikely(sighand == NULL)) { is taken. In this case the process has been reaped and the timer is marked as disarmed anyway. So none of the postprocessing of the sample is required. Return right away. Signed-off-by: Alexey Dobriyan Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin

pipe: limit the per-user amount of pages allocated in pipes

2016-07-12T12:48:19Z

[ Upstream commit 759c01142a5d0f364a462346168a56de28a80f52 ] On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds Signed-off-by: Willy Tarreau Signed-off-by: Al Viro Signed-off-by: Sasha Levin

bpf: fix double-fdput in replace_map_fd_with_map_ptr()

2016-07-12T12:48:09Z

[ Upstream commit 8358b02bf67d3a5d8a825070e1aa73f25fb2e4c7 ] When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode references a non-map file descriptor as a map file descriptor, the error handling code called fdput() twice instead of once (in __bpf_map_get() and in replace_map_fd_with_map_ptr()). If the file descriptor table of the current task is shared, this causes f_count to be decremented too much, allowing the struct file to be freed while it is still in use (use-after-free). This can be exploited to gain root privileges by an unprivileged user. This bug was introduced in commit 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only exploitable since commit 1be7f75d1668 ("bpf: enable non-root eBPF programs") because previously, CAP_SYS_ADMIN was required to reach the vulnerable code. (posted publicly according to request by maintainer) Signed-off-by: Jann Horn Signed-off-by: Linus Torvalds Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

futex: Acknowledge a new waiter in counter before plist

2016-07-12T12:47:45Z

[ Upstream commit fe1bce9e2107ba3a8faffe572483b6974201a0e6 ] Otherwise an incoming waker on the dest hash bucket can miss the waiter adding itself to the plist during the lockless check optimization (small window but still the correct way of doing this); similarly to the decrement counterpart. Suggested-by: Peter Zijlstra Signed-off-by: Davidlohr Bueso Cc: Davidlohr Bueso Cc: bigeasy@linutronix.de Cc: dvhart@infradead.org Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1461208164-29150-1-git-send-email-dave@stgolabs.net Signed-off-by: Thomas Gleixner Signed-off-by: Sasha Levin

tracing: Handle NULL formats in hold_module_trace_bprintk_format()

2016-07-12T12:46:57Z

[ Upstream commit 70c8217acd4383e069fe1898bbad36ea4fcdbdcc ] If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com Reported-by: xingzhen Acked-by: Namhyung Kim Fixes: 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin

kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w

2016-07-12T12:46:50Z

[ Upstream commit 57675cb976eff977aefb428e68e4e0236d48a9ff ] Lengthy output of sysrq-w may take a lot of time on slow serial console. Currently we reset NMI-watchdog on the current CPU to avoid spurious lockup messages. Sometimes this doesn't work since softlockup watchdog might trigger on another CPU which is waiting for an IPI to proceed. We reset softlockup watchdogs on all CPUs, but we do this only after listing all tasks, and this may be too late on a busy system. So, reset watchdogs CPUs earlier, in for_each_process_thread() loop. Signed-off-by: Andrey Ryabinin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin