- 25 Jun, 2019 31 commits
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Michal Suchanek authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit cb3d6759 upstream. Check what firmware told us and enable/disable the barrier_nospec as appropriate. We err on the side of enabling the barrier, as it's no-op on older systems, see the comment for more detail. Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
Juerg Haefliger <juergh@canonical.com> Signed-off-by:
Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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Michal Suchanek authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 815069ca upstream. Note that unlike RFI which is patched only in kernel the nospec state reflects settings at the time the module was loaded. Iterating all modules and re-patching every time the settings change is not implemented. Based on lwsync patching. Signed-off-by:
Michal Suchanek <msuchanek@suse.de> Signed-off-by:
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Michal Suchanek authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 2eea7f06 upstream. Based on the RFI patching. This is required to be able to disable the speculation barrier. Only one barrier type is supported and it does nothing when the firmware does not enable it. Also re-patching modules is not supported So the only meaningful thing that can be done is patching out the speculation barrier at boot when the user says it is not wanted. Signed-off-by:
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Michal Suchanek authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit a6b3964a upstream. A no-op form of ori (or immediate of 0 into r31 and the result stored in r31) has been re-tasked as a speculation barrier. The instruction only acts as a barrier on newer machines with appropriate firmware support. On older CPUs it remains a harmless no-op. Implement barrier_nospec using this instruction. mpe: The semantics of the instruction are believed to be that it prevents execution of subsequent instructions until preceding branches have been fully resolved and are no longer executing speculatively. There is no further documentation available at this time. Signed-off-by:
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Nicholas Piggin authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit a048a07d upstream. On some CPUs we can prevent a vulnerability related to store-to-load forwarding by preventing store forwarding between privilege domains, by inserting a barrier in kernel entry and exit paths. This is known to be the case on at least Power7, Power8 and Power9 powerpc CPUs. Barriers must be inserted generally before the first load after moving to a higher privilege, and after the last store before moving to a lower privilege, HV and PR privilege transitions must be protected. Barriers are added as patch sections, with all kernel/hypervisor entry points patched, and the exit points to lower privilge levels patched similarly to the RFI flush patching. Firmware advertisement is not implemented yet, so CPU flush types are hard coded. Thanks to Michal Suchánek for bug fixes and review. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by:
Michael Neuling <mikey@neuling.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Juerg Haefliger authored
Revert "UBUNTU: SAUCE: powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit" BugLink: https://bugs.launchpad.net/bugs/1830176 This reverts commit 00dcbda8 to be replaced by the upstream implementation. Signed-off-by:
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Michael Ellerman authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 501a78cb upstream. The recent LPM changes to setup_rfi_flush() are causing some section mismatch warnings because we removed the __init annotation on setup_rfi_flush(): The function setup_rfi_flush() references the function __init ppc64_bolted_size(). the function __init memblock_alloc_base(). The references are actually in init_fallback_flush(), but that is inlined into setup_rfi_flush(). These references are safe because: - only pseries calls setup_rfi_flush() at runtime - pseries always passes L1D_FLUSH_FALLBACK at boot - so the fallback flush area will always be allocated - so the check in init_fallback_flush() will always return early: /* Only allocate the fallback flush area once (at boot time). */ if (l1d_flush_fallback_area) return; - and therefore we won't actually call the freed init routines. We should rework the code to make it safer by default rather than relying on the above, but for now as a quick-fix just add a __ref annotation to squash the warning. Fixes: abf110f3 ("powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again") Signed-off-by:
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Nicholas Piggin authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit bdcb1aef upstream. The fallback RFI flush is used when firmware does not provide a way to flush the cache. It's a "displacement flush" that evicts useful data by displacing it with an uninteresting buffer. The flush has to take care to work with implementation specific cache replacment policies, so the recipe has been in flux. The initial slow but conservative approach is to touch all lines of a congruence class, with dependencies between each load. It has since been determined that a linear pattern of loads without dependencies is sufficient, and is significantly faster. Measuring the speed of a null syscall with RFI fallback flush enabled gives the relative improvement: P8 - 1.83x P9 - 1.75x The flush also becomes simpler and more adaptable to different cache geometries. Signed-off-by:
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Michael Ellerman authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 274920a3 upstream. Signed-off-by:
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Kai-Heng Feng authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit d7a6c0ce upstream. USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working after S3: [ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin [ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110) After some experiments, I found that disabling LPM can workaround the issue. On some platforms, the USB power is cut during S3, so the driver uses reset-resume to resume the device. During port resume, LPM gets enabled twice, by usb_reset_and_verify_device() and usb_port_resume(). Consolidate all checks into new LPM helpers to make sure LPM only gets enabled once. Fixes: de68bab4 ("usb: Don't enable USB 2.0 Link PM by default.”) Signed-off-by:
Kai-Heng Feng <kai.heng.feng@canonical.com> Cc: stable <stable@vger.kernel.org> # after much soaking Signed-off-by:
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Kai-Heng Feng authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 7529b257 upstream. Use new helpers to make LPM enabling/disabling more clear. This is a preparation to subsequent patch. Signed-off-by:
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NeilBrown authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit d58431ea upstream. A recent commit added a call to cache_fresh_locked() when an expired item was found. The call sets the CACHE_VALID flag, so it is important that the item actually is valid. There are two ways it could be valid: 1/ If ->update has been called to fill in relevant content 2/ if CACHE_NEGATIVE is set, to say that content doesn't exist. An expired item that is waiting for an update will be neither. Setting CACHE_VALID will mean that a subsequent call to cache_put() will be likely to dereference uninitialised pointers. So we must make sure the item is valid, and we already have code to do that in try_to_negate_entry(). This takes the hash lock and so cannot be used directly, so take out the two lines that we need and use them. Now cache_fresh_locked() is certain to be called only on a valid item. Cc: stable@kernel.org # 2.6.35 Fixes: 4ecd55ea ("sunrpc: fix cache_head leak due to queued request") Signed-off-by:
NeilBrown <neilb@suse.com> Signed-off-by:
J. Bruce Fields <bfields@redhat.com> Signed-off-by:
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Trond Myklebust authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit e6abc8ca upstream. If there are multiple callbacks queued, waiting for the callback slot when the callback gets shut down, then they all currently end up acting as if they hold the slot, and call nfsd4_cb_sequence_done() resulting in interesting side-effects. In addition, the 'retry_nowait' path in nfsd4_cb_sequence_done() causes a loop back to nfsd4_cb_prepare() without first freeing the slot, which causes a deadlock when nfsd41_cb_get_slot() gets called a second time. This patch therefore adds a boolean to track whether or not the callback did pick up the slot, so that it can do the right thing in these 2 cases. Cc: stable@vger.kernel.org Signed-off-by:
Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by:
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Yan, Zheng authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 37659182 upstream. We missed two places that i_wrbuffer_ref_head, i_wr_ref, i_dirty_caps and i_flushing_caps may change. When they are all zeros, we should free i_head_snapc. Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/38224Reported-and-tested-by:
Luis Henriques <lhenriques@suse.com> Signed-off-by:
"Yan, Zheng" <zyan@redhat.com> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Signed-off-by:
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Jeff Layton authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 76a495d6 upstream. Take the d_lock here to ensure that d_name doesn't change. Cc: stable@vger.kernel.org Signed-off-by:
Jeff Layton <jlayton@kernel.org> Reviewed-by:
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Xie XiuQi authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit a860fa7b upstream. sched_clock_cpu() may not be consistent between CPUs. If a task migrates to another CPU, then se.exec_start is set to that CPU's rq_clock_task() by update_stats_curr_start(). Specifically, the new value might be before the old value due to clock skew. So then if in numa_get_avg_runtime() the expression: 'now - p->last_task_numa_placement' ends up as -1, then the divider '*period + 1' in task_numa_placement() is 0 and things go bang. Similar to update_curr(), check if time goes backwards to avoid this. [ peterz: Wrote new changelog. ] [ mingo: Tweaked the code comment. ] Signed-off-by:
Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: cj.chengjian@huawei.com Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20190425080016.GX11158@hirez.programming.kicks-ass.netSigned-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Peter Zijlstra authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit d6097c9e upstream. Unless the very next line is schedule(), or implies it, one must not use preempt_enable_no_resched(). It can cause a preemption to go missing and thereby cause arbitrary delays, breaking the PREEMPT=y invariant. Link: http://lkml.kernel.org/r/20190423200318.GY14281@hirez.programming.kicks-ass.net Cc: Waiman Long <longman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: the arch/x86 maintainers <x86@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: huang ying <huang.ying.caritas@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: stable@vger.kernel.org Fixes: 2c2d7329 ("tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()") Signed-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
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Aurelien Jarno authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 79b4a9cf upstream. Commit 4c21b8fd (MIPS: seccomp: Handle indirect system calls (o32)) added indirect syscall detection for O32 processes running on MIPS64, but it did not work correctly for big endian kernel/processes. The reason is that the syscall number is loaded from ARG1 using the lw instruction while this is a 64-bit value, so zero is loaded instead of the syscall number. Fix the code by using the ld instruction instead. When running a 32-bit processes on a 64 bit CPU, the values are properly sign-extended, so it ensures the value passed to syscall_trace_enter is correct. Recent systemd versions with seccomp enabled whitelist the getpid syscall for their internal processes (e.g. systemd-journald), but call it through syscall(SYS_getpid). This fix therefore allows O32 big endian systems with a 64-bit kernel to run recent systemd versions. Signed-off-by:
Aurelien Jarno <aurelien@aurel32.net> Cc: <stable@vger.kernel.org> # v3.15+ Reviewed-by:
Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by:
Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
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Frank Sorenson authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 652727bb upstream. A path-based rename returning EBUSY will incorrectly try opening the file with a cifs (NT Create AndX) operation on an smb2+ mount, which causes the server to force a session close. If the mount is smb2+, skip the fallback. Signed-off-by:
Frank Sorenson <sorenson@redhat.com> Signed-off-by:
Steve French <stfrench@microsoft.com> CC: Stable <stable@vger.kernel.org> Reviewed-by:
Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by:
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Paolo Bonzini authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 78e546c8 upstream This cannot be returned by KVM_GET_VCPU_EVENTS, so it is okay to return EINVAL. It causes a WARN from exception_type: WARNING: CPU: 3 PID: 16732 at arch/x86/kvm/x86.c:345 exception_type+0x49/0x50 [kvm]() CPU: 3 PID: 16732 Comm: a.out Tainted: G W 4.4.6-300.fc23.x86_64 #1 Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012 0000000000000286 000000006308a48b ffff8800bec7fcf8 ffffffff813b542e 0000000000000000 ffffffffa0966496 ffff8800bec7fd30 ffffffff810a40f2 ffff8800552a8000 0000000000000000 00000000002c267c 0000000000000001 Call Trace: [<ffffffff813b542e>] dump_stack+0x63/0x85 [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0 [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20 [<ffffffffa0924809>] exception_type+0x49/0x50 [kvm] [<ffffffffa0934622>] kvm_arch_vcpu_ioctl_run+0x10a2/0x14e0 [kvm] [<ffffffffa091c04d>] kvm_vcpu_ioctl+0x33d/0x620 [kvm] [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480 [<ffffffff812414a9>] SyS_ioctl+0x79/0x90 [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71 ---[ end trace b1a0391266848f50 ]--- Testcase (beautified/reduced from syzkaller output): #include <unistd.h> #include <sys/syscall.h> #include <string.h> #include <stdint.h> #include <fcntl.h> #include <sys/ioctl.h> #include <linux/kvm.h> long r[31]; int main() { memset(r, -1, sizeof(r)); r[2] = open("/dev/kvm", O_RDONLY); r[3] = ioctl(r[2], KVM_CREATE_VM, 0); r[7] = ioctl(r[3], KVM_CREATE_VCPU, 0); struct kvm_vcpu_events ve = { .exception.injected = 1, .exception.nr = 0xd4 }; r[27] = ioctl(r[7], KVM_SET_VCPU_EVENTS, &ve); r[30] = ioctl(r[7], KVM_RUN, 0); return 0; } Reported-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com> Signed-off-by:
Zubin Mithra <zsm@chromium.org> Signed-off-by:
Sasha Levin <sashal@kernel.org> Signed-off-by:
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Masahiro Yamada authored
BugLink: https://bugs.launchpad.net/bugs/1830176 commit 0294e6f4 upstream. Currently, linker options are tested by the coordination of $(CC) and $(LD) because $(LD) needs some object to link. As commit 86a9df59 ("kbuild: fix linker feature test macros when cross compiling with Clang") addressed, we need to make sure $(CC) and $(LD) agree the underlying architecture of the passed object. This could be a bit complex when we combine tools from different groups. For example, we can use clang for $(CC), but we still need to rely on GCC toolchain for $(LD). So, I was searching for a way of standalone testing of linker options. A trick I found is to use '-v'; this not only prints the version string, but also tests if the given option is recognized. If a given option is supported, $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419 GNU ld (Linaro_Binutils-2017.11) 2.28.2.20170706 $ echo $? 0 If unsupported, $ aarch64-linux-gnu-ld -v --fix-cortex-a53-843419 GNU ld (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04) 2.23.1 aarch64-linux-gnu-ld: unrecognized option '--fix-cortex-a53-843419' aarch64-linux-gnu-ld: use the --help option for usage information $ echo $? 1 Gold works likewise. $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-843419 GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14 masahiro@pug:~/ref/linux$ echo $? 0 $ aarch64-linux-gnu-ld.gold -v --fix-cortex-a53-999999 GNU gold (Linaro_Binutils-2017.11 2.28.2.20170706) 1.14 aarch64-linux-gnu-ld.gold: --fix-cortex-a53-999999: unknown option aarch64-linux-gnu-ld.gold: use the --help option for usage information $ echo $? 1 LLD too. $ ld.lld -v --gc-sections LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 0 $ ld.lld -v --fix-cortex-a53-843419 LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 0 $ ld.lld -v --fix-cortex-a53-999999 ld.lld: error: unknown argument: --fix-cortex-a53-999999 LLD 7.0.0 (http://llvm.org/git/lld.git 4a0e4190e74cea19f8a8dc625ccaebdf8b5d1585) (compatible with GNU linkers) $ echo $? 1 Signed-off-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by:
Nick Desaulniers <ndesaulniers@google.com> [nc: try-run-cached was added later, just use try-run, which is the current mainline state] Signed-off-by:
Nathan Chancellor <natechancellor@gmail.com> Signed-off-by:
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Josh Poimboeuf authored
Fix a minor typo in the MDS documentation: "eanbled" -> "enabled". Reported-by:
Jeff Bastian <jbastian@redhat.com> Signed-off-by:
Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> CVE-2018-12126 CVE-2018-12127 CVE-2018-12130 CVE-2019-11091 (cherry picked from commit 95310e34) Signed-off-by:
Tyler Hicks <tyhicks@canonical.com> Acked-by:
Juerg Haefliger <juerg.haefliger@canonical.com> Acked-by:
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Tyler Hicks authored
Adjust the last two rows in the table that display possible values when MDS mitigation is enabled. They both were slightly innacurate. In addition, convert the table of possible values and their descriptions to a list-table. The simple table format uses the top border of equals signs to determine cell width which resulted in the first column being far too wide in comparison to the second column that contained the majority of the text. Signed-off-by:
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speck for Pawan Gupta authored
Updated the documentation for a new CVE-2019-11091 Microarchitectural Data Sampling Uncacheable Memory (MDSUM) which is a variant of Microarchitectural Data Sampling (MDS). MDS is a family of side channel attacks on internal buffers in Intel CPUs. MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from memory that takes a fault or assist can leave data in a microarchitectural structure that may later be observed using one of the same methods used by MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM. The existing mitigation for MDS applies to MDSUM as well. Signed-off-by:
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by:
Jon Masters <jcm@redhat.com> CVE-2019-11091 (cherry picked from commit e672f8bf) Signed-off-by:
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Tyler Hicks authored
Bring the Ubuntu MDS mitigations in sync with the upstream mitigations. The initial Ubuntu backport was based on the next to last revision of the base patch series from upstream. There is no functional change except for adjusting L1TF warning messages to use the new URL for the L1TF admin guide. The Atom Silvermont and Airmont changes in the cpu_vuln_whitelist[] cause no functional changes because Silvermont and Airmont do not support Intel Hyper-Threading. Therefore, even without this change, the CPU buffers would be properly flushed as the CPU thread goes into sleep state and MDS would be reported as being mitigated. This commit contains changes from the following upstream commits: 5999bbe7 ("Documentation: Add MDS vulnerability documentation") 65fd4cb6 ("Documentation: Move L1TF to separate directory") bc124170 ("x86/speculation/mds: Add mitigation control for MDS") 22dd8365 ("x86/speculation/mds: Add mitigation mode VMWERV") e261f209 ("x86/speculation/mds: Add BUG_MSBDS_ONLY") CVE-2018-12126 CVE-2018-12127 CVE-2018-12130 CVE-2019-11091 Signed-off-by:
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Khalid Elmously authored
Signed-off-by:Khalid Elmously <khalid.elmously@canonical.com>
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Khalid Elmously authored
BugLink: https://bugs.launchpad.net/bugs/1834030Signed-off-by:
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Khalid Elmously authored
Ignore: yes Signed-off-by: -
Eric Dumazet authored
tcp_fragment() might be called for skbs in the write queue. Memory limits might have been exceeded because tcp_sendmsg() only checks limits at full skb (64KB) boundaries. Therefore, we need to make sure tcp_fragment() wont punish applications that might have setup very low SO_SNDBUF values. Fixes: f070ef2a ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by:
Eric Dumazet <edumazet@google.com> Reported-by:
Christoph Paasch <cpaasch@apple.com> Tested-by:
David S. Miller <davem@davemloft.net> CVE-2019-11478 (backported from commit b6653b36) [tyhicks: Don't enforce the limit on the skb that tcp_send_head points as that skb has never been sent out. In newer kernels containing commit 75c119af ("tcp: implement rb-tree based retransmit queue"), where there the retransmission queue is separate from the write queue, this skb would be in the write queue. With the modified check in this backported patch, we run the risk of enforcing the memory limit on an skb that is after tcp_send_head in the queue yet has never been sent out. However, an inspection of all tcp_fragment() call sites finds that this shouldn't occur and the limit will only be enforced on skbs that are up for retransmission.] Signed-off-by:
Jay Vosburgh <jay.vosburgh@canonical.com> Acked-by:
Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by:
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Eric Dumazet authored
If mtu probing is enabled tcp_mtu_probing() could very well end up with a too small MSS. Use the new sysctl tcp_min_snd_mss to make sure MSS search is performed in an acceptable range. Signed-off-by:
Jonathan Lemon <jonathan.lemon@gmail.com> Cc: Jonathan Looney <jtl@netflix.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Bruce Curtis <brucec@netflix.com> CVE-2019-11479 [tyhicks: Minor context changes due to missing cleanup commit d0f36847 ("tcp: tcp_mtu_probing() cleanup")] Signed-off-by:
Stefan Bader <stefan.bader@canonical.com>
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Eric Dumazet authored
Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. Signed-off-by:
Jonathan Looney <jtl@netflix.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Bruce Curtis <brucec@netflix.com> Cc: Jonathan Lemon <jonathan.lemon@gmail.com> CVE-2019-11479 [tyhicks: Minor context adjustments in ipv4.h and sysctl_net_ipv4.c] Signed-off-by:
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- 11 Jun, 2019 2 commits
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Stefan Bader authored
Signed-off-by: -
Joao Martins authored
v4.15 or since commit 737ff314 ("tcp: use sequence distance to detect reordering") had switched from the packet-based FACK tracking and switched to sequence-based. v4.14 and older still have the old logic and hence on tcp_skb_shift_data() needs to retain its original logic and have @fack_count in sync. In other words, we keep the increment of pcount with tcp_skb_pcount(skb) to later used that to update fack_count. To make it more explicit we track the new skb that gets incremented to pcount in @next_pcount, and we get to avoid the constant invocation of tcp_skb_pcount(skb) all together. Reported-by:
Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by:
Joao Martins <joao.m.martins@oracle.com> BugLink: https://bugs.launchpad.net/bugs/1831637 (Remote denial of service (system crash) caused by integer overflow in TCP SACK handling (LP: #1831637)) Signed-off-by:
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- 05 Jun, 2019 3 commits
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Eric Dumazet authored
Jonathan Looney reported that a malicious peer can force a sender to fragment its retransmit queue into tiny skbs, inflating memory usage and/or overflow 32bit counters. TCP allows an application to queue up to sk_sndbuf bytes, so we need to give some allowance for non malicious splitting of retransmit queue. A new SNMP counter is added to monitor how many times TCP did not allow to split an skb if the allowance was exceeded. Signed-off-by:
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Eric Dumazet authored
Jonathan Looney reported that TCP can trigger the following crash in tcp_shifted_skb() : BUG_ON(tcp_skb_pcount(skb) < pcount); This can happen if the remote peer has advertized the smallest MSS that linux TCP accepts : 48 An skb can hold 17 fragments, and each fragment can hold 32KB on x86, or 64KB on PowerPC. This means that the 16bit witdh of TCP_SKB_CB(skb)->tcp_gso_segs can overflow. Note that tcp_sendmsg() builds skbs with less than 64KB of payload, so this problem needs SACK to be enabled. SACK blocks allow TCP to coalesce multiple skbs in the retransmit queue, thus filling the 17 fragments to maximal capacity. Fixes: 832d11c5 ("tcp: Try to restore large SKBs while SACK processing") Signed-off-by:
Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Bruce Curtis <brucec@netflix.com> BugLink: https://bugs.launchpad.net/bugs/1831637 (Remote denial of service (system crash) caused by integer overflow in TCP SACK handling (LP: #1831637)) [tyhicks: Backport to Xenial: - Adjust context in linux/tcp.h and tcp.c - tcp_shifted_skb() doesn't take the prev skb as a parameter - tcp_collapse_retrans() doesn't do frag shifting since commit f8071cde ("tcp: enhance tcp_collapse_retrans() with skb_shift()") isn't present so no changes are needed to that function] Signed-off-by:
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Stefan Bader authored
Ignore: yes Signed-off-by:
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- 29 May, 2019 4 commits
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Khalid Elmously authored
Signed-off-by: -
Khalid Elmously authored
BugLink: https://bugs.launchpad.net/bugs/1830941Signed-off-by:
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Khalid Elmously authored
Ignore: yes Signed-off-by: -
Alistair Strachan authored
BugLink: https://bugs.launchpad.net/bugs/1830890 Commit 379d98dd ("x86: vdso: Use $LD instead of $CC to link") accidentally broke unwinding from userspace, because ld would strip the .eh_frame sections when linking. Originally, the compiler would implicitly add --eh-frame-hdr when invoking the linker, but when this Makefile was converted from invoking ld via the compiler, to invoking it directly (like vmlinux does), the flag was missed. (The EH_FRAME section is important for the VDSO shared libraries, but not for vmlinux.) Fix the problem by explicitly specifying --eh-frame-hdr, which restores parity with the old method. See relevant bug reports for additional info: https://bugzilla.kernel.org/show_bug.cgi?id=201741 https://bugzilla.redhat.com/show_bug.cgi?id=1659295 Fixes: 379d98dd ("x86: vdso: Use $LD instead of $CC to link") Reported-by:
Florian Weimer <fweimer@redhat.com> Reported-by:
Carlos O'Donell <carlos@redhat.com> Reported-by:
"H. J. Lu" <hjl.tools@gmail.com> Signed-off-by:
Alistair Strachan <astrachan@google.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Tested-by:
Laura Abbott <labbott@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Carlos O'Donell <carlos@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: kernel-team@android.com Cc: Laura Abbott <labbott@redhat.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: X86 ML <x86@kernel.org> Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@google.com (cherry picked from commit cd01544a) Signed-off-by:
Connor Kuehl <connor.kuehl@canonical.com> Acked-by: Colin Ian King <colin.king at canonical.com> Acked-by:
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