diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/hw-vuln/spectre.rst | 88 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 8 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/spi/spi-controller.yaml | 1 | ||||
| -rw-r--r-- | Documentation/filesystems/cifs/TODO | 26 | ||||
| -rw-r--r-- | Documentation/networking/tls-offload.rst | 23 |
5 files changed, 117 insertions, 29 deletions
diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst index 25f3b2532198..e05e581af5cf 100644 --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -41,10 +41,11 @@ Related CVEs The following CVE entries describe Spectre variants: - ============= ======================= ================= + ============= ======================= ========================== CVE-2017-5753 Bounds check bypass Spectre variant 1 CVE-2017-5715 Branch target injection Spectre variant 2 - ============= ======================= ================= + CVE-2019-1125 Spectre v1 swapgs Spectre variant 1 (swapgs) + ============= ======================= ========================== Problem ------- @@ -78,6 +79,13 @@ There are some extensions of Spectre variant 1 attacks for reading data over the network, see :ref:`[12] <spec_ref12>`. However such attacks are difficult, low bandwidth, fragile, and are considered low risk. +Note that, despite "Bounds Check Bypass" name, Spectre variant 1 is not +only about user-controlled array bounds checks. It can affect any +conditional checks. The kernel entry code interrupt, exception, and NMI +handlers all have conditional swapgs checks. Those may be problematic +in the context of Spectre v1, as kernel code can speculatively run with +a user GS. + Spectre variant 2 (Branch Target Injection) ------------------------------------------- @@ -132,6 +140,9 @@ not cover all possible attack vectors. 1. A user process attacking the kernel ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Spectre variant 1 +~~~~~~~~~~~~~~~~~ + The attacker passes a parameter to the kernel via a register or via a known address in memory during a syscall. Such parameter may be used later by the kernel as an index to an array or to derive @@ -144,7 +155,40 @@ not cover all possible attack vectors. potentially be influenced for Spectre attacks, new "nospec" accessor macros are used to prevent speculative loading of data. - Spectre variant 2 attacker can :ref:`poison <poison_btb>` the branch +Spectre variant 1 (swapgs) +~~~~~~~~~~~~~~~~~~~~~~~~~~ + + An attacker can train the branch predictor to speculatively skip the + swapgs path for an interrupt or exception. If they initialize + the GS register to a user-space value, if the swapgs is speculatively + skipped, subsequent GS-related percpu accesses in the speculation + window will be done with the attacker-controlled GS value. This + could cause privileged memory to be accessed and leaked. + + For example: + + :: + + if (coming from user space) + swapgs + mov %gs:<percpu_offset>, %reg + mov (%reg), %reg1 + + When coming from user space, the CPU can speculatively skip the + swapgs, and then do a speculative percpu load using the user GS + value. So the user can speculatively force a read of any kernel + value. If a gadget exists which uses the percpu value as an address + in another load/store, then the contents of the kernel value may + become visible via an L1 side channel attack. + + A similar attack exists when coming from kernel space. The CPU can + speculatively do the swapgs, causing the user GS to get used for the + rest of the speculative window. + +Spectre variant 2 +~~~~~~~~~~~~~~~~~ + + A spectre variant 2 attacker can :ref:`poison <poison_btb>` the branch target buffer (BTB) before issuing syscall to launch an attack. After entering the kernel, the kernel could use the poisoned branch target buffer on indirect jump and jump to gadget code in speculative @@ -280,11 +324,18 @@ The sysfs file showing Spectre variant 1 mitigation status is: The possible values in this file are: - ======================================= ================================= - 'Mitigation: __user pointer sanitation' Protection in kernel on a case by - case base with explicit pointer - sanitation. - ======================================= ================================= + .. list-table:: + + * - 'Not affected' + - The processor is not vulnerable. + * - 'Vulnerable: __user pointer sanitization and usercopy barriers only; no swapgs barriers' + - The swapgs protections are disabled; otherwise it has + protection in the kernel on a case by case base with explicit + pointer sanitation and usercopy LFENCE barriers. + * - 'Mitigation: usercopy/swapgs barriers and __user pointer sanitization' + - Protection in the kernel on a case by case base with explicit + pointer sanitation, usercopy LFENCE barriers, and swapgs LFENCE + barriers. However, the protections are put in place on a case by case basis, and there is no guarantee that all possible attack vectors for Spectre @@ -366,12 +417,27 @@ Turning on mitigation for Spectre variant 1 and Spectre variant 2 1. Kernel mitigation ^^^^^^^^^^^^^^^^^^^^ +Spectre variant 1 +~~~~~~~~~~~~~~~~~ + For the Spectre variant 1, vulnerable kernel code (as determined by code audit or scanning tools) is annotated on a case by case basis to use nospec accessor macros for bounds clipping :ref:`[2] <spec_ref2>` to avoid any usable disclosure gadgets. However, it may not cover all attack vectors for Spectre variant 1. + Copy-from-user code has an LFENCE barrier to prevent the access_ok() + check from being mis-speculated. The barrier is done by the + barrier_nospec() macro. + + For the swapgs variant of Spectre variant 1, LFENCE barriers are + added to interrupt, exception and NMI entry where needed. These + barriers are done by the FENCE_SWAPGS_KERNEL_ENTRY and + FENCE_SWAPGS_USER_ENTRY macros. + +Spectre variant 2 +~~~~~~~~~~~~~~~~~ + For Spectre variant 2 mitigation, the compiler turns indirect calls or jumps in the kernel into equivalent return trampolines (retpolines) :ref:`[3] <spec_ref3>` :ref:`[9] <spec_ref9>` to go to the target @@ -473,6 +539,12 @@ Mitigation control on the kernel command line Spectre variant 2 mitigation can be disabled or force enabled at the kernel command line. + nospectre_v1 + + [X86,PPC] Disable mitigations for Spectre Variant 1 + (bounds check bypass). With this option data leaks are + possible in the system. + nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2 diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7ccd158b3894..47d981a86e2f 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2604,7 +2604,7 @@ expose users to several CPU vulnerabilities. Equivalent to: nopti [X86,PPC] kpti=0 [ARM64] - nospectre_v1 [PPC] + nospectre_v1 [X86,PPC] nobp=0 [S390] nospectre_v2 [X86,PPC,S390,ARM64] spectre_v2_user=off [X86] @@ -2965,9 +2965,9 @@ nosmt=force: Force disable SMT, cannot be undone via the sysfs control file. - nospectre_v1 [PPC] Disable mitigations for Spectre Variant 1 (bounds - check bypass). With this option data leaks are possible - in the system. + nospectre_v1 [X86,PPC] Disable mitigations for Spectre Variant 1 + (bounds check bypass). With this option data leaks are + possible in the system. nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for the Spectre variant 2 (indirect branch prediction) diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml index 876c0623f322..a02e2fe2bfb2 100644 --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml @@ -73,7 +73,6 @@ patternProperties: Compatible of the SPI device. reg: - maxItems: 1 minimum: 0 maximum: 256 description: diff --git a/Documentation/filesystems/cifs/TODO b/Documentation/filesystems/cifs/TODO index 9267f3fb131f..edbbccda1942 100644 --- a/Documentation/filesystems/cifs/TODO +++ b/Documentation/filesystems/cifs/TODO @@ -13,7 +13,8 @@ a) SMB3 (and SMB3.1.1) missing optional features: - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl currently the only two server side copy mechanisms supported) -b) improved sparse file support +b) improved sparse file support (fiemap and SEEK_HOLE are implemented +but additional features would be supportable by the protocol). c) Directory entry caching relies on a 1 second timer, rather than using Directory Leases, currently only the root file handle is cached longer @@ -21,9 +22,13 @@ using Directory Leases, currently only the root file handle is cached longer d) quota support (needs minor kernel change since quota calls to make it to network filesystems or deviceless filesystems) -e) Additional use cases where we use "compoounding" (e.g. open/query/close -and open/setinfo/close) to reduce the number of roundtrips, and also -open to reduce redundant opens (using deferred close and reference counts more). +e) Additional use cases can be optimized to use "compounding" +(e.g. open/query/close and open/setinfo/close) to reduce the number +of roundtrips to the server and improve performance. Various cases +(stat, statfs, create, unlink, mkdir) already have been improved by +using compounding but more can be done. In addition we could significantly +reduce redundant opens by using deferred close (with handle caching leases) +and better using reference counters on file handles. f) Finish inotify support so kde and gnome file list windows will autorefresh (partially complete by Asser). Needs minor kernel @@ -43,18 +48,17 @@ mount or a per server basis to client UIDs or nobody if no mapping exists. Also better integration with winbind for resolving SID owners k) Add tools to take advantage of more smb3 specific ioctls and features -(passthrough ioctl/fsctl for sending various SMB3 fsctls to the server -is in progress, and a passthrough query_info call is already implemented -in cifs.ko to allow smb3 info levels queries to be sent from userspace) +(passthrough ioctl/fsctl is now implemented in cifs.ko to allow sending +various SMB3 fsctls and query info and set info calls directly from user space) +Add tools to make setting various non-POSIX metadata attributes easier +from tools (e.g. extending what was done in smb-info tool). l) encrypted file support m) improved stats gathering tools (perhaps integration with nfsometer?) to extend and make easier to use what is currently in /proc/fs/cifs/Stats -n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed -file attribute via chflags) and improve user space tools for managing and -viewing them. +n) Add support for claims based ACLs ("DAC") o) mount helper GUI (to simplify the various configuration options on mount) @@ -82,6 +86,8 @@ so far). w) Add support for additional strong encryption types, and additional spnego authentication mechanisms (see MS-SMB2) +x) Finish support for SMB3.1.1 compression + KNOWN BUGS ==================================== See http://bugzilla.samba.org - search on product "CifsVFS" for diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst index 048e5ca44824..b70b70dc4524 100644 --- a/Documentation/networking/tls-offload.rst +++ b/Documentation/networking/tls-offload.rst @@ -424,13 +424,24 @@ Statistics Following minimum set of TLS-related statistics should be reported by the driver: - * ``rx_tls_decrypted`` - number of successfully decrypted TLS segments - * ``tx_tls_encrypted`` - number of in-order TLS segments passed to device - for encryption + * ``rx_tls_decrypted_packets`` - number of successfully decrypted RX packets + which were part of a TLS stream. + * ``rx_tls_decrypted_bytes`` - number of TLS payload bytes in RX packets + which were successfully decrypted. + * ``tx_tls_encrypted_packets`` - number of TX packets passed to the device + for encryption of their TLS payload. + * ``tx_tls_encrypted_bytes`` - number of TLS payload bytes in TX packets + passed to the device for encryption. + * ``tx_tls_ctx`` - number of TLS TX HW offload contexts added to device for + encryption. * ``tx_tls_ooo`` - number of TX packets which were part of a TLS stream - but did not arrive in the expected order - * ``tx_tls_drop_no_sync_data`` - number of TX packets dropped because - they arrived out of order and associated record could not be found + but did not arrive in the expected order. + * ``tx_tls_drop_no_sync_data`` - number of TX packets which were part of + a TLS stream dropped, because they arrived out of order and associated + record could not be found. + * ``tx_tls_drop_bypass_req`` - number of TX packets which were part of a TLS + stream dropped, because they contain both data that has been encrypted by + software and data that expects hardware crypto offload. Notable corner cases, exceptions and additional requirements ============================================================ |