- Oct 07, 2022
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Greg Kroah-Hartman authored
Link: https://lore.kernel.org/r/20221005113210.255710920@linuxfoundation.org Reviewed-by:
Guenter Roeck <linux@roeck-us.net> Tested-by:
Jon Hunter <jonathanh@nvidia.com> Tested-by:
Linux Kernel Functional Testing <lkft@linaro.org> Tested-by:
Slade Watkins <srw@sladewatkins.net> Tested-by:
Allen Pais <apais@linux.microsoft.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Shuah Khan authored
commit 8bfdfa0d upstream. Update mediator information in the CoC interpretation document. Signed-off-by:
Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/r/20220901212319.56644-1-skhan@linuxfoundation.org Cc: stable@vger.kernel.org Signed-off-by:
Jonathan Corbet <corbet@lwn.net> Signed-off-by:
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Sami Tolvanen authored
commit 21206351 upstream. We enable -Wcast-function-type globally in the kernel to warn about mismatching types in function pointer casts. Compilers currently warn only about ABI incompability with this flag, but Clang 16 will enable a stricter version of the check by default that checks for an exact type match. This will be very noisy in the kernel, so disable -Wcast-function-type-strict without W=1 until the new warnings have been addressed. Cc: stable@vger.kernel.org Link: https://reviews.llvm.org/D134831 Link: https://github.com/ClangBuiltLinux/linux/issues/1724 Suggested-by:
Nathan Chancellor <nathan@kernel.org> Signed-off-by:
Sami Tolvanen <samitolvanen@google.com> Signed-off-by:
Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220930203310.4010564-1-samitolvanen@google.com Signed-off-by:
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Greg Kroah-Hartman authored
This reverts commit c89849ec which is commit 66f99628 upstream. It is reported to cause problems on 5.4.y so it should be reverted for now. Reported-by:
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YueHaibing authored
commit b3531f5f upstream. fs/xfs/xfs_inode.c: In function 'xfs_itruncate_extents_flags': fs/xfs/xfs_inode.c:1523:8: warning: unused variable 'done' [-Wunused-variable] commit 4bbb04ab ("xfs: truncate should remove all blocks, not just to the end of the page cache") left behind this, so remove it. Fixes: 4bbb04ab ("xfs: truncate should remove all blocks, not just to the end of the page cache") Reported-by:
Hulk Robot <hulkci@huawei.com> Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Reviewed-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
Darrick J. Wong <djwong@kernel.org> Signed-off-by:
Chandan Babu R <chandan.babu@oracle.com> Signed-off-by:
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Darrick J. Wong authored
commit 54027a49 upstream. Dan Carpenter pointed out that error is uninitialized. While there never should be an attr leaf block with zero entries, let's not leave that logic bomb there. Fixes: 0bb9d159 ("xfs: streamline xfs_attr3_leaf_inactive") Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
Allison Collins <allison.henderson@oracle.com> Reviewed-by:
Eric Sandeen <sandeen@redhat.com> Acked-by:
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Darrick J. Wong authored
commit 0bb9d159 upstream. Now that we know we don't have to take a transaction to stale the incore buffers for a remote value, get rid of the unnecessary memory allocation in the leaf walker and call the rmt_stale function directly. Flatten the loop while we're at it. Signed-off-by:
Christoph Hellwig <hch@lst.de> Acked-by:
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Christoph Hellwig authored
commit a39f089a upstream. Move the abstract in-memory version of various btree block headers out of xfs_da_format.h as they aren't on-disk formats. Signed-off-by:
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Darrick J. Wong authored
commit e8db2aaf upstream. [Replaced XFS_IS_CORRUPT() calls with ASSERT() for 5.4.y backport] While running generic/103, I observed what looks like memory corruption and (with slub debugging turned on) a slub redzone warning on i386 when inactivating an inode with a 64k remote attr value. On a v5 filesystem, maximally sized remote attr values require one block more than 64k worth of space to hold both the remote attribute value header (64 bytes). On a 4k block filesystem this results in a 68k buffer; on a 64k block filesystem, this would be a 128k buffer. Note that even though we'll never use more than 65,600 bytes of this buffer, XFS_MAX_BLOCKSIZE is 64k. This is a problem because the definition of struct xfs_buf_log_format allows for XFS_MAX_BLOCKSIZE worth of dirty bitmap (64k). On i386 when we invalidate a remote attribute, xfs_trans_binval zeroes all 68k worth of the dirty map, writing right off the end of the log item and corrupting memory. We've gotten away with this on x86_64 for years because the compiler inserts a u32 padding on the end of struct xfs_buf_log_format. Fortunately for us, remote attribute values are written to disk with xfs_bwrite(), which is to say that they are not logged. Fix the problem by removing all places where we could end up creating a buffer log item for a remote attribute value and leave a note explaining why. Next, replace the open-coded buffer invalidation with a call to the helper we created in the previous patch that does better checking for bad metadata before marking the buffer stale. Signed-off-by:
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Darrick J. Wong authored
commit 8edbb26b upstream. [Replaced XFS_IS_CORRUPT() calls with ASSERT() for 5.4.y backport] Hoist the code that invalidates remote extended attribute value buffers into a separate helper function. This prepares us for a memory corruption fix in the next patch. Signed-off-by:
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Christoph Hellwig authored
commit 7b53b868 upstream. Direct I/O reads can also be used with RWF_NOWAIT & co. Fix the inode locking in xfs_file_dio_aio_read to take IOCB_NOWAIT into account. Signed-off-by:
Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by:
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Darrick J. Wong authored
commit 932befe3 upstream. I observed a hang in generic/308 while running fstests on a i686 kernel. The hang occurred when trying to purge the pagecache on a large sparse file that had a page created past MAX_LFS_FILESIZE, which caused an integer overflow in the pagecache xarray and resulted in an infinite loop. I then noticed that Linus changed the definition of MAX_LFS_FILESIZE in commit 0cc3b0ec ("Clarify (and fix) MAX_LFS_FILESIZE macros") so that it is now one page short of the maximum page index on 32-bit kernels. Because the XFS function to compute max offset open-codes the 2005-era MAX_LFS_FILESIZE computation and neither the vfs nor mm perform any sanity checking of s_maxbytes, the code in generic/308 can create a page above the pagecache's limit and kaboom. Fix all this by setting s_maxbytes to MAX_LFS_FILESIZE directly and aborting the mount with a warning if our assumptions ever break. I have no answer for why this seems to have been broken for years and nobody noticed. Signed-off-by:
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Darrick J. Wong authored
commit 4bbb04ab upstream. xfs_itruncate_extents_flags() is supposed to unmap every block in a file from EOF onwards. Oddly, it uses s_maxbytes as the upper limit to the bunmapi range, even though s_maxbytes reflects the highest offset the pagecache can support, not the highest offset that XFS supports. The result of this confusion is that if you create a 20T file on a 64-bit machine, mount the filesystem on a 32-bit machine, and remove the file, we leak everything above 16T. Fix this by capping the bunmapi request at the maximum possible block offset, not s_maxbytes. Signed-off-by:
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Darrick J. Wong authored
commit a5084865 upstream. Introduce a new #define for the maximum supported file block offset. We'll use this in the next patch to make it more obvious that we're doing some operation for all possible inode fork mappings after a given offset. We can't use ULLONG_MAX here because bunmapi uses that to detect when it's done. Signed-off-by:
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Christoph Hellwig authored
commit 780d2905 upstream. XFS_ATTR_INCOMPLETE is a flag in the on-disk attribute format, and thus in a different namespace as the ATTR_* flags in xfs_da_args.flags. Switch to using a XFS_DA_OP_INCOMPLETE flag in op_flags instead. Without this users might be able to inject this flag into operations using the attr by handle ioctl. Signed-off-by:
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Daniel Sneddon authored
commit 2b129932 upstream. tl;dr: The Enhanced IBRS mitigation for Spectre v2 does not work as documented for RET instructions after VM exits. Mitigate it with a new one-entry RSB stuffing mechanism and a new LFENCE. == Background == Indirect Branch Restricted Speculation (IBRS) was designed to help mitigate Branch Target Injection and Speculative Store Bypass, i.e. Spectre, attacks. IBRS prevents software run in less privileged modes from affecting branch prediction in more privileged modes. IBRS requires the MSR to be written on every privilege level change. To overcome some of the performance issues of IBRS, Enhanced IBRS was introduced. eIBRS is an "always on" IBRS, in other words, just turn it on once instead of writing the MSR on every privilege level change. When eIBRS is enabled, more privileged modes should be protected from less privileged modes, including protecting VMMs from guests. == Problem == Here's a simplification of how guests are run on Linux' KVM: void run_kvm_guest(void) { // Prepare to run guest VMRESUME(); // Clean up after guest runs } The execution flow for that would look something like this to the processor: 1. Host-side: call run_kvm_guest() 2. Host-side: VMRESUME 3. Guest runs, does "CALL guest_function" 4. VM exit, host runs again 5. Host might make some "cleanup" function calls 6. Host-side: RET from run_kvm_guest() Now, when back on the host, there are a couple of possible scenarios of post-guest activity the host needs to do before executing host code: * on pre-eIBRS hardware (legacy IBRS, or nothing at all), the RSB is not touched and Linux has to do a 32-entry stuffing. * on eIBRS hardware, VM exit with IBRS enabled, or restoring the host IBRS=1 shortly after VM exit, has a documented side effect of flushing the RSB except in this PBRSB situation where the software needs to stuff the last RSB entry "by hand". IOW, with eIBRS supported, host RET instructions should no longer be influenced by guest behavior after the host retires a single CALL instruction. However, if the RET instructions are "unbalanced" with CALLs after a VM exit as is the RET in #6, it might speculatively use the address for the instruction after the CALL in #3 as an RSB prediction. This is a problem since the (untrusted) guest controls this address. Balanced CALL/RET instruction pairs such as in step #5 are not affected. == Solution == The PBRSB issue affects a wide variety of Intel processors which support eIBRS. But not all of them need mitigation. Today, X86_FEATURE_RSB_VMEXIT triggers an RSB filling sequence that mitigates PBRSB. Systems setting RSB_VMEXIT need no further mitigation - i.e., eIBRS systems which enable legacy IBRS explicitly. However, such systems (X86_FEATURE_IBRS_ENHANCED) do not set RSB_VMEXIT and most of them need a new mitigation. Therefore, introduce a new feature flag X86_FEATURE_RSB_VMEXIT_LITE which triggers a lighter-weight PBRSB mitigation versus RSB_VMEXIT. The lighter-weight mitigation performs a CALL instruction which is immediately followed by a speculative execution barrier (INT3). This steers speculative execution to the barrier -- just like a retpoline -- which ensures that speculation can never reach an unbalanced RET. Then, ensure this CALL is retired before continuing execution with an LFENCE. In other words, the window of exposure is opened at VM exit where RET behavior is troublesome. While the window is open, force RSB predictions sampling for RET targets to a dead end at the INT3. Close the window with the LFENCE. There is a subset of eIBRS systems which are not vulnerable to PBRSB. Add these systems to the cpu_vuln_whitelist[] as NO_EIBRS_PBRSB. Future systems that aren't vulnerable will set ARCH_CAP_PBRSB_NO. [ bp: Massage, incorporate review comments from Andy Cooper. ] Signed-off-by:
Daniel Sneddon <daniel.sneddon@linux.intel.com> Co-developed-by:
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by:
Borislav Petkov <bp@suse.de> [cascardo: no intra-function validation] Signed-off-by:
Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by:
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Pawan Gupta authored
commit eb23b5ef upstream. IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at every kernel entry/exit. On Enhanced IBRS parts setting MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at every kernel entry/exit incur unnecessary performance loss. When Enhanced IBRS feature is present, print a warning about this unnecessary performance loss. Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
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Nathan Chancellor authored
commit db886979 upstream. Clang warns: arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection] DEFINE_PER_CPU(u64, x86_spec_ctrl_current); ^ arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here extern u64 x86_spec_ctrl_current; ^ 1 error generated. The declaration should be using DECLARE_PER_CPU instead so all attributes stay in sync. Cc: stable@vger.kernel.org Fixes: fc02735b ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Pawan Gupta authored
commit 4ad3278d upstream. Some Intel processors may use alternate predictors for RETs on RSB-underflow. This condition may be vulnerable to Branch History Injection (BHI) and intramode-BTI. Kernel earlier added spectre_v2 mitigation modes (eIBRS+Retpolines, eIBRS+LFENCE, Retpolines) which protect indirect CALLs and JMPs against such attacks. However, on RSB-underflow, RET target prediction may fallback to alternate predictors. As a result, RET's predicted target may get influenced by branch history. A new MSR_IA32_SPEC_CTRL bit (RRSBA_DIS_S) controls this fallback behavior when in kernel mode. When set, RETs will not take predictions from alternate predictors, hence mitigating RETs as well. Support for this is enumerated by CPUID.7.2.EDX[RRSBA_CTRL] (bit2). For spectre v2 mitigation, when a user selects a mitigation that protects indirect CALLs and JMPs against BHI and intramode-BTI, set RRSBA_DIS_S also to protect RETs for RSB-underflow case. Signed-off-by:
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Pawan Gupta authored
commit f54d4537 upstream. Cannon lake is also affected by RETBleed, add it to the list. Fixes: 6ad0ad2b ("x86/bugs: Report Intel retbleed vulnerability") Signed-off-by:
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Andrew Cooper authored
commit 26aae8cc upstream. BTC_NO indicates that hardware is not susceptible to Branch Type Confusion. Zen3 CPUs don't suffer BTC. Hypervisors are expected to synthesise BTC_NO when it is appropriate given the migration pool, to prevent kernels using heuristics. [ bp: Massage. ] Signed-off-by:
Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by:
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Peter Zijlstra authored
commit 7a05bc95 upstream. The whole MMIO/RETBLEED enumeration went overboard on steppings. Get rid of all that and simply use ANY. If a future stepping of these models would not be affected, it had better set the relevant ARCH_CAP_$FOO_NO bit in IA32_ARCH_CAPABILITIES. Signed-off-by:
Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by:
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Josh Poimboeuf authored
commit 9756bba2 upstream. Prevent RSB underflow/poisoning attacks with RSB. While at it, add a bunch of comments to attempt to document the current state of tribal knowledge about RSB attacks and what exactly is being mitigated. Signed-off-by:
Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by:
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Josh Poimboeuf authored
commit bea7e31a upstream. For legacy IBRS to work, the IBRS bit needs to be always re-written after vmexit, even if it's already on. Signed-off-by:
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Josh Poimboeuf authored
commit fc02735b upstream. On eIBRS systems, the returns in the vmexit return path from __vmx_vcpu_run() to vmx_vcpu_run() are exposed to RSB poisoning attacks. Fix that by moving the post-vmexit spec_ctrl handling to immediately after the vmexit. Signed-off-by:
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Thadeu Lima de Souza Cascardo authored
commit bb066506 upstream. Convert __vmx_vcpu_run()'s 'launched' argument to 'flags', in preparation for doing SPEC_CTRL handling immediately after vmexit, which will need another flag. This is much easier than adding a fourth argument, because this code supports both 32-bit and 64-bit, and the fourth argument on 32-bit would have to be pushed on the stack. Note that __vmx_vcpu_run_flags() is called outside of the noinstr critical section because it will soon start calling potentially traceable functions. Signed-off-by:
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Josh Poimboeuf authored
commit 8bd200d2 upstream. Move the vmx_vm{enter,exit}() functionality into __vmx_vcpu_run(). This will make it easier to do the spec_ctrl handling before the first RET. Signed-off-by:
Ben Hutchings <ben@decadent.org.uk> Signed-off-by:
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Uros Bizjak authored
commit 150f17bf upstream. Replace inline assembly in nested_vmx_check_vmentry_hw with a call to __vmx_vcpu_run. The function is not performance critical, so (double) GPR save/restore in __vmx_vcpu_run can be tolerated, as far as performance effects are concerned. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Reviewed-and-tested-by:
Sean Christopherson <seanjc@google.com> Signed-off-by:
Uros Bizjak <ubizjak@gmail.com> [sean: dropped versioning info from changelog] Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> [cascardo: small fixups] Signed-off-by:
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Uros Bizjak authored
commit 6c44221b upstream. Saves one byte in __vmx_vcpu_run for the same functionality. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:
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Josh Poimboeuf authored
commit acac5e98 upstream. This mask has been made redundant by kvm_spec_ctrl_test_value(). And it doesn't even work when MSR interception is disabled, as the guest can just write to SPEC_CTRL directly. Signed-off-by:
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Josh Poimboeuf authored
commit bbb69e8b upstream. There's no need to recalculate the host value for every entry/exit. Just use the cached value in spec_ctrl_current(). Signed-off-by:
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Josh Poimboeuf authored
commit 56aa4d22 upstream. If the SMT state changes, SSBD might get accidentally disabled. Fix that. Signed-off-by:
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Josh Poimboeuf authored
commit e6aa1362 upstream. The firmware entry code may accidentally clear STIBP or SSBD. Fix that. Signed-off-by:
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Josh Poimboeuf authored
commit b2620fac upstream. If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be silently disabled. There's nothing retpoline-specific about RSB buffer filling. Remove the CONFIG_RETPOLINE guards around it. Signed-off-by:
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Peter Zijlstra authored
commit 089dd8e5 upstream. Change FILL_RETURN_BUFFER so that objtool groks it and can generate correct ORC unwind information. - Since ORC is alternative invariant; that is, all alternatives should have the same ORC entries, the __FILL_RETURN_BUFFER body can not be part of an alternative. Therefore, move it out of the alternative and keep the alternative as a sort of jump_label around it. - Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list these 'funny' call instructions to nowhere. - Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise objtool will consider them unreachable. - Move the RSP adjustment into the loop, such that the loop has a deterministic stack layout. Signed-off-by:
Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by:
Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200428191700.032079304@infradead.org [cascardo: fixup because of backport of ba6e31af ("x86/speculation: Add LFENCE to RSB fill sequence")] [cascardo: no intra-function call validation support] [cascardo: avoid UNWIND_HINT_EMPTY because of svm] Signed-off-by:
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Peter Zijlstra authored
commit bf5835bc upstream. Having IBRS enabled while the SMT sibling is idle unnecessarily slows down the running sibling. OTOH, disabling IBRS around idle takes two MSR writes, which will increase the idle latency. Therefore, only disable IBRS around deeper idle states. Shallow idle states are bounded by the tick in duration, since NOHZ is not allowed for them by virtue of their short target residency. Only do this for mwait-driven idle, since that keeps interrupts disabled across idle, which makes disabling IBRS vs IRQ-entry a non-issue. Note: C6 is a random threshold, most importantly C1 probably shouldn't disable IBRS, benchmarking needed. Suggested-by:
Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by:
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Peter Zijlstra authored
commit 6ad0ad2b upstream. Skylake suffers from RSB underflow speculation issues; report this vulnerability and it's mitigation (spectre_v2=ibrs). [jpoimboe: cleanups, eibrs] Signed-off-by:
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Peter Zijlstra authored
commit 166115c0 upstream. retbleed will depend on spectre_v2, while spectre_v2_user depends on retbleed. Break this cycle. Signed-off-by:
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Pawan Gupta authored
commit 7c693f54 upstream. Extend spectre_v2= boot option with Kernel IBRS. [jpoimboe: no STIBP with IBRS] Signed-off-by:
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Peter Zijlstra authored
commit c779bc1a upstream. When changing SPEC_CTRL for user control, the WRMSR can be delayed until return-to-user when KERNEL_IBRS has been enabled. This avoids an MSR write during context switch. Signed-off-by:
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