| Message ID | 20240411063027.493165-1-andrea.righi@canonical.com |
|---|---|
| Headers | show |
| Series | Apply mitigations for the native BHI hardware vulnerabilty | expand |
On 11.04.24 08:24, Andrea Righi wrote: > BugLink: https://bugs.launchpad.net/bugs/2060909 > > [Impact] > > Branch History Injection (BHI) attacks may allow a malicious application > to influence indirect branch prediction in kernel by poisoning the > branch history. eIBRS isolates indirect branch targets in ring0. > > The BHB can still influence the choice of indirect branch predictor > entry, and although branch predictor entries are isolated between modes > when eIBRS is enabled, the BHB itself is not isolated between modes. > > Previously the only known real-world BHB attack vector was via > unprivileged eBPF. Further research has found attacks that don't require > unprivileged eBPF. > > See also: > https://www.phoronix.com/news/Linux-BHI-Branch-History-Inject > > [Test case] > > https://www.vusec.net/projects/native-bhi/ > > [Fix] > > Backport from upstream the merge that introduces spectre_bhi= boot > option to control BHI mitigation: > > 2bb69f5fc721 ("Merge tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") > ed2e8d49b54d ("KVM: x86: Add BHI_NO") > 95a6ccbdc719 ("x86/bhi: Mitigate KVM by default") > ec9404e40e8f ("x86/bhi: Add BHI mitigation knob") > be482ff95009 ("x86/bhi: Enumerate Branch History Injection (BHI) bug") > 0f4a837615ff ("x86/bhi: Define SPEC_CTRL_BHI_DIS_S") > 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry") > 1e3ad78334a6 ("x86/syscall: Don't force use of indirect calls for system calls") > 0cd01ac5dcb1 ("x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file") > > Also set spectre_bhi=auto by default, that will rely on the BHI_DIS_S > hardware control if it's available on the system CPUs, otherwise a > proper software sequence will be executed at VMexit. > > NOTE: we may get these changes via stable update in 6.8, when that > happens we can drop this backport and apply the patch set like any other > regular stable update. > > [Regression potential] > > We may experience performance regressions with this new mitigation > enabled, especially in VMs and CPUs that don't have the BHI hardware > support capability (due to the extra software sequence executed at > VMexit). > > ---------------------------------------------------------------- > Andrea Righi (1): > UBUNTU: [Config] enable spectre_bhi=auto by default > > Daniel Sneddon (2): > x86/bhi: Define SPEC_CTRL_BHI_DIS_S > KVM: x86: Add BHI_NO > > Josh Poimboeuf (1): > x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file > > Linus Torvalds (1): > x86/syscall: Don't force use of indirect calls for system calls > > Pawan Gupta (4): > x86/bhi: Add support for clearing branch history at syscall entry > x86/bhi: Enumerate Branch History Injection (BHI) bug > x86/bhi: Add BHI mitigation knob > x86/bhi: Mitigate KVM by default > > Sandipan Das (2): > x86/cpufeatures: Add new word for scattered features > perf/x86/amd/lbr: Use freeze based on availability > > Documentation/admin-guide/hw-vuln/spectre.rst | 48 ++++++++++++++++++++++++++++---- > Documentation/admin-guide/kernel-parameters.txt | 12 ++++++++ > arch/x86/Kconfig | 25 +++++++++++++++++ > arch/x86/entry/common.c | 10 +++---- > arch/x86/entry/entry_64.S | 61 +++++++++++++++++++++++++++++++++++++++++ > arch/x86/entry/entry_64_compat.S | 16 +++++++++++ > arch/x86/entry/syscall_32.c | 21 ++++++++++++-- > arch/x86/entry/syscall_64.c | 19 +++++++++++-- > arch/x86/entry/syscall_x32.c | 10 +++++-- > arch/x86/events/amd/core.c | 4 +-- > arch/x86/events/amd/lbr.c | 16 +++++++---- > arch/x86/include/asm/cpufeature.h | 6 ++-- > arch/x86/include/asm/cpufeatures.h | 15 +++++++++- > arch/x86/include/asm/disabled-features.h | 3 +- > arch/x86/include/asm/msr-index.h | 9 +++++- > arch/x86/include/asm/nospec-branch.h | 17 ++++++++++++ > arch/x86/include/asm/required-features.h | 3 +- > arch/x86/include/asm/syscall.h | 11 ++++---- > arch/x86/kernel/cpu/bugs.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------- > arch/x86/kernel/cpu/common.c | 24 ++++++++++------ > arch/x86/kernel/cpu/scattered.c | 2 ++ > arch/x86/kvm/reverse_cpuid.h | 3 +- > arch/x86/kvm/vmx/vmenter.S | 2 ++ > arch/x86/kvm/x86.c | 2 +- > debian.master/config/annotations | 3 ++ > 25 files changed, 402 insertions(+), 61 deletions(-) Acked-by: Stefan Bader <stefan.bader@canonical.com>
We have applied the fixes directly from stable (cherry picked). So, we can drop this one. -Andrea On Thu, Apr 11, 2024 at 11:22:45AM +0200, Stefan Bader wrote: > On 11.04.24 08:24, Andrea Righi wrote: > > BugLink: https://bugs.launchpad.net/bugs/2060909 > > > > [Impact] > > > > Branch History Injection (BHI) attacks may allow a malicious application > > to influence indirect branch prediction in kernel by poisoning the > > branch history. eIBRS isolates indirect branch targets in ring0. > > > > The BHB can still influence the choice of indirect branch predictor > > entry, and although branch predictor entries are isolated between modes > > when eIBRS is enabled, the BHB itself is not isolated between modes. > > > > Previously the only known real-world BHB attack vector was via > > unprivileged eBPF. Further research has found attacks that don't require > > unprivileged eBPF. > > > > See also: > > https://www.phoronix.com/news/Linux-BHI-Branch-History-Inject > > > > [Test case] > > > > https://www.vusec.net/projects/native-bhi/ > > > > [Fix] > > > > Backport from upstream the merge that introduces spectre_bhi= boot > > option to control BHI mitigation: > > > > 2bb69f5fc721 ("Merge tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") > > ed2e8d49b54d ("KVM: x86: Add BHI_NO") > > 95a6ccbdc719 ("x86/bhi: Mitigate KVM by default") > > ec9404e40e8f ("x86/bhi: Add BHI mitigation knob") > > be482ff95009 ("x86/bhi: Enumerate Branch History Injection (BHI) bug") > > 0f4a837615ff ("x86/bhi: Define SPEC_CTRL_BHI_DIS_S") > > 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry") > > 1e3ad78334a6 ("x86/syscall: Don't force use of indirect calls for system calls") > > 0cd01ac5dcb1 ("x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file") > > > > Also set spectre_bhi=auto by default, that will rely on the BHI_DIS_S > > hardware control if it's available on the system CPUs, otherwise a > > proper software sequence will be executed at VMexit. > > > > NOTE: we may get these changes via stable update in 6.8, when that > > happens we can drop this backport and apply the patch set like any other > > regular stable update. > > > > [Regression potential] > > > > We may experience performance regressions with this new mitigation > > enabled, especially in VMs and CPUs that don't have the BHI hardware > > support capability (due to the extra software sequence executed at > > VMexit). > > > > ---------------------------------------------------------------- > > Andrea Righi (1): > > UBUNTU: [Config] enable spectre_bhi=auto by default > > > > Daniel Sneddon (2): > > x86/bhi: Define SPEC_CTRL_BHI_DIS_S > > KVM: x86: Add BHI_NO > > > > Josh Poimboeuf (1): > > x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file > > > > Linus Torvalds (1): > > x86/syscall: Don't force use of indirect calls for system calls > > > > Pawan Gupta (4): > > x86/bhi: Add support for clearing branch history at syscall entry > > x86/bhi: Enumerate Branch History Injection (BHI) bug > > x86/bhi: Add BHI mitigation knob > > x86/bhi: Mitigate KVM by default > > > > Sandipan Das (2): > > x86/cpufeatures: Add new word for scattered features > > perf/x86/amd/lbr: Use freeze based on availability > > > > Documentation/admin-guide/hw-vuln/spectre.rst | 48 ++++++++++++++++++++++++++++---- > > Documentation/admin-guide/kernel-parameters.txt | 12 ++++++++ > > arch/x86/Kconfig | 25 +++++++++++++++++ > > arch/x86/entry/common.c | 10 +++---- > > arch/x86/entry/entry_64.S | 61 +++++++++++++++++++++++++++++++++++++++++ > > arch/x86/entry/entry_64_compat.S | 16 +++++++++++ > > arch/x86/entry/syscall_32.c | 21 ++++++++++++-- > > arch/x86/entry/syscall_64.c | 19 +++++++++++-- > > arch/x86/entry/syscall_x32.c | 10 +++++-- > > arch/x86/events/amd/core.c | 4 +-- > > arch/x86/events/amd/lbr.c | 16 +++++++---- > > arch/x86/include/asm/cpufeature.h | 6 ++-- > > arch/x86/include/asm/cpufeatures.h | 15 +++++++++- > > arch/x86/include/asm/disabled-features.h | 3 +- > > arch/x86/include/asm/msr-index.h | 9 +++++- > > arch/x86/include/asm/nospec-branch.h | 17 ++++++++++++ > > arch/x86/include/asm/required-features.h | 3 +- > > arch/x86/include/asm/syscall.h | 11 ++++---- > > arch/x86/kernel/cpu/bugs.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------- > > arch/x86/kernel/cpu/common.c | 24 ++++++++++------ > > arch/x86/kernel/cpu/scattered.c | 2 ++ > > arch/x86/kvm/reverse_cpuid.h | 3 +- > > arch/x86/kvm/vmx/vmenter.S | 2 ++ > > arch/x86/kvm/x86.c | 2 +- > > debian.master/config/annotations | 3 ++ > > 25 files changed, 402 insertions(+), 61 deletions(-) > > > Acked-by: Stefan Bader <stefan.bader@canonical.com> > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
BugLink: https://bugs.launchpad.net/bugs/2060909 [Impact] Branch History Injection (BHI) attacks may allow a malicious application to influence indirect branch prediction in kernel by poisoning the branch history. eIBRS isolates indirect branch targets in ring0. The BHB can still influence the choice of indirect branch predictor entry, and although branch predictor entries are isolated between modes when eIBRS is enabled, the BHB itself is not isolated between modes. Previously the only known real-world BHB attack vector was via unprivileged eBPF. Further research has found attacks that don't require unprivileged eBPF. See also: https://www.phoronix.com/news/Linux-BHI-Branch-History-Inject [Test case] https://www.vusec.net/projects/native-bhi/ [Fix] Backport from upstream the merge that introduces spectre_bhi= boot option to control BHI mitigation: 2bb69f5fc721 ("Merge tag 'nativebhi' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") ed2e8d49b54d ("KVM: x86: Add BHI_NO") 95a6ccbdc719 ("x86/bhi: Mitigate KVM by default") ec9404e40e8f ("x86/bhi: Add BHI mitigation knob") be482ff95009 ("x86/bhi: Enumerate Branch History Injection (BHI) bug") 0f4a837615ff ("x86/bhi: Define SPEC_CTRL_BHI_DIS_S") 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry") 1e3ad78334a6 ("x86/syscall: Don't force use of indirect calls for system calls") 0cd01ac5dcb1 ("x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file") Also set spectre_bhi=auto by default, that will rely on the BHI_DIS_S hardware control if it's available on the system CPUs, otherwise a proper software sequence will be executed at VMexit. NOTE: we may get these changes via stable update in 6.8, when that happens we can drop this backport and apply the patch set like any other regular stable update. [Regression potential] We may experience performance regressions with this new mitigation enabled, especially in VMs and CPUs that don't have the BHI hardware support capability (due to the extra software sequence executed at VMexit). ---------------------------------------------------------------- Andrea Righi (1): UBUNTU: [Config] enable spectre_bhi=auto by default Daniel Sneddon (2): x86/bhi: Define SPEC_CTRL_BHI_DIS_S KVM: x86: Add BHI_NO Josh Poimboeuf (1): x86/bugs: Change commas to semicolons in 'spectre_v2' sysfs file Linus Torvalds (1): x86/syscall: Don't force use of indirect calls for system calls Pawan Gupta (4): x86/bhi: Add support for clearing branch history at syscall entry x86/bhi: Enumerate Branch History Injection (BHI) bug x86/bhi: Add BHI mitigation knob x86/bhi: Mitigate KVM by default Sandipan Das (2): x86/cpufeatures: Add new word for scattered features perf/x86/amd/lbr: Use freeze based on availability Documentation/admin-guide/hw-vuln/spectre.rst | 48 ++++++++++++++++++++++++++++---- Documentation/admin-guide/kernel-parameters.txt | 12 ++++++++ arch/x86/Kconfig | 25 +++++++++++++++++ arch/x86/entry/common.c | 10 +++---- arch/x86/entry/entry_64.S | 61 +++++++++++++++++++++++++++++++++++++++++ arch/x86/entry/entry_64_compat.S | 16 +++++++++++ arch/x86/entry/syscall_32.c | 21 ++++++++++++-- arch/x86/entry/syscall_64.c | 19 +++++++++++-- arch/x86/entry/syscall_x32.c | 10 +++++-- arch/x86/events/amd/core.c | 4 +-- arch/x86/events/amd/lbr.c | 16 +++++++---- arch/x86/include/asm/cpufeature.h | 6 ++-- arch/x86/include/asm/cpufeatures.h | 15 +++++++++- arch/x86/include/asm/disabled-features.h | 3 +- arch/x86/include/asm/msr-index.h | 9 +++++- arch/x86/include/asm/nospec-branch.h | 17 ++++++++++++ arch/x86/include/asm/required-features.h | 3 +- arch/x86/include/asm/syscall.h | 11 ++++---- arch/x86/kernel/cpu/bugs.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------- arch/x86/kernel/cpu/common.c | 24 ++++++++++------ arch/x86/kernel/cpu/scattered.c | 2 ++ arch/x86/kvm/reverse_cpuid.h | 3 +- arch/x86/kvm/vmx/vmenter.S | 2 ++ arch/x86/kvm/x86.c | 2 +- debian.master/config/annotations | 3 ++ 25 files changed, 402 insertions(+), 61 deletions(-)