kernel/linux.git, branch v6.1.44

Linux 6.1.44

2023-08-08T18:03:51+00:00

Tested-by: Salvatore Bonaccorso Signed-off-by: Greg Kroah-Hartman

x86: fix backwards merge of GDS/SRSO bit

2023-08-08T18:03:51+00:00

Stable-tree-only change. Due to the way the GDS and SRSO patches flowed into the stable tree, it was a 50% chance that the merge of the which value GDS and SRSO should be. Of course, I lost that bet, and chose the opposite of what Linus chose in commit 64094e7e3118 ("Merge tag 'gds-for-linus-2023-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") Fix this up by switching the values to match what is now in Linus's tree as that is the correct value to mirror. Signed-off-by: Greg Kroah-Hartman

xen/netback: Fix buffer overrun triggered by unusual packet

2023-08-08T18:03:51+00:00

commit 534fc31d09b706a16d83533e16b5dc855caf7576 upstream. It is possible that a guest can send a packet that contains a head + 18 slots and yet has a len <= XEN_NETBACK_TX_COPY_LEN. This causes nr_slots to underflow in xenvif_get_requests() which then causes the subsequent loop's termination condition to be wrong, causing a buffer overrun of queue->tx_map_ops. Rework the code to account for the extra frag_overflow slots. This is CVE-2023-34319 / XSA-432. Fixes: ad7f402ae4f4 ("xen/netback: Ensure protocol headers don't fall in the non-linear area") Signed-off-by: Ross Lagerwall Reviewed-by: Paul Durrant Reviewed-by: Wei Liu Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

x86/srso: Tie SBPB bit setting to microcode patch detection

2023-08-08T18:03:51+00:00

commit 5a15d8348881e9371afdf9f5357a135489496955 upstream. The SBPB bit in MSR_IA32_PRED_CMD is supported only after a microcode patch has been applied so set X86_FEATURE_SBPB only then. Otherwise, guests would attempt to set that bit and #GP on the MSR write. While at it, make SMT detection more robust as some guests - depending on how and what CPUID leafs their report - lead to cpu_smt_control getting set to CPU_SMT_NOT_SUPPORTED but SRSO_NO should be set for any guest incarnation where one simply cannot do SMT, for whatever reason. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Reported-by: Konrad Rzeszutek Wilk Reported-by: Salvatore Bonaccorso Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Add a forgotten NOENDBR annotation

2023-08-08T18:03:51+00:00

Upstream commit: 3bbbe97ad83db8d9df06daf027b0840188de625d Fix: vmlinux.o: warning: objtool: .export_symbol+0x29e40: data relocation to !ENDBR: srso_untrain_ret_alias+0x0 Reported-by: Linus Torvalds Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Fix return thunks in generated code

2023-08-08T18:03:51+00:00

Upstream commit: 238ec850b95a02dcdff3edc86781aa913549282f Set X86_FEATURE_RETHUNK when enabling the SRSO mitigation so that generated code (e.g., ftrace, static call, eBPF) generates "jmp __x86_return_thunk" instead of RET. [ bp: Add a comment. ] Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Add IBPB on VMEXIT

2023-08-08T18:03:50+00:00

Upstream commit: d893832d0e1ef41c72cdae444268c1d64a2be8ad Add the option to flush IBPB only on VMEXIT in order to protect from malicious guests but one otherwise trusts the software that runs on the hypervisor. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Add IBPB

2023-08-08T18:03:50+00:00

Upstream commit: 233d6f68b98d480a7c42ebe78c38f79d44741ca9 Add the option to mitigate using IBPB on a kernel entry. Pull in the Retbleed alternative so that the IBPB call from there can be used. Also, if Retbleed mitigation is done using IBPB, the same mitigation can and must be used here. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Add SRSO_NO support

2023-08-08T18:03:50+00:00

Upstream commit: 1b5277c0ea0b247393a9c426769fde18cff5e2f6 Add support for the CPUID flag which denotes that the CPU is not affected by SRSO. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/srso: Add IBPB_BRTYPE support

2023-08-08T18:03:50+00:00

Upstream commit: 79113e4060aba744787a81edb9014f2865193854 Add support for the synthetic CPUID flag which "if this bit is 1, it indicates that MSR 49h (PRED_CMD) bit 0 (IBPB) flushes all branch type predictions from the CPU branch predictor." This flag is there so that this capability in guests can be detected easily (otherwise one would have to track microcode revisions which is impossible for guests). It is also needed only for Zen3 and -4. The other two (Zen1 and -2) always flush branch type predictions by default. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman