CVE-2016-5412 powerpc: kvm: Infinite loop in HV mode (rhbz 1349916 1361040)

This commit is contained in:
Josh Boyer 2016-07-28 09:15:56 -04:00
parent fa6164d56e
commit 7178b87593
3 changed files with 580 additions and 0 deletions

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@ -637,6 +637,10 @@ Patch839: Revert-ALSA-hda-remove-controller-dependency-on-i915.patch
#CVE-2016-6136 rhbz 1353533 1353534
Patch841: audit-fix-a-double-fetch-in-audit_log_single_execve_arg.patch
#CVE-2016-5412 rhbz 1349916 1361040
Patch842: kvm-ppc-Book3S-HV-Pull-out-TM-state-save.patch
Patch843: kvm-ppc-Book3S-HV-Save-restore-TM-state.patch
# END OF PATCH DEFINITIONS
%endif
@ -2171,6 +2175,9 @@ fi
#
#
%changelog
* Thu Jul 28 2016 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2016-5412 powerpc: kvm: Infinite loop in HV mode (rhbz 1349916 1361040)
* Thu Jul 28 2016 Peter Robinson <pbrobinson@fedoraproject.org> 4.8.0-0.rc0.git1.1
- Filter nvme rdma modules to extras
- Fix IP Wireless driver filtering (rhbz 1356043) thanks lkundrak

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@ -0,0 +1,506 @@
Subject: [PATCH 1/2] KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures
From: Paul Mackerras <paulus@ozlabs.org>
Date: 2016-07-28 6:11:18
This moves the transactional memory state save and restore sequences
out of the guest entry/exit paths into separate procedures. This is
so that these sequences can be used in going into and out of nap
in a subsequent patch.
The only code changes here are (a) saving and restore LR on the
stack, since these new procedures get called with a bl instruction,
(b) explicitly saving r1 into the PACA instead of assuming that
HSTATE_HOST_R1(r13) is already set, and (c) removing an unnecessary
and redundant setting of MSR[TM] that should have been removed by
commit 9d4d0bdd9e0a ("KVM: PPC: Book3S HV: Add transactional memory
support", 2013-09-24) but wasn't.
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 449 +++++++++++++++++---------------
1 file changed, 237 insertions(+), 212 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 0d246fc..cfa4031 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -689,112 +689,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
- b skip_tm
-END_FTR_SECTION_IFCLR(CPU_FTR_TM)
-
- /* Turn on TM/FP/VSX/VMX so we can restore them. */
- mfmsr r5
- li r6, MSR_TM >> 32
- sldi r6, r6, 32
- or r5, r5, r6
- ori r5, r5, MSR_FP
- oris r5, r5, (MSR_VEC | MSR_VSX)@h
- mtmsrd r5
-
- /*
- * The user may change these outside of a transaction, so they must
- * always be context switched.
- */
- ld r5, VCPU_TFHAR(r4)
- ld r6, VCPU_TFIAR(r4)
- ld r7, VCPU_TEXASR(r4)
- mtspr SPRN_TFHAR, r5
- mtspr SPRN_TFIAR, r6
- mtspr SPRN_TEXASR, r7
-
- ld r5, VCPU_MSR(r4)
- rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
- beq skip_tm /* TM not active in guest */
-
- /* Make sure the failure summary is set, otherwise we'll program check
- * when we trechkpt. It's possible that this might have been not set
- * on a kvmppc_set_one_reg() call but we shouldn't let this crash the
- * host.
- */
- oris r7, r7, (TEXASR_FS)@h
- mtspr SPRN_TEXASR, r7
-
- /*
- * We need to load up the checkpointed state for the guest.
- * We need to do this early as it will blow away any GPRs, VSRs and
- * some SPRs.
- */
-
- mr r31, r4
- addi r3, r31, VCPU_FPRS_TM
- bl load_fp_state
- addi r3, r31, VCPU_VRS_TM
- bl load_vr_state
- mr r4, r31
- lwz r7, VCPU_VRSAVE_TM(r4)
- mtspr SPRN_VRSAVE, r7
-
- ld r5, VCPU_LR_TM(r4)
- lwz r6, VCPU_CR_TM(r4)
- ld r7, VCPU_CTR_TM(r4)
- ld r8, VCPU_AMR_TM(r4)
- ld r9, VCPU_TAR_TM(r4)
- mtlr r5
- mtcr r6
- mtctr r7
- mtspr SPRN_AMR, r8
- mtspr SPRN_TAR, r9
-
- /*
- * Load up PPR and DSCR values but don't put them in the actual SPRs
- * till the last moment to avoid running with userspace PPR and DSCR for
- * too long.
- */
- ld r29, VCPU_DSCR_TM(r4)
- ld r30, VCPU_PPR_TM(r4)
-
- std r2, PACATMSCRATCH(r13) /* Save TOC */
-
- /* Clear the MSR RI since r1, r13 are all going to be foobar. */
- li r5, 0
- mtmsrd r5, 1
-
- /* Load GPRs r0-r28 */
- reg = 0
- .rept 29
- ld reg, VCPU_GPRS_TM(reg)(r31)
- reg = reg + 1
- .endr
-
- mtspr SPRN_DSCR, r29
- mtspr SPRN_PPR, r30
-
- /* Load final GPRs */
- ld 29, VCPU_GPRS_TM(29)(r31)
- ld 30, VCPU_GPRS_TM(30)(r31)
- ld 31, VCPU_GPRS_TM(31)(r31)
-
- /* TM checkpointed state is now setup. All GPRs are now volatile. */
- TRECHKPT
-
- /* Now let's get back the state we need. */
- HMT_MEDIUM
- GET_PACA(r13)
- ld r29, HSTATE_DSCR(r13)
- mtspr SPRN_DSCR, r29
- ld r4, HSTATE_KVM_VCPU(r13)
- ld r1, HSTATE_HOST_R1(r13)
- ld r2, PACATMSCRATCH(r13)
-
- /* Set the MSR RI since we have our registers back. */
- li r5, MSR_RI
- mtmsrd r5, 1
-skip_tm:
+ bl kvmppc_restore_tm
+END_FTR_SECTION_IFSET(CPU_FTR_TM)
#endif
/* Load guest PMU registers */
@@ -875,12 +771,6 @@ BEGIN_FTR_SECTION
/* Skip next section on POWER7 */
b 8f
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
- /* Turn on TM so we can access TFHAR/TFIAR/TEXASR */
- mfmsr r8
- li r0, 1
- rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
- mtmsrd r8
-
/* Load up POWER8-specific registers */
ld r5, VCPU_IAMR(r4)
lwz r6, VCPU_PSPB(r4)
@@ -1470,106 +1360,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
- b 2f
-END_FTR_SECTION_IFCLR(CPU_FTR_TM)
- /* Turn on TM. */
- mfmsr r8
- li r0, 1
- rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
- mtmsrd r8
-
- ld r5, VCPU_MSR(r9)
- rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
- beq 1f /* TM not active in guest. */
-
- li r3, TM_CAUSE_KVM_RESCHED
-
- /* Clear the MSR RI since r1, r13 are all going to be foobar. */
- li r5, 0
- mtmsrd r5, 1
-
- /* All GPRs are volatile at this point. */
- TRECLAIM(R3)
-
- /* Temporarily store r13 and r9 so we have some regs to play with */
- SET_SCRATCH0(r13)
- GET_PACA(r13)
- std r9, PACATMSCRATCH(r13)
- ld r9, HSTATE_KVM_VCPU(r13)
-
- /* Get a few more GPRs free. */
- std r29, VCPU_GPRS_TM(29)(r9)
- std r30, VCPU_GPRS_TM(30)(r9)
- std r31, VCPU_GPRS_TM(31)(r9)
-
- /* Save away PPR and DSCR soon so don't run with user values. */
- mfspr r31, SPRN_PPR
- HMT_MEDIUM
- mfspr r30, SPRN_DSCR
- ld r29, HSTATE_DSCR(r13)
- mtspr SPRN_DSCR, r29
-
- /* Save all but r9, r13 & r29-r31 */
- reg = 0
- .rept 29
- .if (reg != 9) && (reg != 13)
- std reg, VCPU_GPRS_TM(reg)(r9)
- .endif
- reg = reg + 1
- .endr
- /* ... now save r13 */
- GET_SCRATCH0(r4)
- std r4, VCPU_GPRS_TM(13)(r9)
- /* ... and save r9 */
- ld r4, PACATMSCRATCH(r13)
- std r4, VCPU_GPRS_TM(9)(r9)
-
- /* Reload stack pointer and TOC. */
- ld r1, HSTATE_HOST_R1(r13)
- ld r2, PACATOC(r13)
-
- /* Set MSR RI now we have r1 and r13 back. */
- li r5, MSR_RI
- mtmsrd r5, 1
-
- /* Save away checkpinted SPRs. */
- std r31, VCPU_PPR_TM(r9)
- std r30, VCPU_DSCR_TM(r9)
- mflr r5
- mfcr r6
- mfctr r7
- mfspr r8, SPRN_AMR
- mfspr r10, SPRN_TAR
- std r5, VCPU_LR_TM(r9)
- stw r6, VCPU_CR_TM(r9)
- std r7, VCPU_CTR_TM(r9)
- std r8, VCPU_AMR_TM(r9)
- std r10, VCPU_TAR_TM(r9)
-
- /* Restore r12 as trap number. */
- lwz r12, VCPU_TRAP(r9)
-
- /* Save FP/VSX. */
- addi r3, r9, VCPU_FPRS_TM
- bl store_fp_state
- addi r3, r9, VCPU_VRS_TM
- bl store_vr_state
- mfspr r6, SPRN_VRSAVE
- stw r6, VCPU_VRSAVE_TM(r9)
-1:
- /*
- * We need to save these SPRs after the treclaim so that the software
- * error code is recorded correctly in the TEXASR. Also the user may
- * change these outside of a transaction, so they must always be
- * context switched.
- */
- mfspr r5, SPRN_TFHAR
- mfspr r6, SPRN_TFIAR
- mfspr r7, SPRN_TEXASR
- std r5, VCPU_TFHAR(r9)
- std r6, VCPU_TFIAR(r9)
- std r7, VCPU_TEXASR(r9)
-2:
+ bl kvmppc_save_tm
+END_FTR_SECTION_IFSET(CPU_FTR_TM)
#endif
/* Increment yield count if they have a VPA */
@@ -2694,6 +2486,239 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
mr r4,r31
blr
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+/*
+ * Save transactional state and TM-related registers.
+ * Called with r9 pointing to the vcpu struct.
+ * This can modify all checkpointed registers, but
+ * restores r1, r2 and r9 (vcpu pointer) before exit.
+ */
+kvmppc_save_tm:
+ mflr r0
+ std r0, PPC_LR_STKOFF(r1)
+
+ /* Turn on TM. */
+ mfmsr r8
+ li r0, 1
+ rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
+ mtmsrd r8
+
+ ld r5, VCPU_MSR(r9)
+ rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
+ beq 1f /* TM not active in guest. */
+
+ std r1, HSTATE_HOST_R1(r13)
+ li r3, TM_CAUSE_KVM_RESCHED
+
+ /* Clear the MSR RI since r1, r13 are all going to be foobar. */
+ li r5, 0
+ mtmsrd r5, 1
+
+ /* All GPRs are volatile at this point. */
+ TRECLAIM(R3)
+
+ /* Temporarily store r13 and r9 so we have some regs to play with */
+ SET_SCRATCH0(r13)
+ GET_PACA(r13)
+ std r9, PACATMSCRATCH(r13)
+ ld r9, HSTATE_KVM_VCPU(r13)
+
+ /* Get a few more GPRs free. */
+ std r29, VCPU_GPRS_TM(29)(r9)
+ std r30, VCPU_GPRS_TM(30)(r9)
+ std r31, VCPU_GPRS_TM(31)(r9)
+
+ /* Save away PPR and DSCR soon so don't run with user values. */
+ mfspr r31, SPRN_PPR
+ HMT_MEDIUM
+ mfspr r30, SPRN_DSCR
+ ld r29, HSTATE_DSCR(r13)
+ mtspr SPRN_DSCR, r29
+
+ /* Save all but r9, r13 & r29-r31 */
+ reg = 0
+ .rept 29
+ .if (reg != 9) && (reg != 13)
+ std reg, VCPU_GPRS_TM(reg)(r9)
+ .endif
+ reg = reg + 1
+ .endr
+ /* ... now save r13 */
+ GET_SCRATCH0(r4)
+ std r4, VCPU_GPRS_TM(13)(r9)
+ /* ... and save r9 */
+ ld r4, PACATMSCRATCH(r13)
+ std r4, VCPU_GPRS_TM(9)(r9)
+
+ /* Reload stack pointer and TOC. */
+ ld r1, HSTATE_HOST_R1(r13)
+ ld r2, PACATOC(r13)
+
+ /* Set MSR RI now we have r1 and r13 back. */
+ li r5, MSR_RI
+ mtmsrd r5, 1
+
+ /* Save away checkpinted SPRs. */
+ std r31, VCPU_PPR_TM(r9)
+ std r30, VCPU_DSCR_TM(r9)
+ mflr r5
+ mfcr r6
+ mfctr r7
+ mfspr r8, SPRN_AMR
+ mfspr r10, SPRN_TAR
+ std r5, VCPU_LR_TM(r9)
+ stw r6, VCPU_CR_TM(r9)
+ std r7, VCPU_CTR_TM(r9)
+ std r8, VCPU_AMR_TM(r9)
+ std r10, VCPU_TAR_TM(r9)
+
+ /* Restore r12 as trap number. */
+ lwz r12, VCPU_TRAP(r9)
+
+ /* Save FP/VSX. */
+ addi r3, r9, VCPU_FPRS_TM
+ bl store_fp_state
+ addi r3, r9, VCPU_VRS_TM
+ bl store_vr_state
+ mfspr r6, SPRN_VRSAVE
+ stw r6, VCPU_VRSAVE_TM(r9)
+1:
+ /*
+ * We need to save these SPRs after the treclaim so that the software
+ * error code is recorded correctly in the TEXASR. Also the user may
+ * change these outside of a transaction, so they must always be
+ * context switched.
+ */
+ mfspr r5, SPRN_TFHAR
+ mfspr r6, SPRN_TFIAR
+ mfspr r7, SPRN_TEXASR
+ std r5, VCPU_TFHAR(r9)
+ std r6, VCPU_TFIAR(r9)
+ std r7, VCPU_TEXASR(r9)
+
+ ld r0, PPC_LR_STKOFF(r1)
+ mtlr r0
+ blr
+
+/*
+ * Restore transactional state and TM-related registers.
+ * Called with r4 pointing to the vcpu struct.
+ * This potentially modifies all checkpointed registers.
+ * It restores r1, r2, r4 from the PACA.
+ */
+kvmppc_restore_tm:
+ mflr r0
+ std r0, PPC_LR_STKOFF(r1)
+
+ /* Turn on TM/FP/VSX/VMX so we can restore them. */
+ mfmsr r5
+ li r6, MSR_TM >> 32
+ sldi r6, r6, 32
+ or r5, r5, r6
+ ori r5, r5, MSR_FP
+ oris r5, r5, (MSR_VEC | MSR_VSX)@h
+ mtmsrd r5
+
+ /*
+ * The user may change these outside of a transaction, so they must
+ * always be context switched.
+ */
+ ld r5, VCPU_TFHAR(r4)
+ ld r6, VCPU_TFIAR(r4)
+ ld r7, VCPU_TEXASR(r4)
+ mtspr SPRN_TFHAR, r5
+ mtspr SPRN_TFIAR, r6
+ mtspr SPRN_TEXASR, r7
+
+ ld r5, VCPU_MSR(r4)
+ rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
+ beqlr /* TM not active in guest */
+ std r1, HSTATE_HOST_R1(r13)
+
+ /* Make sure the failure summary is set, otherwise we'll program check
+ * when we trechkpt. It's possible that this might have been not set
+ * on a kvmppc_set_one_reg() call but we shouldn't let this crash the
+ * host.
+ */
+ oris r7, r7, (TEXASR_FS)@h
+ mtspr SPRN_TEXASR, r7
+
+ /*
+ * We need to load up the checkpointed state for the guest.
+ * We need to do this early as it will blow away any GPRs, VSRs and
+ * some SPRs.
+ */
+
+ mr r31, r4
+ addi r3, r31, VCPU_FPRS_TM
+ bl load_fp_state
+ addi r3, r31, VCPU_VRS_TM
+ bl load_vr_state
+ mr r4, r31
+ lwz r7, VCPU_VRSAVE_TM(r4)
+ mtspr SPRN_VRSAVE, r7
+
+ ld r5, VCPU_LR_TM(r4)
+ lwz r6, VCPU_CR_TM(r4)
+ ld r7, VCPU_CTR_TM(r4)
+ ld r8, VCPU_AMR_TM(r4)
+ ld r9, VCPU_TAR_TM(r4)
+ mtlr r5
+ mtcr r6
+ mtctr r7
+ mtspr SPRN_AMR, r8
+ mtspr SPRN_TAR, r9
+
+ /*
+ * Load up PPR and DSCR values but don't put them in the actual SPRs
+ * till the last moment to avoid running with userspace PPR and DSCR for
+ * too long.
+ */
+ ld r29, VCPU_DSCR_TM(r4)
+ ld r30, VCPU_PPR_TM(r4)
+
+ std r2, PACATMSCRATCH(r13) /* Save TOC */
+
+ /* Clear the MSR RI since r1, r13 are all going to be foobar. */
+ li r5, 0
+ mtmsrd r5, 1
+
+ /* Load GPRs r0-r28 */
+ reg = 0
+ .rept 29
+ ld reg, VCPU_GPRS_TM(reg)(r31)
+ reg = reg + 1
+ .endr
+
+ mtspr SPRN_DSCR, r29
+ mtspr SPRN_PPR, r30
+
+ /* Load final GPRs */
+ ld 29, VCPU_GPRS_TM(29)(r31)
+ ld 30, VCPU_GPRS_TM(30)(r31)
+ ld 31, VCPU_GPRS_TM(31)(r31)
+
+ /* TM checkpointed state is now setup. All GPRs are now volatile. */
+ TRECHKPT
+
+ /* Now let's get back the state we need. */
+ HMT_MEDIUM
+ GET_PACA(r13)
+ ld r29, HSTATE_DSCR(r13)
+ mtspr SPRN_DSCR, r29
+ ld r4, HSTATE_KVM_VCPU(r13)
+ ld r1, HSTATE_HOST_R1(r13)
+ ld r2, PACATMSCRATCH(r13)
+
+ /* Set the MSR RI since we have our registers back. */
+ li r5, MSR_RI
+ mtmsrd r5, 1
+
+ ld r0, PPC_LR_STKOFF(r1)
+ mtlr r0
+ blr
+#endif
+
/*
* We come here if we get any exception or interrupt while we are
* executing host real mode code while in guest MMU context.
--
2.8.0.rc3

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@ -0,0 +1,67 @@
Subject: [PATCH 2/2] KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE
From: Paul Mackerras <paulus@ozlabs.org>
Date: 2016-07-28 6:11:19
It turns out that if the guest does a H_CEDE while the CPU is in
a transactional state, and the H_CEDE does a nap, and the nap
loses the architected state of the CPU (which is is allowed to do),
then we lose the checkpointed state of the virtual CPU. In addition,
the transactional-memory state recorded in the MSR gets reset back
to non-transactional, and when we try to return to the guest, we take
a TM bad thing type of program interrupt because we are trying to
transition from non-transactional to transactional with a hrfid
instruction, which is not permitted.
The result of the program interrupt occurring at that point is that
the host CPU will hang in an infinite loop with interrupts disabled.
Thus this is a denial of service vulnerability in the host which can
be triggered by any guest (and depending on the guest kernel, it can
potentially triggered by unprivileged userspace in the guest).
This vulnerability has been assigned the ID CVE-2016-5412.
To fix this, we save the TM state before napping and restore it
on exit from the nap, when handling a H_CEDE in real mode. The
case where H_CEDE exits to host virtual mode is already OK (as are
other hcalls which exit to host virtual mode) because the exit
path saves the TM state.
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index cfa4031..543124f 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2093,6 +2093,13 @@ _GLOBAL(kvmppc_h_cede) /* r3 = vcpu pointer, r11 = msr, r13 = paca */
/* save FP state */
bl kvmppc_save_fp
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+BEGIN_FTR_SECTION
+ ld r9, HSTATE_KVM_VCPU(r13)
+ bl kvmppc_save_tm
+END_FTR_SECTION_IFSET(CPU_FTR_TM)
+#endif
+
/*
* Set DEC to the smaller of DEC and HDEC, so that we wake
* no later than the end of our timeslice (HDEC interrupts
@@ -2169,6 +2176,12 @@ kvm_end_cede:
bl kvmhv_accumulate_time
#endif
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+BEGIN_FTR_SECTION
+ bl kvmppc_restore_tm
+END_FTR_SECTION_IFSET(CPU_FTR_TM)
+#endif
+
/* load up FP state */
bl kvmppc_load_fp
--
2.8.0.rc3