Bugzilla – Bug 1051787
VUL-0: CVE-2017-12135: xen: possibly unbounded recursion in grant table code (XSA-226)
Last modified: 2021-01-22 09:00:26 UTC
CRD: 2017-08-15 12:00 UTC
Created attachment 735051 [details] New backport for Xen 4.5. The v1 code didn't apply cleanly.
Submitted for, SUSE:SLE-11-SP1:Update:Teradata SUSE:SLE-11-SP3:Update SUSE:SLE-11-SP4:Update SUSE:SLE-12:Update SUSE:SLE-12-SP1:Update SUSE:SLE-12-SP2:Update SUSE:SLE-12-SP3:Update
Great timing :( Charles, do we *have* to redo our updates or is this something that we could ship next time?
Well, as you should have seen on the -discuss mailing list, the earlier patch caused problems on migration (certain kinds of guests simply crashed). I'd also like to note that within the Xen Project Security Team I've voiced my resistance to this approach as a whole, as we're actively breaking the hypervisor ABI this way. This concern of mine is irrespective of there not being any known users of that particular part of the interface. I.e. I rather view this as a workaround than a permanent fix. We certainly have a fixed version of the original patch meanwhile, plus a patch to at least partly deal with other issues with transitive grants (we've made some further progress yesterday, but there is still at least one unresolved issue). As to deferring the fix for this XSA - I think that's rather your call. What we should avoid though is ship with the prior version of the workaround patch.
(In reply to Jan Beulich from comment #8) Thanks, then I'll stop QA and we have to wait for a final version. I don't want to leave this unfixed.
is public now Xen Security Advisory CVE-2017-12135 / XSA-226 version 5 multiple problems with transitive grants UPDATES IN VERSION 5 ==================== Public release. ISSUE DESCRIPTION ================= 1) Code to handle copy operations on transitive grants has built in retry logic, involving a function reinvoking itself with unchanged parameters. Such use assumes that the compiler would also translate this to a so called "tail call" when generating machine code. Empirically, this is not commonly the case, allowing for theoretically unbounded nesting of such function calls. 2) The reference counting and locking discipline for transitive grants is broken. Concurrent use of the transitive grant can leak references on the transitively-referenced grant. IMPACT ====== A malicious or buggy guest may be able to crash Xen. Privilege escalation and information leaks cannot be ruled out. A malicious or buggy guest can leak references on grants it has been given, amounting to a DoS against the grantee. VULNERABLE SYSTEMS ================== All versions of Xen are vulnerable. MITIGATION ========== There is no known mitigation. CREDITS ======= This issue was discovered by Jan Beulich of SUSE. The security team would also like to thank Amazon for helping to identify that the problems with transitive grants were deeper than originally believed. RESOLUTION ========== Applying the appropriate attached patch works around this issue by disabling transitive grants by default. xsa226.patch xen-unstable, Xen 4.9.x, Xen 4.8.x xsa226-4.7.patch Xen 4.7.x xsa226-4.6.patch Xen 4.6.x xsa226-4.5.patch Xen 4.5.x $ sha256sum xsa226* b09e07aaf422ae04a4ece5e2c5b5e54036cfae5b5c632bfc6953a0cacd6f60ff xsa226.patch ca8b92b2ff58b87e8bec137a34784cbf11e2820659046df6e1d71e23bf7e7dee xsa226-4.5.patch 28c7df7edabb91fb2f1fa3fc7d6906bfae75a6e701f1cd335baafaae3e087696 xsa226-4.6.patch fffcc0a4428723e6aea391ff4f1d27326b5a3763d2308cbde64e6a786502c702 xsa226-4.7.patch $ (The .meta file is a prototype machine-readable file for describing which patches are to be applied how.)
Created attachment 737085 [details] xsa226-v6.tar.bz2 new patchset.
Xen Security Advisory CVE-2017-12135 / XSA-226 version 6 multiple problems with transitive grants UPDATES IN VERSION 6 ==================== Patches actually addressing the issue have become ready. ISSUE DESCRIPTION ================= 1) Code to handle copy operations on transitive grants has built in retry logic, involving a function reinvoking itself with unchanged parameters. Such use assumes that the compiler would also translate this to a so called "tail call" when generating machine code. Empirically, this is not commonly the case, allowing for theoretically unbounded nesting of such function calls. 2) The reference counting and locking discipline for transitive grants is broken. Concurrent use of the transitive grant can leak references on the transitively-referenced grant. IMPACT ====== A malicious or buggy guest may be able to crash Xen. Privilege escalation and information leaks cannot be ruled out. A malicious or buggy guest can leak references on grants it has been given, amounting to a DoS against the grantee. VULNERABLE SYSTEMS ================== All versions of Xen are vulnerable. MITIGATION ========== There is no known mitigation. CREDITS ======= This issue was discovered by Jan Beulich of SUSE. The security team would also like to thank Amazon for helping to identify that the problems with transitive grants were deeper than originally believed. RESOLUTION ========== Applying the appropriate attached pair of patches from the list below addresses this issue: xsa226-unstable/*.patch xen-unstable xsa226-4.9/*.patch Xen 4.9.x, Xen 4.8.x, Xen 4.7.x xsa226-4.6/*.patch Xen 4.6.x xsa226-4.5/*.patch Xen 4.5.x Note that these patches have already been applied to the respective staging trees. Alternatively, applying the appropriate attached patch from the list below works around this issue by disabling transitive grants by default: xsa226.patch xen-unstable, Xen 4.9.x, Xen 4.8.x xsa226-4.7.patch Xen 4.7.x xsa226-4.6.patch Xen 4.6.x xsa226-4.5.patch Xen 4.5.x $ sha256sum xsa226* xsa226*/* b09e07aaf422ae04a4ece5e2c5b5e54036cfae5b5c632bfc6953a0cacd6f60ff xsa226.patch 22913e87349e27bd9167d5dad2d6a449b3959516e34e78ca0ff822320c4b55da xsa226-unstable/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch 4473fd96ce4fdea5e19e0b502d65f20bd279d82473ac34ff404ce2b2cbc10be1 xsa226-unstable/0002-gnttab-fix-transitive-grant-handling.patch ca8b92b2ff58b87e8bec137a34784cbf11e2820659046df6e1d71e23bf7e7dee xsa226-4.5.patch 61096dca309f48d9e63e255a7bd76a3f5fbdd7ba1c42a3d0661f6f024b553fc7 xsa226-4.5/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch de6359e50fd2bb710469da74a596013ce275edb43d3d1c36d41452f88eee9b7d xsa226-4.5/0002-gnttab-fix-transitive-grant-handling.patch 28c7df7edabb91fb2f1fa3fc7d6906bfae75a6e701f1cd335baafaae3e087696 xsa226-4.6.patch 9f2fb6981206d39274331316cd9cd9ee73d5f610de4891f6d13181fee9bc0529 xsa226-4.6/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch e34dbba7b94942faeb3e6b7630ba06f01998e2b56be1035d76e67aa47e77457d xsa226-4.6/0002-gnttab-fix-transitive-grant-handling.patch fffcc0a4428723e6aea391ff4f1d27326b5a3763d2308cbde64e6a786502c702 xsa226-4.7.patch 624a5ba690de5de88b6fafd8429d025c013632755621f9f4e4c206e0f86419c3 xsa226-4.9/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch 01d773c5bb4cafe54daf0d14e8a3af899a7c5863513d18927c4a570a74afdb15 xsa226-4.9/0002-gnttab-fix-transitive-grant-handling.patch $
There is one more follow-up patch to this XSA posted to the mailing list. https://lists.xen.org/archives/html/xen-devel/2017-08/msg02239.html I have included this new fix with version 6.
An update workflow for this issue was started. This issue was rated as important. Please submit fixed packages until 2017-08-30. When done, reassign the bug to security-team@suse.de. https://swamp.suse.de/webswamp/wf/63847
Everything has been submitted.
Xen Security Advisory CVE-2017-12135 / XSA-226 version 7 multiple problems with transitive grants UPDATES IN VERSION 7 ==================== First patch provided in version 6 regressed 32-bit Dom0 or backend domains. The updated patch includes a fix for this. ISSUE DESCRIPTION ================= 1) Code to handle copy operations on transitive grants has built in retry logic, involving a function reinvoking itself with unchanged parameters. Such use assumes that the compiler would also translate this to a so called "tail call" when generating machine code. Empirically, this is not commonly the case, allowing for theoretically unbounded nesting of such function calls. 2) The reference counting and locking discipline for transitive grants is broken. Concurrent use of the transitive grant can leak references on the transitively-referenced grant. IMPACT ====== A malicious or buggy guest may be able to crash Xen. Privilege escalation and information leaks cannot be ruled out. A malicious or buggy guest can leak references on grants it has been given, amounting to a DoS against the grantee. VULNERABLE SYSTEMS ================== All versions of Xen are vulnerable. MITIGATION ========== There is no known mitigation. CREDITS ======= This issue was discovered by Jan Beulich of SUSE. The security team would also like to thank Amazon for helping to identify that the problems with transitive grants were deeper than originally believed. RESOLUTION ========== Applying the appropriate attached pair of patches from the list below addresses this issue: xsa226-unstable/*.patch xen-unstable xsa226-4.9/*.patch Xen 4.9.x, Xen 4.8.x, Xen 4.7.x xsa226-4.6/*.patch Xen 4.6.x xsa226-4.5/*.patch Xen 4.5.x Note that these patches have already been applied to the respective staging trees. Alternatively, applying the appropriate attached patch from the list below works around this issue by disabling transitive grants by default: xsa226.patch xen-unstable, Xen 4.9.x, Xen 4.8.x xsa226-4.7.patch Xen 4.7.x xsa226-4.6.patch Xen 4.6.x xsa226-4.5.patch Xen 4.5.x $ sha256sum xsa226* xsa226*/* b09e07aaf422ae04a4ece5e2c5b5e54036cfae5b5c632bfc6953a0cacd6f60ff xsa226.patch d999767014501d3ac62def06ccd43b97bbbf0ef7d402d3bd70ca96ac9997a14d xsa226-unstable/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch 4473fd96ce4fdea5e19e0b502d65f20bd279d82473ac34ff404ce2b2cbc10be1 xsa226-unstable/0002-gnttab-fix-transitive-grant-handling.patch ca8b92b2ff58b87e8bec137a34784cbf11e2820659046df6e1d71e23bf7e7dee xsa226-4.5.patch ca77d01172abf263b5b731f26f5e3f74b0b8c75b3e29bee3f65a9318236daba7 xsa226-4.5/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch de6359e50fd2bb710469da74a596013ce275edb43d3d1c36d41452f88eee9b7d xsa226-4.5/0002-gnttab-fix-transitive-grant-handling.patch 28c7df7edabb91fb2f1fa3fc7d6906bfae75a6e701f1cd335baafaae3e087696 xsa226-4.6.patch 0186f78e99f5f6eec913da8355e0c28946a14a6099a7219bd4e0d385fdf8c306 xsa226-4.6/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch e34dbba7b94942faeb3e6b7630ba06f01998e2b56be1035d76e67aa47e77457d xsa226-4.6/0002-gnttab-fix-transitive-grant-handling.patch fffcc0a4428723e6aea391ff4f1d27326b5a3763d2308cbde64e6a786502c702 xsa226-4.7.patch 3878c27b77ba24012599289e0e0fb1e5198b1e4efe2f87f7c46def5f335f2fd5 xsa226-4.9/0001-gnttab-dont-use-possibly-unbounded-tail-calls.patch 01d773c5bb4cafe54daf0d14e8a3af899a7c5863513d18927c4a570a74afdb15 xsa226-4.9/0002-gnttab-fix-transitive-grant-handling.patch $
Created attachment 738644 [details] xsa226-v7.tar.bz2 xsa226-v7.tar.bz2 patches attached to email
Charles, Jan? do we need resubmission compared to current state?
Only Charles can tell for sure.
(In reply to Marcus Meissner from comment #18) > Charles, Jan? > > do we need resubmission compared to current state? No. We already have this most recent fix for "32-bit Dom0 or backend domains" in the last submission. No resubmission is required.
thanks for checking!
SUSE-SU-2017:2319-1: An update that solves 6 vulnerabilities and has two fixes is now available. Category: security (important) Bug References: 1002573,1046637,1047675,1048920,1049578,1051787,1051788,1052686 CVE References: CVE-2017-10664,CVE-2017-10806,CVE-2017-11334,CVE-2017-11434,CVE-2017-12135,CVE-2017-12137 Sources used: SUSE OpenStack Cloud 6 (src): xen-4.5.5_14-22.25.1 SUSE Linux Enterprise Server for SAP 12-SP1 (src): xen-4.5.5_14-22.25.1 SUSE Linux Enterprise Server 12-SP1-LTSS (src): xen-4.5.5_14-22.25.1
SUSE-SU-2017:2326-1: An update that solves 7 vulnerabilities and has four fixes is now available. Category: security (important) Bug References: 1002573,1026236,1035231,1037840,1046637,1049578,1051787,1051788,1051789,1052686,1055695 CVE References: CVE-2016-9603,CVE-2017-10664,CVE-2017-11434,CVE-2017-12135,CVE-2017-12136,CVE-2017-12137,CVE-2017-12855 Sources used: SUSE Linux Enterprise Software Development Kit 12-SP2 (src): xen-4.7.3_03-43.9.1 SUSE Linux Enterprise Server 12-SP2 (src): xen-4.7.3_03-43.9.1 SUSE Linux Enterprise Desktop 12-SP2 (src): xen-4.7.3_03-43.9.1 SUSE Container as a Service Platform ALL (src): xen-4.7.3_03-43.9.1
SUSE-SU-2017:2327-1: An update that solves 6 vulnerabilities and has 5 fixes is now available. Category: security (important) Bug References: 1002573,1026236,1027519,1035231,1046637,1049578,1051787,1051788,1051789,1052686,1055695 CVE References: CVE-2017-10664,CVE-2017-11434,CVE-2017-12135,CVE-2017-12136,CVE-2017-12137,CVE-2017-12855 Sources used: SUSE Linux Enterprise Software Development Kit 12-SP3 (src): xen-4.9.0_11-3.9.1 SUSE Linux Enterprise Desktop 12-SP3 (src): xen-4.9.0_11-3.9.1
SUSE-SU-2017:2339-1: An update that fixes 6 vulnerabilities is now available. Category: security (important) Bug References: 1046637,1048920,1049578,1051787,1051788,1052686 CVE References: CVE-2017-10664,CVE-2017-11334,CVE-2017-11434,CVE-2017-12135,CVE-2017-12137,CVE-2017-12855 Sources used: SUSE Linux Enterprise Server 11-SP3-LTSS (src): xen-4.2.5_21-45.5.1 SUSE Linux Enterprise Point of Sale 11-SP3 (src): xen-4.2.5_21-45.5.1 SUSE Linux Enterprise Debuginfo 11-SP3 (src): xen-4.2.5_21-45.5.1
openSUSE-SU-2017:2394-1: An update that solves 6 vulnerabilities and has 5 fixes is now available. Category: security (important) Bug References: 1002573,1026236,1027519,1035231,1046637,1049578,1051787,1051788,1051789,1052686,1055695 CVE References: CVE-2017-10664,CVE-2017-11434,CVE-2017-12135,CVE-2017-12136,CVE-2017-12137,CVE-2017-12855 Sources used: openSUSE Leap 42.3 (src): xen-4.9.0_11-4.1
openSUSE-SU-2017:2398-1: An update that solves 7 vulnerabilities and has four fixes is now available. Category: security (important) Bug References: 1002573,1026236,1035231,1037840,1046637,1049578,1051787,1051788,1051789,1052686,1055695 CVE References: CVE-2016-9603,CVE-2017-10664,CVE-2017-11434,CVE-2017-12135,CVE-2017-12136,CVE-2017-12137,CVE-2017-12855 Sources used: openSUSE Leap 42.2 (src): xen-4.7.3_03-11.12.1
SUSE-SU-2017:2450-1: An update that solves 10 vulnerabilities and has three fixes is now available. Category: security (important) Bug References: 1027519,1032598,1037413,1046637,1047675,1048920,1049578,1051787,1051788,1052686,1056278,1056281,1056282 CVE References: CVE-2017-10664,CVE-2017-10806,CVE-2017-11334,CVE-2017-11434,CVE-2017-12135,CVE-2017-12137,CVE-2017-12855,CVE-2017-14316,CVE-2017-14317,CVE-2017-14319 Sources used: SUSE Linux Enterprise Software Development Kit 11-SP4 (src): xen-4.4.4_22-61.9.2 SUSE Linux Enterprise Server 11-SP4 (src): xen-4.4.4_22-61.9.2 SUSE Linux Enterprise Debuginfo 11-SP4 (src): xen-4.4.4_22-61.9.2
SUSE-SU-2017:2541-1: An update that solves 10 vulnerabilities and has four fixes is now available. Category: security (important) Bug References: 1002573,1027519,1032598,1037413,1046637,1047675,1048920,1049578,1051787,1051788,1052686,1056278,1056281,1056282 CVE References: CVE-2017-10664,CVE-2017-10806,CVE-2017-11334,CVE-2017-11434,CVE-2017-12135,CVE-2017-12137,CVE-2017-12855,CVE-2017-14316,CVE-2017-14317,CVE-2017-14319 Sources used: SUSE Linux Enterprise Server for SAP 12 (src): xen-4.4.4_22-22.51.2 SUSE Linux Enterprise Server 12-LTSS (src): xen-4.4.4_22-22.51.2
released
SUSE-SU-2017:2327-2: An update that solves 6 vulnerabilities and has 5 fixes is now available. Category: security (important) Bug References: 1002573,1026236,1027519,1035231,1046637,1049578,1051787,1051788,1051789,1052686,1055695 CVE References: CVE-2017-10664,CVE-2017-11434,CVE-2017-12135,CVE-2017-12136,CVE-2017-12137,CVE-2017-12855 Sources used: SUSE Linux Enterprise Server 12-SP3 (src): xen-4.9.0_11-3.9.1