Date: Tue, 5 Feb 2019 18:07:45 +0000 (UTC) From: Ed Maste <emaste@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-releng@freebsd.org Subject: svn commit: r343789 - releng/11.2/sys/amd64/amd64 Message-ID: <201902051807.x15I7jM6046918@repo.freebsd.org>
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Author: emaste Date: Tue Feb 5 18:07:45 2019 New Revision: 343789 URL: https://svnweb.freebsd.org/changeset/base/343789 Log: amd64: clear callee-preserved registers on syscall exit Submitted by: kib Approved by: so Security: CVE-2019-5595 Security: FreeBSD-SA-19:01.syscall Modified: releng/11.2/sys/amd64/amd64/exception.S Modified: releng/11.2/sys/amd64/amd64/exception.S ============================================================================== --- releng/11.2/sys/amd64/amd64/exception.S Tue Feb 5 18:05:05 2019 (r343788) +++ releng/11.2/sys/amd64/amd64/exception.S Tue Feb 5 18:07:45 2019 (r343789) @@ -496,12 +496,14 @@ fast_syscall_common: movq TF_RFLAGS(%rsp),%r11 /* original %rflags */ movq TF_RIP(%rsp),%rcx /* original %rip */ movq TF_RSP(%rsp),%rsp /* user stack pointer */ + xorl %r8d,%r8d /* zero the rest of GPRs */ + xorl %r10d,%r10d cmpb $0,pti je 2f movq PCPU(UCR3),%r9 movq %r9,%cr3 - xorl %r9d,%r9d -2: swapgs +2: xorl %r9d,%r9d + swapgs sysretq 3: /* AST scheduled. */
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