Date: Tue, 5 Feb 2019 17:52:07 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r343781 - stable/12/sys/amd64/amd64 Message-ID: <201902051752.x15Hq7Op037386@repo.freebsd.org>
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Author: kib Date: Tue Feb 5 17:52:06 2019 New Revision: 343781 URL: https://svnweb.freebsd.org/changeset/base/343781 Log: MFC r343780: amd64: clear callee-preserved registers on syscall exit. Approved by: so Security: CVE-2019-5595 Modified: stable/12/sys/amd64/amd64/exception.S Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/amd64/amd64/exception.S ============================================================================== --- stable/12/sys/amd64/amd64/exception.S Tue Feb 5 17:49:27 2019 (r343780) +++ stable/12/sys/amd64/amd64/exception.S Tue Feb 5 17:52:06 2019 (r343781) @@ -521,12 +521,14 @@ 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 cmpq $~0,PCPU(UCR3) 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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