Date: Wed, 2 Feb 2022 01:13:56 GMT From: Ed Maste <emaste@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: fd1501dcf0e8 - stable/13 - sanitizers: Improve FreeBSD ASLR detection Message-ID: <202202020113.2121DuTP042494@gitrepo.freebsd.org>
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The branch stable/13 has been updated by emaste: URL: https://cgit.FreeBSD.org/src/commit/?id=fd1501dcf0e88cb2c273a3de7710ef0fbd3fca43 commit fd1501dcf0e88cb2c273a3de7710ef0fbd3fca43 Author: Ed Maste <emaste@FreeBSD.org> AuthorDate: 2022-01-18 00:00:35 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2022-02-02 01:13:30 +0000 sanitizers: Improve FreeBSD ASLR detection The kern.elf64.aslr.pie_enable and kern.elf32.aslr.pie_enable sysctls control the default setting for PIE binary address randomization, but it is possible to enable or disable ASLR on a per-process basis. Use procctl(2) to query whether ASLR is enabled. (Note that with ASLR enabled but sysctl kern.elf64.aslr.pie_enable=0 a PIE binary will in effect have randomization disabled, and be functional with msan. This is not intended as as a user-facing control though. The user can use proccontrol(1) to disable aslr for the process.) Approved by: dim Obtained from: LLVM 64de0064f315f57044294879d9ff4eacb454d45b MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D33933 (cherry picked from commit 7cafe89f9ce33effe6e471b185339d413da1ca46) --- .../lib/sanitizer_common/sanitizer_linux.cpp | 25 +++++----------------- 1 file changed, 5 insertions(+), 20 deletions(-) diff --git a/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp index 9b7d87eb85e1..09b3f31831df 100644 --- a/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp +++ b/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp @@ -80,6 +80,7 @@ #if SANITIZER_FREEBSD #include <sys/exec.h> +#include <sys/procctl.h> #include <sys/sysctl.h> #include <machine/atomic.h> extern "C" { @@ -2187,30 +2188,14 @@ void CheckASLR() { ReExec(); } #elif SANITIZER_FREEBSD - int aslr_pie; - uptr len = sizeof(aslr_pie); -#if SANITIZER_WORDSIZE == 64 - if (UNLIKELY(internal_sysctlbyname("kern.elf64.aslr.pie_enable", - &aslr_pie, &len, NULL, 0) == -1)) { + int aslr_status; + if (UNLIKELY(procctl(P_PID, 0, PROC_ASLR_STATUS, &aslr_status) == -1)) { // We're making things less 'dramatic' here since - // the OID is not necessarily guaranteed to be here + // the cmd is not necessarily guaranteed to be here // just yet regarding FreeBSD release return; } - - if (aslr_pie > 0) { - Printf("This sanitizer is not compatible with enabled ASLR " - "and binaries compiled with PIE\n"); - Die(); - } -#endif - // there might be 32 bits compat for 64 bits - if (UNLIKELY(internal_sysctlbyname("kern.elf32.aslr.pie_enable", - &aslr_pie, &len, NULL, 0) == -1)) { - return; - } - - if (aslr_pie > 0) { + if ((aslr_status & PROC_ASLR_ACTIVE) != 0) { Printf("This sanitizer is not compatible with enabled ASLR " "and binaries compiled with PIE\n"); Die();
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