Date: Sat, 24 Jun 2017 17:04:27 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r320318 - head/libexec/rtld-elf Message-ID: <201706241704.v5OH4RSu017545@repo.freebsd.org>
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Author: kib Date: Sat Jun 24 17:04:27 2017 New Revision: 320318 URL: https://svnweb.freebsd.org/changeset/base/320318 Log: Use address space guard to implement inter-segment gap. Rtld checks and use old MAP_ANON/PROT_NONE method of creating gap if running on old kernel. Reviewed by: alc, markj Tested by: pho, Qualys Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/libexec/rtld-elf/map_object.c Modified: head/libexec/rtld-elf/map_object.c ============================================================================== --- head/libexec/rtld-elf/map_object.c Sat Jun 24 17:01:11 2017 (r320317) +++ head/libexec/rtld-elf/map_object.c Sat Jun 24 17:04:27 2017 (r320318) @@ -41,6 +41,8 @@ static Elf_Ehdr *get_elf_header(int, const char *, const struct stat *); static int convert_flags(int); /* Elf flags -> mmap flags */ +int __getosreldate(void); + /* * Map a shared object into memory. The "fd" argument is a file descriptor, * which must be open on the object and positioned at its beginning. @@ -190,7 +192,8 @@ map_object(int fd, const char *path, const struct stat base_vlimit = round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz); mapsize = base_vlimit - base_vaddr; base_addr = (caddr_t) base_vaddr; - base_flags = MAP_PRIVATE | MAP_ANON | MAP_NOCORE; + base_flags = __getosreldate() >= P_OSREL_MAP_GUARD ? MAP_GUARD : + MAP_PRIVATE | MAP_ANON | MAP_NOCORE; if (npagesizes > 1 && round_page(segs[0]->p_filesz) >= pagesizes[1]) base_flags |= MAP_ALIGNED_SUPER; if (base_vaddr != 0)
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