Date: Mon, 13 Feb 2012 10:40:14 +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-9@freebsd.org Subject: svn commit: r231579 - stable/9/libexec/rtld-elf Message-ID: <201202131040.q1DAeED6038695@svn.freebsd.org>
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Author: kib Date: Mon Feb 13 10:40:14 2012 New Revision: 231579 URL: http://svn.freebsd.org/changeset/base/231579 Log: MFC r230784: Add support for GNU RELRO. Modified: stable/9/libexec/rtld-elf/map_object.c stable/9/libexec/rtld-elf/rtld.c stable/9/libexec/rtld-elf/rtld.h Directory Properties: stable/9/libexec/rtld-elf/ (props changed) Modified: stable/9/libexec/rtld-elf/map_object.c ============================================================================== --- stable/9/libexec/rtld-elf/map_object.c Mon Feb 13 10:24:49 2012 (r231578) +++ stable/9/libexec/rtld-elf/map_object.c Mon Feb 13 10:40:14 2012 (r231579) @@ -84,6 +84,8 @@ map_object(int fd, const char *path, con Elf_Addr bss_vlimit; caddr_t bss_addr; Elf_Word stack_flags; + Elf_Addr relro_page; + size_t relro_size; hdr = get_elf_header(fd, path); if (hdr == NULL) @@ -100,6 +102,8 @@ map_object(int fd, const char *path, con nsegs = -1; phdyn = phinterp = phtls = NULL; phdr_vaddr = 0; + relro_page = 0; + relro_size = 0; segs = alloca(sizeof(segs[0]) * hdr->e_phnum); stack_flags = RTLD_DEFAULT_STACK_PF_EXEC | PF_R | PF_W; while (phdr < phlimit) { @@ -134,6 +138,11 @@ map_object(int fd, const char *path, con case PT_GNU_STACK: stack_flags = phdr->p_flags; break; + + case PT_GNU_RELRO: + relro_page = phdr->p_vaddr; + relro_size = phdr->p_memsz; + break; } ++phdr; @@ -269,6 +278,9 @@ map_object(int fd, const char *path, con obj->tlsinit = mapbase + phtls->p_vaddr; } obj->stack_flags = stack_flags; + obj->relro_page = obj->relocbase + trunc_page(relro_page); + obj->relro_size = round_page(relro_size); + return obj; } Modified: stable/9/libexec/rtld-elf/rtld.c ============================================================================== --- stable/9/libexec/rtld-elf/rtld.c Mon Feb 13 10:24:49 2012 (r231578) +++ stable/9/libexec/rtld-elf/rtld.c Mon Feb 13 10:40:14 2012 (r231579) @@ -1114,6 +1114,11 @@ digest_phdr(const Elf_Phdr *phdr, int ph case PT_GNU_STACK: obj->stack_flags = ph->p_flags; break; + + case PT_GNU_RELRO: + obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); + obj->relro_size = round_page(ph->p_memsz); + break; } } if (nsegs < 1) { @@ -2007,6 +2012,14 @@ relocate_objects(Obj_Entry *first, bool if (reloc_jmpslots(obj, lockstate) == -1) return -1; + if (obj->relro_size > 0) { + if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { + _rtld_error("%s: Cannot enforce relro protection: %s", + obj->path, strerror(errno)); + return -1; + } + } + /* * Set up the magic number and version in the Obj_Entry. These * were checked in the crt1.o from the original ElfKit, so we Modified: stable/9/libexec/rtld-elf/rtld.h ============================================================================== --- stable/9/libexec/rtld-elf/rtld.h Mon Feb 13 10:24:49 2012 (r231578) +++ stable/9/libexec/rtld-elf/rtld.h Mon Feb 13 10:40:14 2012 (r231579) @@ -168,6 +168,9 @@ typedef struct Struct_Obj_Entry { size_t tlsoffset; /* Offset of static TLS block for this module */ size_t tlsalign; /* Alignment of static TLS block */ + caddr_t relro_page; + size_t relro_size; + /* Items from the dynamic section. */ Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ const Elf_Rel *rel; /* Relocation entries */
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