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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