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[src/trunk]: src/libexec/ld.elf_so Remove the limitation of only being able t...
details: https://anonhg.NetBSD.org/src/rev/e22f04309719
branches: trunk
changeset: 372934:e22f04309719
user: christos <christos%NetBSD.org@localhost>
date: Fri Jan 06 15:33:47 2023 +0000
description:
Remove the limitation of only being able to load binaries with 2 PT_LOAD
sections, like the kernel can. From FreeBSD.
diffstat:
libexec/ld.elf_so/map_object.c | 276 ++++++++++++++++++++++------------------
1 files changed, 154 insertions(+), 122 deletions(-)
diffs (truncated from 475 to 300 lines):
diff -r e08ee8d7646d -r e22f04309719 libexec/ld.elf_so/map_object.c
--- a/libexec/ld.elf_so/map_object.c Fri Jan 06 15:07:22 2023 +0000
+++ b/libexec/ld.elf_so/map_object.c Fri Jan 06 15:33:47 2023 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: map_object.c,v 1.62 2022/03/30 08:26:45 hannken Exp $ */
+/* $NetBSD: map_object.c,v 1.63 2023/01/06 15:33:47 christos Exp $ */
/*
* Copyright 1996 John D. Polstra.
@@ -34,7 +34,7 @@
#include <sys/cdefs.h>
#ifndef lint
-__RCSID("$NetBSD: map_object.c,v 1.62 2022/03/30 08:26:45 hannken Exp $");
+__RCSID("$NetBSD: map_object.c,v 1.63 2023/01/06 15:33:47 christos Exp $");
#endif /* not lint */
#include <errno.h>
@@ -49,7 +49,8 @@
#include "debug.h"
#include "rtld.h"
-static int protflags(int); /* Elf flags -> mmap protection */
+static int convert_prot(int); /* Elf flags -> mmap protection */
+static int convert_flags(int); /* Elf flags -> mmap flags */
#define EA_UNDEF (~(Elf_Addr)0)
@@ -69,35 +70,35 @@
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
Elf_Phdr *phtls;
#endif
- size_t phsize;
Elf_Phdr *phlimit;
- Elf_Phdr *segs[2];
+ Elf_Phdr **segs = NULL;
int nsegs;
caddr_t mapbase = MAP_FAILED;
size_t mapsize = 0;
int mapflags;
- Elf_Off base_offset;
Elf_Addr base_alignment;
Elf_Addr base_vaddr;
Elf_Addr base_vlimit;
Elf_Addr text_vlimit;
- int text_flags;
+ Elf_Addr text_end;
void *base_addr;
Elf_Off data_offset;
Elf_Addr data_vaddr;
Elf_Addr data_vlimit;
int data_flags;
+ int data_prot;
caddr_t data_addr;
+ Elf_Addr bss_vaddr;
+ Elf_Addr bss_vlimit;
+ caddr_t bss_addr;
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
Elf_Addr tls_vaddr = 0; /* Noise GCC */
#endif
Elf_Addr phdr_vaddr;
- size_t phdr_memsz;
- caddr_t gap_addr;
- size_t gap_size;
int i;
#ifdef RTLD_LOADER
Elf_Addr clear_vaddr;
+ caddr_t clear_page;
caddr_t clear_addr;
size_t nclear;
#endif
@@ -105,6 +106,9 @@
Elf_Addr relro_page;
size_t relro_size;
#endif
+#ifdef notyet
+ int stack_flags;
+#endif
if (sb != NULL && sb->st_size < (off_t)sizeof (Elf_Ehdr)) {
_rtld_error("%s: not ELF file (too short)", path);
@@ -124,34 +128,34 @@
obj->ehdr = ehdr;
if (ehdr == MAP_FAILED) {
_rtld_error("%s: read error: %s", path, xstrerror(errno));
- goto bad;
+ goto error;
}
/* Make sure the file is valid */
if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0) {
_rtld_error("%s: not ELF file (magic number bad)", path);
- goto bad;
+ goto error;
}
if (ehdr->e_ident[EI_CLASS] != ELFCLASS) {
_rtld_error("%s: invalid ELF class %x; expected %x", path,
ehdr->e_ident[EI_CLASS], ELFCLASS);
- goto bad;
+ goto error;
}
/* Elf_e_ident includes class */
if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
ehdr->e_version != EV_CURRENT ||
ehdr->e_ident[EI_DATA] != ELFDEFNNAME(MACHDEP_ENDIANNESS)) {
_rtld_error("%s: unsupported file version", path);
- goto bad;
+ goto error;
}
if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
_rtld_error("%s: unsupported file type", path);
- goto bad;
+ goto error;
}
switch (ehdr->e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
_rtld_error("%s: unsupported machine", path);
- goto bad;
+ goto error;
}
/*
@@ -173,16 +177,22 @@
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
phtls = NULL;
#endif
- phsize = ehdr->e_phnum * sizeof(phdr[0]);
obj->phdr = NULL;
#ifdef GNU_RELRO
relro_page = 0;
relro_size = 0;
#endif
phdr_vaddr = EA_UNDEF;
- phdr_memsz = 0;
phlimit = phdr + ehdr->e_phnum;
- nsegs = 0;
+ segs = xmalloc(sizeof(segs[0]) * ehdr->e_phnum);
+ if (segs == NULL) {
+ _rtld_error("No memory for segs");
+ goto error;
+ }
+#ifdef notyet
+ stack_flags = PF_R | PF_W;
+#endif
+ nsegs = -1;
while (phdr < phlimit) {
switch (phdr->p_type) {
case PT_INTERP:
@@ -191,21 +201,37 @@
break;
case PT_LOAD:
- if (nsegs < 2)
- segs[nsegs] = phdr;
- ++nsegs;
+ segs[++nsegs] = phdr;
+ if ((segs[nsegs]->p_align & (_rtld_pagesz - 1)) != 0) {
+ _rtld_error(
+ "%s: PT_LOAD segment %d not page-aligned",
+ path, nsegs);
+ goto error;
+ }
+ if ((segs[nsegs]->p_flags & PF_X) == PF_X) {
+ text_end = MAX(text_end,
+ round_up(segs[nsegs]->p_vaddr +
+ segs[nsegs]->p_memsz));
+ }
- dbg(("%s: %s %p phsize %" PRImemsz, obj->path, "PT_LOAD",
+ dbg(("%s: %s %p phsize %" PRImemsz, obj->path,
+ "PT_LOAD",
(void *)(uintptr_t)phdr->p_vaddr, phdr->p_memsz));
break;
case PT_PHDR:
phdr_vaddr = phdr->p_vaddr;
- phdr_memsz = phdr->p_memsz;
- dbg(("%s: %s %p phsize %" PRImemsz, obj->path, "PT_PHDR",
+ dbg(("%s: %s %p phsize %" PRImemsz, obj->path,
+ "PT_PHDR",
(void *)(uintptr_t)phdr->p_vaddr, phdr->p_memsz));
break;
+#ifdef notyet
+ case PT_GNU_STACK:
+ stack_flags = phdr->p_flags;
+ break;
+#endif
+
#ifdef GNU_RELRO
case PT_GNU_RELRO:
relro_page = phdr->p_vaddr;
@@ -215,7 +241,8 @@
case PT_DYNAMIC:
obj->dynamic = (void *)(uintptr_t)phdr->p_vaddr;
- dbg(("%s: %s %p phsize %" PRImemsz, obj->path, "PT_DYNAMIC",
+ dbg(("%s: %s %p phsize %" PRImemsz, obj->path,
+ "PT_DYNAMIC",
(void *)(uintptr_t)phdr->p_vaddr, phdr->p_memsz));
break;
@@ -240,12 +267,7 @@
obj->entry = (void *)(uintptr_t)ehdr->e_entry;
if (!obj->dynamic) {
_rtld_error("%s: not dynamically linked", path);
- goto bad;
- }
- if (nsegs != 2) {
- _rtld_error("%s: wrong number of segments (%d != 2)", path,
- nsegs);
- goto bad;
+ goto error;
}
/*
@@ -261,17 +283,15 @@
*/
base_alignment = segs[0]->p_align;
- base_offset = round_down(segs[0]->p_offset);
base_vaddr = round_down(segs[0]->p_vaddr);
- base_vlimit = round_up(segs[1]->p_vaddr + segs[1]->p_memsz);
+ base_vlimit = round_up(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz);
text_vlimit = round_up(segs[0]->p_vaddr + segs[0]->p_memsz);
- text_flags = protflags(segs[0]->p_flags);
- data_offset = round_down(segs[1]->p_offset);
- data_vaddr = round_down(segs[1]->p_vaddr);
- data_vlimit = round_up(segs[1]->p_vaddr + segs[1]->p_filesz);
- data_flags = protflags(segs[1]->p_flags);
+ data_offset = round_down(segs[nsegs]->p_offset);
+ data_vaddr = round_down(segs[nsegs]->p_vaddr);
+ data_vlimit = round_up(segs[nsegs]->p_vaddr + segs[nsegs]->p_filesz);
+ data_flags = convert_prot(segs[nsegs]->p_flags);
#ifdef RTLD_LOADER
- clear_vaddr = segs[1]->p_vaddr + segs[1]->p_filesz;
+ clear_vaddr = segs[nsegs]->p_vaddr + segs[nsegs]->p_filesz;
#endif
obj->textsize = text_vlimit - base_vaddr;
@@ -289,54 +309,15 @@
}
#endif
- obj->phdr_loaded = false;
- for (i = 0; i < nsegs; i++) {
- if (phdr_vaddr != EA_UNDEF &&
- segs[i]->p_vaddr <= phdr_vaddr &&
- segs[i]->p_memsz >= phdr_memsz) {
- obj->phdr_loaded = true;
- break;
- }
- if (segs[i]->p_offset <= ehdr->e_phoff &&
- segs[i]->p_memsz >= phsize) {
- phdr_vaddr = segs[i]->p_vaddr + ehdr->e_phoff;
- phdr_memsz = phsize;
- obj->phdr_loaded = true;
- break;
- }
- }
- if (obj->phdr_loaded) {
- obj->phdr = (void *)(uintptr_t)phdr_vaddr;
- obj->phsize = phdr_memsz;
- } else {
- Elf_Phdr *buf;
- buf = xmalloc(phsize);
- if (buf == NULL) {
- _rtld_error("%s: cannot allocate program header", path);
- goto bad;
- }
- memcpy(buf, phdr, phsize);
- obj->phdr = buf;
- obj->phsize = phsize;
- }
- dbg(("%s: phdr %p phsize %zu (%s)", obj->path, obj->phdr, obj->phsize,
- obj->phdr_loaded ? "loaded" : "allocated"));
-
- /* Unmap header if it overlaps the first load section. */
- if (base_offset < _rtld_pagesz) {
- munmap(ehdr, _rtld_pagesz);
- obj->ehdr = MAP_FAILED;
- }
-
/*
* Calculate log2 of the base section alignment.
*/
- mapflags = 0;
+ mapflags = MAP_PRIVATE | MAP_ANON;
if (base_alignment > _rtld_pagesz) {
unsigned int log2 = 0;
for (; base_alignment > 1; base_alignment >>= 1)
log2++;
- mapflags = MAP_ALIGNED(log2);
+ mapflags |= MAP_ALIGNED(log2);
}
base_addr = NULL;
@@ -347,57 +328,90 @@
}
#endif
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