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grub/grub-core/loader/i386/xen_fileXX.c
Marek Marczykowski-Górecki 67580c0068 xen: Look for Xen notes in section headers too 
Mirror behaviour of ELF loader in libxc: first look for Xen notes in
PT_NOTE segment, then in SHT_NOTE section and only then fallback to
a section with __xen_guest name. This fixes loading PV kernels that
Xen note have outside of PT_NOTE. While this may be result of a buggy
linker script, loading such kernel directly works fine, so make it work
with GRUB too. Specifically, this applies to binaries built from Unikraft.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-03-19 11:38:29 +01:00

395 lines
11 KiB
C
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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2013 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/xen_file.h>
#include <grub/misc.h>
#include <xen/elfnote.h>
static grub_err_t
parse_xen_guest (grub_elf_t elf, struct grub_xen_file_info *xi,
grub_off_t off, grub_size_t sz)
{
char *buf;
char *ptr;
int has_paddr = 0;
grub_errno = GRUB_ERR_NONE;
if (grub_file_seek (elf->file, off) == (grub_off_t) -1)
return grub_errno;
buf = grub_malloc (sz);
if (!buf)
return grub_errno;
if (grub_file_read (elf->file, buf, sz) != (grub_ssize_t) sz)
{
if (grub_errno)
goto out;
grub_free (buf);
return grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
elf->file->name);
}
xi->has_xen_guest = 1;
for (ptr = buf; ptr && ptr - buf < (grub_ssize_t) sz;
ptr = grub_strchr (ptr, ','), (ptr ? ptr++ : 0))
{
if (grub_strncmp (ptr, "PAE=no,", sizeof ("PAE=no,") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386;
continue;
}
if (grub_strncmp (ptr, "PAE=yes,", sizeof ("PAE=yes,") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE;
continue;
}
if (grub_strncmp (ptr, "PAE=yes[extended-cr3],",
sizeof ("PAE=yes[extended-cr3],") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE;
xi->extended_cr3 = 1;
continue;
}
if (grub_strncmp (ptr, "PAE=bimodal,", sizeof ("PAE=bimodal,") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
continue;
}
if (grub_strncmp (ptr, "PAE=bimodal[extended-cr3],",
sizeof ("PAE=bimodal[extended-cr3],") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
xi->extended_cr3 = 1;
continue;
}
if (grub_strncmp (ptr, "PAE=yes,bimodal,", sizeof ("PAE=yes,bimodal,") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
continue;
}
if (grub_strncmp (ptr, "PAE=yes[extended-cr3],bimodal,",
sizeof ("PAE=yes[extended-cr3],bimodal,") - 1) == 0)
{
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
continue;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
xi->extended_cr3 = 1;
continue;
}
if (grub_strncmp (ptr, "VIRT_BASE=", sizeof ("VIRT_BASE=") - 1) == 0)
{
xi->virt_base = grub_strtoull (ptr + sizeof ("VIRT_BASE=") - 1, &ptr, 16);
if (grub_errno)
goto out;
continue;
}
if (grub_strncmp (ptr, "VIRT_ENTRY=", sizeof ("VIRT_ENTRY=") - 1) == 0)
{
xi->entry_point = grub_strtoull (ptr + sizeof ("VIRT_ENTRY=") - 1, &ptr, 16);
if (grub_errno)
goto out;
continue;
}
if (grub_strncmp (ptr, "HYPERCALL_PAGE=", sizeof ("HYPERCALL_PAGE=") - 1) == 0)
{
xi->hypercall_page = grub_strtoull (ptr + sizeof ("HYPERCALL_PAGE=") - 1, &ptr, 16);
xi->has_hypercall_page = 1;
if (grub_errno)
goto out;
continue;
}
if (grub_strncmp (ptr, "ELF_PADDR_OFFSET=", sizeof ("ELF_PADDR_OFFSET=") - 1) == 0)
{
xi->paddr_offset = grub_strtoull (ptr + sizeof ("ELF_PADDR_OFFSET=") - 1, &ptr, 16);
has_paddr = 1;
if (grub_errno)
goto out;
continue;
}
}
if (xi->has_hypercall_page)
xi->hypercall_page = (xi->hypercall_page << 12) + xi->virt_base;
if (!has_paddr)
xi->paddr_offset = xi->virt_base;
out:
grub_free (buf);
return grub_errno;
}
#pragma GCC diagnostic ignored "-Wcast-align"
static grub_err_t
parse_note (grub_elf_t elf, struct grub_xen_file_info *xi,
grub_off_t off, grub_size_t sz)
{
grub_uint32_t *buf;
grub_uint32_t *ptr;
if (grub_file_seek (elf->file, off) == (grub_off_t) -1)
return grub_errno;
buf = grub_malloc (sz);
if (!buf)
return grub_errno;
if (grub_file_read (elf->file, buf, sz) != (grub_ssize_t) sz)
{
if (grub_errno)
return grub_errno;
return grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
elf->file->name);
}
for (ptr = buf; ptr - buf < (grub_ssize_t) (sz / sizeof (grub_uint32_t));)
{
Elf_Nhdr *nh = (Elf_Nhdr *) ptr;
char *name;
grub_uint32_t *desc;
grub_uint32_t namesz, descsz;
ptr += sizeof (*nh) / sizeof (grub_uint32_t);
name = (char *) ptr;
namesz = grub_le_to_cpu32 (nh->n_namesz);
descsz = grub_le_to_cpu32 (nh->n_descsz);
ptr += (namesz + 3) / 4;
desc = ptr;
ptr += (grub_le_to_cpu32 (nh->n_descsz) + 3) / 4;
if ((namesz < 3) || grub_memcmp (name, "Xen", namesz == 3 ? 3 : 4) != 0)
continue;
xi->has_note = 1;
switch (nh->n_type)
{
case XEN_ELFNOTE_ENTRY:
xi->entry_point = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
break;
case XEN_ELFNOTE_HYPERCALL_PAGE:
xi->hypercall_page = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
xi->has_hypercall_page = 1;
break;
case XEN_ELFNOTE_VIRT_BASE:
xi->virt_base = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
break;
case XEN_ELFNOTE_PADDR_OFFSET:
xi->paddr_offset = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
break;
case XEN_ELFNOTE_XEN_VERSION:
grub_dprintf ("xen", "xenversion = `%s'\n", (char *) desc);
break;
case XEN_ELFNOTE_GUEST_OS:
grub_dprintf ("xen", "name = `%s'\n", (char *) desc);
break;
case XEN_ELFNOTE_GUEST_VERSION:
grub_dprintf ("xen", "version = `%s'\n", (char *) desc);
break;
case XEN_ELFNOTE_LOADER:
if (descsz < 7
|| grub_memcmp (desc, "generic", descsz == 7 ? 7 : 8) != 0)
return grub_error (GRUB_ERR_BAD_OS, "invalid loader");
break;
/* PAE */
case XEN_ELFNOTE_PAE_MODE:
grub_dprintf ("xen", "pae = `%s', %d, %d\n", (char *) desc,
xi->arch, descsz);
if (xi->arch != GRUB_XEN_FILE_I386
&& xi->arch != GRUB_XEN_FILE_I386_PAE
&& xi->arch != GRUB_XEN_FILE_I386_PAE_BIMODE)
break;
if (descsz >= 3 && grub_memcmp (desc, "yes",
descsz == 3 ? 3 : 4) == 0)
{
xi->extended_cr3 = 1;
xi->arch = GRUB_XEN_FILE_I386_PAE;
}
if (descsz >= 7 && grub_memcmp (desc, "bimodal",
descsz == 7 ? 7 : 8) == 0)
{
xi->extended_cr3 = 1;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
}
if (descsz >= 11 && grub_memcmp (desc, "yes,bimodal",
descsz == 11 ? 11 : 12) == 0)
{
xi->extended_cr3 = 1;
xi->arch = GRUB_XEN_FILE_I386_PAE_BIMODE;
}
if (descsz >= 2 && grub_memcmp (desc, "no",
descsz == 2 ? 2 : 3) == 0)
xi->arch = GRUB_XEN_FILE_I386;
break;
case XEN_ELFNOTE_INIT_P2M:
xi->p2m_base = grub_le_to_cpu_addr (*(Elf_Addr *) desc);
xi->has_p2m_base = 1;
break;
case XEN_ELFNOTE_MOD_START_PFN:
xi->unmapped_initrd = !!grub_le_to_cpu32(*(grub_uint32_t *) desc);
break;
default:
grub_dprintf ("xen", "unknown note type %d\n", nh->n_type);
break;
}
}
return GRUB_ERR_NONE;
}
grub_err_t
grub_xen_get_infoXX (grub_elf_t elf, struct grub_xen_file_info *xi)
{
Elf_Shdr *s, *s0;
grub_size_t shnum = elf->ehdr.ehdrXX.e_shnum;
grub_size_t shentsize = elf->ehdr.ehdrXX.e_shentsize;
grub_size_t shsize = shnum * shentsize;
grub_off_t stroff;
grub_err_t err;
Elf_Phdr *phdr;
xi->kern_end = 0;
xi->kern_start = ~0;
xi->entry_point = elf->ehdr.ehdrXX.e_entry;
/* FIXME: check note. */
FOR_ELF_PHDRS (elf, phdr)
{
Elf_Addr paddr;
if (phdr->p_type == PT_NOTE)
{
err = parse_note (elf, xi, phdr->p_offset, phdr->p_filesz);
if (err)
return err;
}
if (phdr->p_type != PT_LOAD)
continue;
paddr = phdr->p_paddr;
if (paddr < xi->kern_start)
xi->kern_start = paddr;
if (paddr + phdr->p_memsz > xi->kern_end)
xi->kern_end = paddr + phdr->p_memsz;
}
if (xi->has_note)
return GRUB_ERR_NONE;
if (!shnum || !shentsize)
return grub_error (GRUB_ERR_BAD_OS, "no XEN note");
s0 = grub_malloc (shsize);
if (!s0)
return grub_errno;
if (grub_file_seek (elf->file, elf->ehdr.ehdrXX.e_shoff) == (grub_off_t) -1)
{
err = grub_errno;
goto cleanup;
}
if (grub_file_read (elf->file, s0, shsize) != (grub_ssize_t) shsize)
{
if (grub_errno)
err = grub_errno;
else
err = grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
elf->file->name);
goto cleanup;
}
s = (Elf_Shdr *) ((char *) s0 + elf->ehdr.ehdrXX.e_shstrndx * shentsize);
stroff = s->sh_offset;
for (s = s0; s < (Elf_Shdr *) ((char *) s0 + shnum * shentsize);
s = (Elf_Shdr *) ((char *) s + shentsize))
{
if (s->sh_type == SHT_NOTE)
{
err = parse_note (elf, xi, s->sh_offset, s->sh_size);
if (err)
goto cleanup;
}
}
if (xi->has_note)
{
err = GRUB_ERR_NONE;
goto cleanup;
}
for (s = s0; s < (Elf_Shdr *) ((char *) s0 + shnum * shentsize);
s = (Elf_Shdr *) ((char *) s + shentsize))
{
char name[sizeof("__xen_guest")];
grub_memset (name, 0, sizeof (name));
if (grub_file_seek (elf->file, stroff + s->sh_name) == (grub_off_t) -1)
{
err = grub_errno;
goto cleanup;
}
if (grub_file_read (elf->file, name, sizeof (name)) != (grub_ssize_t) sizeof (name))
{
if (grub_errno)
{
err = grub_errno;
goto cleanup;
}
continue;
}
if (grub_memcmp (name, "__xen_guest",
sizeof("__xen_guest")) != 0)
continue;
err = parse_xen_guest (elf, xi, s->sh_offset, s->sh_size);
goto cleanup;
}
err = grub_error (GRUB_ERR_BAD_OS, "no XEN note found");
cleanup:
grub_free (s0);
return err;
}
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