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xen: Fix parsing of XZ kernel.

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In case of xz, the uncompressed size is appended to xz data which confuses
our xz decompressor. Trim it.
This commit is contained in:
Vladimir Serbinenko 2017-02-07 00:47:23 +01:00
parent 8a96fc4093
commit 529818738f
1 changed files with 26 additions and 6 deletions
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32
grub-core/loader/i386/xen_file.c
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@ -20,12 +20,16 @@
#include <grub/i386/linux.h> #include <grub/i386/linux.h>
#include <grub/misc.h> #include <grub/misc.h>
#define XZ_MAGIC "\3757zXZ\0"
grub_elf_t grub_elf_t
grub_xen_file (grub_file_t file) grub_xen_file (grub_file_t file)
{ {
grub_elf_t elf; grub_elf_t elf;
struct linux_kernel_header lh; struct linux_kernel_header lh;
grub_file_t off_file; grub_file_t off_file;
grub_uint32_t payload_offset, payload_length;
grub_uint8_t magic[6];
elf = grub_elf_file (file, file->name); elf = grub_elf_file (file, file->name);
if (elf) if (elf)
@ -46,20 +50,36 @@ grub_xen_file (grub_file_t file)
return NULL; return NULL;
} }
if (lh.payload_length < 4) payload_length = lh.payload_length;
payload_offset = (lh.setup_sects + 1) * 512
+ lh.payload_offset;
if (payload_length < sizeof (magic))
{ {
grub_error (GRUB_ERR_BAD_OS, "payload too short"); grub_error (GRUB_ERR_BAD_OS, "payload too short");
return NULL; return NULL;
} }
grub_dprintf ("xen", "found bzimage payload 0x%llx-0x%llx\n", grub_dprintf ("xen", "found bzimage payload 0x%llx-0x%llx\n",
(unsigned long long) (lh.setup_sects + 1) * 512 (unsigned long long) payload_offset,
+ lh.payload_offset,
(unsigned long long) lh.payload_length); (unsigned long long) lh.payload_length);
off_file = grub_file_offset_open (file, (lh.setup_sects + 1) * 512 grub_file_seek (file, payload_offset);
+ lh.payload_offset,
lh.payload_length); if (grub_file_read (file, &magic, sizeof (magic)) != sizeof (magic))
{
if (!grub_errno)
grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
file->name);
goto fail;
}
/* Kernel suffixes xz payload with their uncompressed size.
Trim it. */
if (grub_memcmp (magic, XZ_MAGIC, sizeof (XZ_MAGIC) - 1) == 0)
payload_length -= 4;
off_file = grub_file_offset_open (file, payload_offset,
payload_length);
if (!off_file) if (!off_file)
goto fail; goto fail;