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authorH. Peter Anvin <hpa@linux.intel.com>2011-04-05 14:24:07 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2011-04-05 14:24:07 -0700
commit3c123fd0201e0421386aefa02a362ca2a1f860e5 (patch)
treeb923859c5afb9f9b19b9718e9e365794b0784997 /libinstaller
parentb5f98decd092f6358043ff57e18383268b12c1f9 (diff)
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installer: Update and correct generate_extents()
1. Make sure extents are strictly less than 64K in size 2. Make sure extents do not cross 64K boundaries Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'libinstaller')
-rw-r--r--libinstaller/syslxmod.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/libinstaller/syslxmod.c b/libinstaller/syslxmod.c
index a68f19fb..8847b736 100644
--- a/libinstaller/syslxmod.c
+++ b/libinstaller/syslxmod.c
@@ -33,26 +33,29 @@
static void generate_extents(struct syslinux_extent *ex, int nptrs,
const sector_t *sectp, int nsect)
{
- uint32_t addr = 0x7c00 + 2*SECTOR_SIZE;
+ uint32_t addr = 0x8000; /* ldlinux.sys starts loading here */
uint32_t base;
sector_t sect, lba;
unsigned int len;
- len = lba = base = 0;
+ base = addr;
+ len = lba = 0;
memset(ex, 0, nptrs * sizeof *ex);
while (nsect) {
sect = *sectp++;
- if (len && sect == lba + len &&
- ((addr ^ (base + len * SECTOR_SIZE)) & 0xffff0000) == 0) {
- /* We can add to the current extent */
- len++;
- goto next;
- }
-
if (len) {
+ uint32_t xbytes = (len + 1) * SECTOR_SIZE;
+
+ if (sect == lba + len && xbytes < 65536 &&
+ ((addr ^ (base + xbytes - 1)) & 0xffff0000) == 0) {
+ /* We can add to the current extent */
+ len++;
+ goto next;
+ }
+
set_64_sl(&ex->lba, lba);
set_16_sl(&ex->len, len);
ex++;