[syslinux] [PATCH 6/6] chain/partiter: correct gpt header checks
Michal Soltys
soltys at ziu.info
Sun Jun 29 12:41:43 PDT 2014
In gpt header, lba_cur and lba_alt alternate depending on whether we
read primary or backup copy.
diff --git a/com32/chain/partiter.c b/com32/chain/partiter.c
index beeb1bd..d570d93 100644
--- a/com32/chain/partiter.c
+++ b/com32/chain/partiter.c
@@ -601,10 +601,15 @@ static int notsane_gpt_hdr(const struct disk_info *di, const struct disk_gpt_hea
uint64_t gpt_loff; /* offset to GPT partition list in sectors */
uint64_t gpt_lsiz; /* size of GPT partition list in bytes */
uint64_t gpt_lcnt; /* size of GPT partition in sectors */
+ uint64_t gpt_sec; /* secondary gpt header */
if (!(flags & PIF_STRICT))
return 0;
+ if (gpth->lba_alt < gpth->lba_cur)
+ gpt_sec = gpth->lba_cur;
+ else
+ gpt_sec = gpth->lba_alt;
gpt_loff = gpth->lba_table;
gpt_lsiz = (uint64_t)gpth->part_size * gpth->part_count;
gpt_lcnt = (gpt_lsiz + di->bps - 1) / di->bps;
@@ -616,10 +621,9 @@ static int notsane_gpt_hdr(const struct disk_info *di, const struct disk_gpt_hea
if (gpt_loff < 2 || !gpt_lsiz || gpt_lcnt > 255u ||
gpth->lba_first_usable > gpth->lba_last_usable ||
!sane(gpt_loff, gpt_lcnt) ||
- gpt_loff + gpt_lcnt > gpth->lba_first_usable ||
- !sane(gpth->lba_last_usable, gpt_lcnt) ||
- gpth->lba_last_usable + gpt_lcnt >= gpth->lba_alt ||
- ((flags & PIF_STRICTER) && (gpth->lba_alt >= di->lbacnt)) ||
+ (gpt_loff + gpt_lcnt > gpth->lba_first_usable && gpt_loff <= gpth->lba_last_usable) ||
+ gpt_loff + gpt_lcnt > gpt_sec ||
+ ((flags & PIF_STRICTER) && (gpt_sec >= di->lbacnt)) ||
gpth->part_size < sizeof(struct disk_gpt_part_entry))
return -1;
--
1.7.10.4
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