From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Thu, 21 Jan 2021 18:35:22 +1100
Subject: [PATCH] disk/lvm: Do not overread metadata
We could reach the end of valid metadata and not realize, leading to
some buffer overreads. Check if we have reached the end and bail.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/disk/lvm.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/grub-core/disk/lvm.c b/grub-core/disk/lvm.c
index 03587e744dc..267be7b9536 100644
--- a/grub-core/disk/lvm.c
+++ b/grub-core/disk/lvm.c
@@ -314,17 +314,23 @@ error_parsing_metadata:
while (1)
{
grub_ssize_t s;
- while (grub_isspace (*p))
+ while (grub_isspace (*p) && p < mda_end)
p++;
+ if (p == mda_end)
+ goto fail4;
+
if (*p == '}')
break;
pv = grub_zalloc (sizeof (*pv));
q = p;
- while (*q != ' ')
+ while (*q != ' ' && q < mda_end)
q++;
+ if (q == mda_end)
+ goto pvs_fail_noname;
+
s = q - p;
pv->name = grub_malloc (s + 1);
grub_memcpy (pv->name, p, s);
@@ -367,6 +373,7 @@ error_parsing_metadata:
continue;
pvs_fail:
grub_free (pv->name);
+ pvs_fail_noname:
grub_free (pv);
goto fail4;
}
@@ -388,18 +395,24 @@ error_parsing_metadata:
struct grub_diskfilter_segment *seg;
int is_pvmove;
- while (grub_isspace (*p))
+ while (grub_isspace (*p) && p < mda_end)
p++;
+ if (p == mda_end)
+ goto fail4;
+
if (*p == '}')
break;
lv = grub_zalloc (sizeof (*lv));
q = p;
- while (*q != ' ')
+ while (*q != ' ' && q < mda_end)
q++;
+ if (q == mda_end)
+ goto lvs_fail;
+
s = q - p;
lv->name = grub_strndup (p, s);
if (!lv->name)
@@ -572,9 +585,12 @@ error_parsing_metadata:
if (p == NULL)
goto lvs_segment_fail2;
q = ++p;
- while (*q != '"')
+ while (q < mda_end && *q != '"')
q++;
+ if (q == mda_end)
+ goto lvs_segment_fail2;
+
s = q - p;
stripe->name = grub_malloc (s + 1);
@@ -631,9 +647,12 @@ error_parsing_metadata:
if (p == NULL)
goto lvs_segment_fail2;
q = ++p;
- while (*q != '"')
+ while (q < mda_end && *q != '"')
q++;
+ if (q == mda_end)
+ goto lvs_segment_fail2;
+
s = q - p;
lvname = grub_malloc (s + 1);