From db29073fc7aec71a40dabfc722a96ea9f3280907 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 crash if an expected string is not found

Clean up a bunch of cases where we could have strstr() fail and lead to
us dereferencing NULL.

We'll still leak memory in some cases (loops don't clean up allocations
from earlier iterations if a later iteration fails) but at least we're
not crashing.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
---
 grub-core/disk/lvm.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/grub-core/disk/lvm.c b/grub-core/disk/lvm.c
index 8e560f3..bd5ae87 100644
--- a/grub-core/disk/lvm.c
+++ b/grub-core/disk/lvm.c
@@ -539,7 +539,16 @@ grub_lvm_detect (grub_disk_t disk,
 			}
 
 		      if (seg->node_count != 1)
-			seg->stripe_size = grub_lvm_getvalue (&p, "stripe_size = ");
+			{
+			  seg->stripe_size = grub_lvm_getvalue (&p, "stripe_size = ");
+			  if (p == NULL)
+			    {
+#ifdef GRUB_UTIL
+			      grub_util_info ("unknown stripe_size");
+#endif
+			      goto lvs_segment_fail;
+			    }
+			}
 
 		      seg->nodes = grub_calloc (seg->node_count,
 						sizeof (*stripe));
@@ -559,7 +568,7 @@ grub_lvm_detect (grub_disk_t disk,
 			{
 			  p = grub_strchr (p, '"');
 			  if (p == NULL)
-			    continue;
+			    goto lvs_segment_fail2;
 			  q = ++p;
 			  while (*q != '"')
 			    q++;
@@ -578,7 +587,10 @@ grub_lvm_detect (grub_disk_t disk,
 			  stripe->start = grub_lvm_getvalue (&p, ",")
 			    * vg->extent_size;
 			  if (p == NULL)
-			    continue;
+			    {
+			      grub_free (stripe->name);
+			      goto lvs_segment_fail2;
+			    }
 
 			  stripe++;
 			}
@@ -615,7 +627,7 @@ grub_lvm_detect (grub_disk_t disk,
 
 			  p = grub_strchr (p, '"');
 			  if (p == NULL)
-			    continue;
+			    goto lvs_segment_fail2;
 			  q = ++p;
 			  while (*q != '"')
 			    q++;
@@ -703,7 +715,7 @@ grub_lvm_detect (grub_disk_t disk,
 			  p = p ? grub_strchr (p + 1, '"') : 0;
 			  p = p ? grub_strchr (p + 1, '"') : 0;
 			  if (p == NULL)
-			    continue;
+			    goto lvs_segment_fail2;
 			  q = ++p;
 			  while (*q != '"')
 			    q++;
-- 
2.14.2