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[PATCH v1 2/2] backup_ptes: fix leak on realloc failure
- To: <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Edwin Török <edvin.torok@xxxxxxxxxx>
- Date: Fri, 24 Feb 2023 13:36:46 +0000
- Authentication-results: esa3.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none
- Cc: Edwin Török <edwin.torok@xxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>
- Delivery-date: Fri, 24 Feb 2023 13:37:00 +0000
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From: Edwin Török <edwin.torok@xxxxxxxxx>
>From `man 2 realloc`:
`If realloc() fails, the original block is left untouched; it is not freed or
moved.`
Found using GCC -fanalyzer:
```
| 184 | backup->entries = realloc(backup->entries,
| | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| | | | |
| | | | (91) when ‘realloc’ fails
| | | (92) ‘old_ptes.entries’ leaks here; was
allocated at (44)
| | (90) ...to here
```
Signed-off-by: Edwin Török <edwin.torok@xxxxxxxxx>
---
tools/libs/guest/xg_offline_page.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/tools/libs/guest/xg_offline_page.c
b/tools/libs/guest/xg_offline_page.c
index c594fdba41..a8bcea768b 100644
--- a/tools/libs/guest/xg_offline_page.c
+++ b/tools/libs/guest/xg_offline_page.c
@@ -181,10 +181,13 @@ static int backup_ptes(xen_pfn_t table_mfn, int offset,
if (backup->max == backup->cur)
{
- backup->entries = realloc(backup->entries,
+ void* orig = backup->entries;
+ backup->entries = realloc(orig,
backup->max * 2 * sizeof(struct pte_backup_entry));
- if (backup->entries == NULL)
+ if (backup->entries == NULL) {
+ free(orig);
return -1;
+ }
else
backup->max *= 2;
}
--
2.39.1
|