Author: avg
Date: Thu Feb 27 15:22:18 2020
New Revision: 358388
URL: https://svnweb.freebsd.org/changeset/base/358388
Log:
MFC r355325: devstat_selectdevs: resize dev_select only after copying data
The resizing could be a downsizing so some data would be lost and we
could attempt to read past the end of the new memory allocation.
Sponsored by: Panzura
Modified:
stable/12/lib/libdevstat/devstat.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/lib/libdevstat/devstat.c
==============================================================================
--- stable/12/lib/libdevstat/devstat.c Thu Feb 27 15:21:05 2020
(r358387)
+++ stable/12/lib/libdevstat/devstat.c Thu Feb 27 15:22:18 2020
(r358388)
@@ -584,10 +584,10 @@ devstat_selectdevs(struct device_selection **dev_selec
* In this case, we have selected devices before, but the device
* list has changed since we last selected devices, so we need to
* either enlarge or reduce the size of the device selection list.
+ * But delay the resizing until after copying the data to old_dev_select
+ * as to not lose any data in the case of reducing the size.
*/
} else if (*num_selections != numdevs) {
- *dev_select = (struct device_selection *)reallocf(*dev_select,
- numdevs * sizeof(struct device_selection));
*select_generation = current_generation;
init_selections = 1;
/*
@@ -643,6 +643,11 @@ devstat_selectdevs(struct device_selection **dev_selec
old_num_selections = *num_selections;
bcopy(*dev_select, old_dev_select,
sizeof(struct device_selection) * *num_selections);
+ }
+
+ if (!changed && *num_selections != numdevs) {
+ *dev_select = (struct device_selection *)reallocf(*dev_select,
+ numdevs * sizeof(struct device_selection));
}
if (init_selections != 0) {
_______________________________________________
[email protected] mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "[email protected]"
