scripts/coccinelle: add error-use-after-free.cocci

Add script to find and fix trivial use-after-free of Error objects.
How to use:
spatch --sp-file scripts/coccinelle/error-use-after-free.cocci \
 --macro-file scripts/cocci-macro-file.h --in-place \
 --no-show-diff ( FILES... | --use-gitgrep . )

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200324153630.11882-2-vsementsov@virtuozzo.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Pastos in commit message and comment fixed, globbing in MAINTAINERS
expanded]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

2 files changed, 57 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 7cb53ec138..9d156d73b3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2053,6 +2053,11 @@ F: include/qemu/error-report.h
 F: qapi/error.json
 F: util/error.c
 F: util/qemu-error.c
+F: scripts/coccinelle/err-bad-newline.cocci
+F: scripts/coccinelle/error-use-after-free.cocci
+F: scripts/coccinelle/error_propagate_null.cocci
+F: scripts/coccinelle/remove_local_err.cocci
+F: scripts/coccinelle/use-error_fatal.cocci
 
 GDB stub
 M: Alex Bennée <alex.bennee@linaro.org>
diff --git a/scripts/coccinelle/error-use-after-free.cocci b/scripts/coccinelle/error-use-after-free.cocci
new file mode 100644
index 0000000000..72ae9fdebf
--- /dev/null
+++ b/scripts/coccinelle/error-use-after-free.cocci
@@ -0,0 +1,52 @@
+// Find and fix trivial use-after-free of Error objects
+//
+// Copyright (c) 2020 Virtuozzo International GmbH.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see
+// <http://www.gnu.org/licenses/>.
+//
+// How to use:
+// spatch --sp-file scripts/coccinelle/error-use-after-free.cocci \
+//  --macro-file scripts/cocci-macro-file.h --in-place \
+//  --no-show-diff ( FILES... | --use-gitgrep . )
+
+@ exists@
+identifier fn, fn2;
+expression err;
+@@
+
+ fn(...)
+ {
+     <...
+(
+     error_free(err);
++    err = NULL;
+|
+     error_report_err(err);
++    err = NULL;
+|
+     error_reportf_err(err, ...);
++    err = NULL;
+|
+     warn_report_err(err);
++    err = NULL;
+|
+     warn_reportf_err(err, ...);
++    err = NULL;
+)
+     ... when != err = NULL
+         when != exit(...)
+     fn2(..., err, ...)
+     ...>
+ }