2020-12-25 20:22:28

by Jim Cromie

[permalink] [raw]
Subject: [RFC PATCH v2 01/19] dyndbg: fix use before null check

In commit a2d375eda771 ("dyndbg: refine export, rename to
dynamic_debug_exec_queries()"), a string is copied before checking it
isn't NULL. Fix this, report a usage/interface error, and return the
proper error code.

Fixes: a2d375eda771 ("dyndbg: refine export, rename to dynamic_debug_exec_queries()")
Cc: [email protected]
--
-v2 drop comment tweak, improve commit message

Signed-off-by: Jim Cromie <[email protected]>
---
lib/dynamic_debug.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index bd7b3aaa93c3..c70d6347afa2 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -561,9 +561,14 @@ static int ddebug_exec_queries(char *query, const char *modname)
int dynamic_debug_exec_queries(const char *query, const char *modname)
{
int rc;
- char *qry = kstrndup(query, PAGE_SIZE, GFP_KERNEL);
+ char *qry; /* writable copy of query */

- if (!query)
+ if (!query) {
+ pr_err("non-null query/command string expected\n");
+ return -EINVAL;
+ }
+ qry = kstrndup(query, PAGE_SIZE, GFP_KERNEL);
+ if (!qry)
return -ENOMEM;

rc = ddebug_exec_queries(qry, modname);
--
2.29.2