[PATCH 4.9 221/240] kobject_uevent: remove warning in init_uevent_argv()

Greg Kroah-Hartman
2021-05-20T11:25:41Z

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit b4104180a2efb85f55e1ba1407885c9421970338 upstream.

syzbot can trigger the WARN() in init_uevent_argv() which isn't the
nicest as the code does properly recover and handle the error. So
change the WARN() call to pr_warn() and provide some more information on
what the buffer size that was needed.

Link: https://lore.kernel.org/r/20201107082206.GA19079@kroah.com
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: linux-kernel@vger.kernel.org
Reported-by: syzbot+92340f7b2b4789907fdb@syzkaller.appspotmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20210405094852.1348499-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
lib/kobject_uevent.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -128,12 +128,13 @@ static int kobj_usermode_filter(struct k

static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
{
+ int buffer_size = sizeof(env->buf) - env->buflen;
int len;

- len = strlcpy(&env->buf[env->buflen], subsystem,
- sizeof(env->buf) - env->buflen);
- if (len >= (sizeof(env->buf) - env->buflen)) {
- WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
+ len = strlcpy(&env->buf[env->buflen], subsystem, buffer_size);
+ if (len >= buffer_size) {
+ pr_warn("init_uevent_argv: buffer size of %d too small, needed %d\n",
+ buffer_size, len);
return -ENOMEM;
}