From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxx Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx Reported-by: syzbot+92340f7b2b4789907fdb@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210405094852.1348499-1-gregkh@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/kobject_uevent.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -251,12 +251,13 @@ 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; }
