On Sat, 2007-08-25 at 00:17 -0400, Mathieu Desnoyers wrote:
> Fix kobject uevent string handling errors
> - add warnings when add_uevent_var. Proper handling of its return values should
> really be done by the callers, but they aren't, so things currently
> fail silently.
Right, I added the checks to kobject_uevent.c now. There are still
checks missing in:
arch/powerpc/kernel/vio.c
block/genhd.c
drivers/base/class.c
drivers/base/core.c
drivers/base/platform.c
drivers/eisa/eisa-bus.c
drivers/ide/ide.c
drivers/scsi/scsi_sysfs.c
drivers/spi/spi.c
We should fix them with a separate patch, and mark add_uevent_var() as
__must_check.
> --- linux-2.6-lttng.orig/lib/kobject_uevent.c 2007-08-25 00:07:41.000000000 -0400
> +++ linux-2.6-lttng/lib/kobject_uevent.c 2007-08-25 00:12:23.000000000 -0400
> @@ -247,8 +247,12 @@ int add_uevent_var(struct kobj_uevent_en
> va_list args;
> int len;
>
> - if (env->envp_idx >= ARRAY_SIZE(env->envp))
> + if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
> + printk("add_uevent_var: too small array size %u %u\n",
> + env->envp_idx, ARRAY_SIZE(env->envp));
> + WARN_ON(1);
> return -ENOMEM;
> + }
I added a warning to the patch.
> va_start(args, format);
> len = vsnprintf(&env->buf[env->buflen],
> @@ -256,8 +260,12 @@ int add_uevent_var(struct kobj_uevent_en
> format, args);
> va_end(args);
>
> - if (len + 1 >= (sizeof(env->buf) - env->buflen))
> + if (len >= (sizeof(env->buf) - env->buflen)) {
This is already in Greg's tree.
> + printk("add_uevent_var: failed vsnprintf %d %u\n",
> + len, (sizeof(env->buf) - env->buflen));
> + WARN_ON(1);
> return -ENOMEM;
> + }
I added a warning to the patch.
> env->envp[env->envp_idx++] = &env->buf[env->buflen];
> env->buflen += len + 1;
> Index: linux-2.6-lttng/drivers/firmware/dmi-id.c
> ===================================================================
> --- linux-2.6-lttng.orig/drivers/firmware/dmi-id.c 2007-08-25 00:07:24.000000000 -0400
> +++ linux-2.6-lttng/drivers/firmware/dmi-id.c 2007-08-25 00:07:58.000000000 -0400
> @@ -152,9 +152,10 @@ static int dmi_dev_uevent(struct device
> if (add_uevent_var(env, "MODALIAS="))
> return -ENOMEM;
> len = get_modalias(&env->buf[env->buflen - 1],
> - sizeof(env->buf) - env->buflen);
> - if (len >= (sizeof(env->buf) - env->buflen))
> + sizeof(env->buf) - (env->buflen - 1));
> + if (len >= (sizeof(env->buf) - (env->buflen - 1)))
> return -ENOMEM;
> + env->buflen += len + 1;
The increment for the trailing '\0' is already done in add_uevent_var(),
so this change is not needed, I think.
Greg,
the attached file replaces the one in your patch tree. It contains the
printk warning and a few checks for return values.
Thanks,
Kay
Attachment:
driver-core-change-add_uevent_var-to-use-a-struct.patch
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