Messages in this thread | | | Subject | Re: [PATCH] firewire: nosy: don't read packets bigger than requested | From | Randy Dunlap <> | Date | Mon, 3 Sep 2018 08:58:44 -0700 |
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On 09/03/2018 08:55 AM, Jann Horn wrote: > On Fri, Jul 6, 2018 at 5:16 PM Jann Horn <jannh@google.com> wrote: >> In general, accessing userspace memory beyond the length of the supplied >> buffer in VFS read/write handlers can lead to both kernel memory corruption >> (via kernel_read()/kernel_write(), which can e.g. be triggered via >> sys_splice()) and privilege escalation inside userspace. >> >> Fixes: 286468210d83 ("firewire: new driver: nosy - IEEE 1394 traffic sniffer") >> Signed-off-by: Jann Horn <jannh@google.com> >> --- >> No CC stable because this device shouldn't be available to unprivileged >> code by default and should be pretty rare. >> >> drivers/firewire/nosy.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c >> index a128dd1126ae..732075fc312e 100644 >> --- a/drivers/firewire/nosy.c >> +++ b/drivers/firewire/nosy.c >> @@ -161,11 +161,12 @@ packet_buffer_get(struct client *client, char __user *data, size_t user_length) >> if (atomic_read(&buffer->size) == 0) >> return -ENODEV; >> >> - /* FIXME: Check length <= user_length. */ >> - >> end = buffer->data + buffer->capacity; >> length = buffer->head->length; >> >> + if (length > user_length) >> + return -EINVAL; >> + >> if (&buffer->head->data[length] < end) { >> if (copy_to_user(data, buffer->head->data, length)) >> return -EFAULT; > > Ping. I sent this about two months ago, I haven't received a reply, > and from what I can tell, it hasn't landed in any tree so far... >
:( I have that same problem with some Firewire documentation patches. I plan to ask someone else to merge my patches.
-- ~Randy
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