Re: [PATCH] fs/coda: ensure the header peeked at is the same in the actual message

2017-09-26 Thread Jan Harkes
On Sat, Sep 23, 2017 at 10:35:45PM -0400, Meng Xu wrote: > Hi Jaharkes and Coda filesystem developers, > > I am resending the email on a potential race condition bug I found in the > Coda filesystem as well as the patch I propose. Please feel free to comment > whether you think this is a serious p

Re: [PATCH] fs/coda: ensure the header peeked at is the same in the actual message

2017-09-23 Thread Meng Xu
Hi Jaharkes and Coda filesystem developers, I am resending the email on a potential race condition bug I found in the Coda filesystem as well as the patch I propose. Please feel free to comment whether you think this is a serious problem and whether the patch will work. Thank you. Best Regards, M

[PATCH] fs/coda: ensure the header peeked at is the same in the actual message

2017-09-19 Thread Meng Xu
In coda_psdev_write(), the header of the buffer is fetched twice from the userspace. The first fetch is used to peek at the opcode and unique id while the second fetch copies the whole message. However, there could be inconsistency in these two fields between two fetches as buf resides in userspace