Messages in this thread | | | Date | Mon, 27 May 2013 09:22:15 +0300 | From | Arto Merilainen <> | Subject | Re: [PATCH 1/6] gpu: host1x: Fixes to host1x firewall |
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On 05/26/2013 01:02 PM, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Fri, May 17, 2013 at 02:49:43PM +0300, Arto Merilainen wrote: >> From: Terje Bergstrom <tbergstrom@nvidia.com> >> >> This patch adds several fixes to host1x firewall: >> - Host1x firewall does not survive if it expects a reloc, but user >> space didn't pass any relocs. Also it reset the reloc table for >> each gather, whereas they should be reset only per submit. Also >> class does not need to be reset for each class - once per submit >> is enough. >> - For INCR opcode the check was not working properly at all. >> - The firewall verified gather buffers before copying them. This >> allowed a malicious application to rewrite the buffer content by >> timing the rewrite carefully. This patch makes the buffer >> validation occur after copying the buffers. > > Can these be split into separate patches, please? It's not only always > good to split logical changes into separate patches but it also makes > reviewing a lot more pleasant. It's hard to tell from this combined > patch which changes belong together.
Sure.
> > I have a few additional comments inline. > >> diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c >> index f665d67..4f3c004 100644 >> --- a/drivers/gpu/host1x/job.c >> +++ b/drivers/gpu/host1x/job.c >> @@ -228,17 +228,15 @@ static unsigned int do_relocs(struct host1x_job *job, struct host1x_bo *cmdbuf) >> void *cmdbuf_page_addr = NULL; >> >> /* pin & patch the relocs for one gather */ >> - while (i < job->num_relocs) { >> + for (i = 0; i < job->num_relocs; ++i) { > > Nit: I prefer post-increment where possible. For consistency.
Will do.
> >> @@ -268,15 +263,15 @@ static unsigned int do_relocs(struct host1x_job *job, struct host1x_bo *cmdbuf) >> return 0; >> } >> >> -static int check_reloc(struct host1x_reloc *reloc, struct host1x_bo *cmdbuf, >> - unsigned int offset) >> +static bool check_reloc(struct host1x_reloc *reloc, struct host1x_bo *cmdbuf, >> + unsigned int offset) >> { >> offset *= sizeof(u32); >> >> - if (reloc->cmdbuf != cmdbuf || reloc->cmdbuf_offset != offset) >> - return -EINVAL; >> + if (!reloc || reloc->cmdbuf != cmdbuf || reloc->cmdbuf_offset != offset) > > Is the additional !reloc check really necessary? Looking at the callers, > they always pass in fw->relocarray, which in turn is only NULL if no > buffers are to be relocated.
Yes, the additional check is necessary exactly for that reason. The code will fail if the userspace does not deliver a relocation array and still pushes data to an address register.
However, the code *should* check that there are relocations left before even coming here so I probably just fix this differently.
> >> + return true; >> >> - return 0; >> + return false; >> } > > I wonder whether we should be changing the logic here and have the > check_reloc() function return true if the relocation is good. I find > that to be more intuitive. >
I was also thinking that earlier. Will do.
>> @@ -508,6 +502,7 @@ int host1x_job_pin(struct host1x_job *job, struct device *dev) >> int err; >> unsigned int i, j; >> struct host1x *host = dev_get_drvdata(dev->parent); >> + >> DECLARE_BITMAP(waitchk_mask, host1x_syncpt_nb_pts(host)); > > This is an unnecessary whitespace change.
Ops. Will fix.
- Arto
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