On 16.05.2017 10:32, Erik Faye-Lund wrote:
On Tue, May 16, 2017 at 8:56 AM, Mikko Perttunen <cyndis@xxxxxxxx> wrote:
On 14.05.2017 23:47, Dmitry Osipenko wrote:
If commands buffer claims a number of words that is higher than its BO can
fit, a kernel OOPS will be fired on the out-of-bounds BO access. This was
triggered by an opentegra Xorg driver that erroneously pushed too many
commands to the pushbuf. The CMDA commands buffer address is 4 bytes
aligned, so check the alignment as well.
Add a sanity check for the relocations in a same way.
[ 46.829393] Unable to handle kernel paging request at virtual address
f09b2000
...
[<c04a3ba4>] (host1x_job_pin) from [<c04dfcd0>]
(tegra_drm_submit+0x474/0x510)
[<c04dfcd0>] (tegra_drm_submit) from [<c04deea0>] (tegra_submit+0x50/0x6c)
[<c04deea0>] (tegra_submit) from [<c04c07c0>] (drm_ioctl+0x1e4/0x3ec)
[<c04c07c0>] (drm_ioctl) from [<c02541a0>] (do_vfs_ioctl+0x9c/0x8e4)
[<c02541a0>] (do_vfs_ioctl) from [<c0254a1c>] (SyS_ioctl+0x34/0x5c)
[<c0254a1c>] (SyS_ioctl) from [<c0107640>] (ret_fast_syscall+0x0/0x3c)
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Reviewed-by: Erik Faye-Lund <kusmabite@xxxxxxxxx>
---
drivers/gpu/drm/tegra/drm.c | 30 ++++++++++++++++++++++++++++++
drivers/gpu/drm/tegra/gem.c | 5 -----
drivers/gpu/drm/tegra/gem.h | 5 +++++
3 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 768750226452..c5844a065681 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -362,6 +362,8 @@ int tegra_drm_submit(struct tegra_drm_context
*context,
while (num_cmdbufs) {
struct drm_tegra_cmdbuf cmdbuf;
struct host1x_bo *bo;
+ struct tegra_bo *obj;
+ u64 offset;
if (copy_from_user(&cmdbuf, cmdbufs, sizeof(cmdbuf))) {
err = -EFAULT;
@@ -374,6 +376,14 @@ int tegra_drm_submit(struct tegra_drm_context
*context,
goto fail;
}
+ offset = (u64)cmdbuf.offset + (u64)cmdbuf.words *
sizeof(u32);
+ obj = host1x_to_tegra_bo(bo);
+
+ if (offset & 3 || offset > obj->gem.size) {
+ err = -EINVAL;
+ goto fail;
+ }
+
host1x_job_add_gather(job, bo, cmdbuf.words,
cmdbuf.offset);
num_cmdbufs--;
cmdbufs++;
@@ -381,11 +391,31 @@ int tegra_drm_submit(struct tegra_drm_context
*context,
/* copy and resolve relocations from submit */
while (num_relocs--) {
+ struct host1x_reloc *reloc;
+ struct tegra_bo *obj;
+
err =
host1x_reloc_copy_from_user(&job->relocarray[num_relocs],
&relocs[num_relocs],
drm,
file);
if (err < 0)
goto fail;
+
+ reloc = &job->relocarray[num_relocs];
+ obj = host1x_to_tegra_bo(reloc->cmdbuf.bo);
+
+ if (reloc->cmdbuf.offset & 3 ||
+ reloc->cmdbuf.offset > obj->gem.size) {
This could still fail if the bo's size is not divisible by 4, even with >=
comparison (we would overwrite the buffer by 1 to 3 bytes). I would do the
same as in the gather case, i.e. find out the address immediately after the
write and compare using >. Perhaps add a helper function if it makes sense.
I also don't think the "& 3" checks are needed.
The bo-size is always a multiple of PAGE_SIZE, due to the rounding in
tegra_bo_alloc_object(), so I don't think this actually can fail. But
maybe we want to future-proof this code for a potential future where
this is not the case?
Yeah, I think whether or not this might change in the future, the code
would be easier to understand with the change.
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