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.
+ err = -EINVAL; + goto fail; + } + + obj = host1x_to_tegra_bo(reloc->target.bo); + + if (reloc->target.offset & 3 || + reloc->target.offset > obj->gem.size) { + err = -EINVAL; + goto fail; + } } if (copy_from_user(job->waitchk, waitchks, diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c index b76d7ac75696..a0ff30c01ac1 100644 --- a/drivers/gpu/drm/tegra/gem.c +++ b/drivers/gpu/drm/tegra/gem.c @@ -20,11 +20,6 @@ #include "drm.h" #include "gem.h" -static inline struct tegra_bo *host1x_to_tegra_bo(struct host1x_bo *bo) -{ - return container_of(bo, struct tegra_bo, base); -} - static void tegra_bo_put(struct host1x_bo *bo) { struct tegra_bo *obj = host1x_to_tegra_bo(bo); diff --git a/drivers/gpu/drm/tegra/gem.h b/drivers/gpu/drm/tegra/gem.h index 6c5f12ac0087..8b32a6fd586d 100644 --- a/drivers/gpu/drm/tegra/gem.h +++ b/drivers/gpu/drm/tegra/gem.h @@ -52,6 +52,11 @@ static inline struct tegra_bo *to_tegra_bo(struct drm_gem_object *gem) return container_of(gem, struct tegra_bo, gem); } +static inline struct tegra_bo *host1x_to_tegra_bo(struct host1x_bo *bo) +{ + return container_of(bo, struct tegra_bo, base); +} + struct tegra_bo *tegra_bo_create(struct drm_device *drm, size_t size, unsigned long flags); struct tegra_bo *tegra_bo_create_with_handle(struct drm_file *file,
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