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.
Signed-off-by: Arto Merilainen <amerilainen@xxxxxxxxxx>
Signed-off-by: Terje Bergstrom <tbergstrom@xxxxxxxxxx>
---
drivers/gpu/host1x/job.c | 50 +++++++++++++++++++-----------------------------
1 file changed, 20 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index 028d2d4..cc80766 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++) {
struct host1x_reloc *reloc = &job->relocarray[i];
u32 reloc_addr = (job->reloc_addr_phys[i] +
reloc->target_offset) >> reloc->shift;
u32 *target;
/* skip all other gathers */
- if (!(reloc->cmdbuf && cmdbuf == reloc->cmdbuf)) {
- i++;
+ if (cmdbuf != reloc->cmdbuf)
continue;
- }
if (last_page != reloc->cmdbuf_offset >> PAGE_SHIFT) {
if (cmdbuf_page_addr)
@@ -257,9 +255,6 @@ static unsigned int do_relocs(struct host1x_job *job, struct host1x_bo *cmdbuf)
target = cmdbuf_page_addr + (reloc->cmdbuf_offset & ~PAGE_MASK);
*target = reloc_addr;
-
- /* mark this gather as handled */
- reloc->cmdbuf = 0;
}
if (cmdbuf_page_addr)
@@ -378,15 +373,13 @@ static int check_nonincr(struct host1x_firewall *fw)
static int validate(struct host1x_firewall *fw, struct host1x_job_gather *g)
{
- u32 *cmdbuf_base;
+ u32 *cmdbuf_base = (u32 *)fw->job->gather_copy_mapped +
+ (g->offset / sizeof(u32));
int err = 0;
if (!fw->job->is_addr_reg)
return 0;
- cmdbuf_base = host1x_bo_mmap(g->bo);
- if (!cmdbuf_base)
- return -ENOMEM;
fw->words = g->words;
fw->cmdbuf_id = g->bo;
fw->offset = 0;
@@ -453,10 +446,17 @@ out:
static inline int copy_gathers(struct host1x_job *job, struct device *dev)
{
+ struct host1x_firewall fw;
size_t size = 0;
size_t offset = 0;
int i;
+ fw.job = job;
+ fw.dev = dev;
+ fw.reloc = job->relocarray;
+ fw.num_relocs = job->num_relocs;
+ fw.class = 0;
+
for (i = 0; i < job->num_gathers; i++) {
struct host1x_job_gather *g = &job->gathers[i];
size += g->words * sizeof(u32);
@@ -477,14 +477,19 @@ static inline int copy_gathers(struct host1x_job *job, struct device *dev)
struct host1x_job_gather *g = &job->gathers[i];
void *gather;
+ /* Copy the gather */
gather = host1x_bo_mmap(g->bo);
memcpy(job->gather_copy_mapped + offset, gather + g->offset,
g->words * sizeof(u32));
host1x_bo_munmap(g->bo, gather);
+ /* Store the location in the buffer */
g->base = job->gather_copy;
g->offset = offset;
- g->bo = NULL;
+
+ /* Validate the job */
+ if (validate(&fw, g))
+ return -EINVAL;
offset += g->words * sizeof(u32);
}
@@ -497,15 +502,8 @@ 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);
- struct host1x_firewall fw;
DECLARE_BITMAP(waitchk_mask, host1x_syncpt_nb_pts(host));
- fw.job = job;
- fw.dev = dev;
- fw.reloc = job->relocarray;
- fw.num_relocs = job->num_relocs;
- fw.class = 0;
-
bitmap_zero(waitchk_mask, host1x_syncpt_nb_pts(host));
for (i = 0; i < job->num_waitchk; i++) {
u32 syncpt_id = job->waitchk[i].syncpt_id;
@@ -536,19 +534,11 @@ int host1x_job_pin(struct host1x_job *job, struct device *dev)
if (job->gathers[j].bo == g->bo)
job->gathers[j].handled = true;
- err = 0;
-
- if (IS_ENABLED(CONFIG_TEGRA_HOST1X_FIREWALL))
- err = validate(&fw, g);
-
+ err = do_relocs(job, g->bo);
if (err)
- dev_err(dev, "Job invalid (err=%d)\n", err);
-
- if (!err)
- err = do_relocs(job, g->bo);
+ break;
- if (!err)
- err = do_waitchks(job, host, g->bo);
+ err = do_waitchks(job, host, g->bo);
if (err)
break;
}
--
1.8.1.5
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