Tegra is a 32 bit arch. On 32 bit systems then size_t is 32 bits so
"total" will never be higher than UINT_MAX because of integer overflows.
We need cast to u64 first before doing the math.
Also the addition earlier:
unsigned int num_unpins = num_cmdbufs + num_relocs;
That can overflow as well, but I think it's still safe because we check
both "num_cmdbufs" and "num_relocs" again in this test.
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
This is something I spotted in code review. I can't actually compile
this code. I assume this overflow test has security implications.
diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index cc80766..18a47f9 100644
--- a/drivers/gpu/host1x/job.c
+++ b/drivers/gpu/host1x/job.c
@@ -42,12 +42,12 @@ struct host1x_job *host1x_job_alloc(struct host1x_channel *ch,
/* Check that we're not going to overflow */
total = sizeof(struct host1x_job) +
- num_relocs * sizeof(struct host1x_reloc) +
- num_unpins * sizeof(struct host1x_job_unpin_data) +
- num_waitchks * sizeof(struct host1x_waitchk) +
- num_cmdbufs * sizeof(struct host1x_job_gather) +
- num_unpins * sizeof(dma_addr_t) +
- num_unpins * sizeof(u32 *);
+ (u64)num_relocs * sizeof(struct host1x_reloc) +
+ (u64)num_unpins * sizeof(struct host1x_job_unpin_data) +
+ (u64)num_waitchks * sizeof(struct host1x_waitchk) +
+ (u64)num_cmdbufs * sizeof(struct host1x_job_gather) +
+ (u64)num_unpins * sizeof(dma_addr_t) +
+ (u64)num_unpins * sizeof(u32 *);
if (total > ULONG_MAX)
return NULL;
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