Messages in this thread Patch in this message | | | From | Jia-Ju Bai <> | Subject | [PATCH] media: venus: fix possible buffer overlow casued bad DMA value in venus_sfr_print() | Date | Sat, 30 May 2020 10:41:17 +0800 |
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The value hdev->sfr.kva is stored in DMA memory, and it is assigned to sfr, so sfr->buf_size can be modified at anytime by malicious hardware. In this case, a buffer overflow may happen when the code "sfr->data[sfr->buf_size - 1]" is executed.
To fix this possible bug, sfr->buf_size is assigned to a local variable, and then this variable is checked before being used.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- drivers/media/platform/qcom/venus/hfi_venus.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c index 0d8855014ab3..4251a9e47a1b 100644 --- a/drivers/media/platform/qcom/venus/hfi_venus.c +++ b/drivers/media/platform/qcom/venus/hfi_venus.c @@ -960,18 +960,23 @@ static void venus_sfr_print(struct venus_hfi_device *hdev) { struct device *dev = hdev->core->dev; struct hfi_sfr *sfr = hdev->sfr.kva; + u32 buf_size; void *p; if (!sfr) return; - p = memchr(sfr->data, '\0', sfr->buf_size); + buf_size = sfr->buf_size; + if (buf_size > 1) + return; + + p = memchr(sfr->data, '\0', buf_size); /* * SFR isn't guaranteed to be NULL terminated since SYS_ERROR indicates * that Venus is in the process of crashing. */ if (!p) - sfr->data[sfr->buf_size - 1] = '\0'; + sfr->data[buf_size - 1] = '\0'; dev_err_ratelimited(dev, "SFR message from FW: %s\n", sfr->data); } -- 2.17.1
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