From: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx> As discussed here[1], if a message was smaller than the size of the message header, it could be incorrectly processed. [1] https://lore.kernel.org/driverdev-devel/2302785.6C7ODC2LYm@pc-42/ Signed-off-by: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx> --- drivers/staging/wfx/bh.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) diff --git a/drivers/staging/wfx/bh.c b/drivers/staging/wfx/bh.c index 1cbaf8bb4fa38..53ae0b5abcdd8 100644 --- a/drivers/staging/wfx/bh.c +++ b/drivers/staging/wfx/bh.c @@ -57,7 +57,6 @@ static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf) int release_count; int piggyback = 0; - WARN(read_len < 4, "corrupted read"); WARN(read_len > round_down(0xFFF, 2) * sizeof(u16), "%s: request exceed WFx capability", __func__); @@ -76,7 +75,27 @@ static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf) hif = (struct hif_msg *)skb->data; WARN(hif->encrypted & 0x1, "unsupported encryption type"); if (hif->encrypted == 0x2) { - if (wfx_sl_decode(wdev, (void *)hif)) { + if (WARN(read_len < sizeof(struct hif_sl_msg), "corrupted read")) + goto err; + computed_len = le16_to_cpu(((struct hif_sl_msg *)hif)->len); + computed_len = round_up(computed_len - sizeof(u16), 16); + computed_len += sizeof(struct hif_sl_msg); + computed_len += sizeof(struct hif_sl_tag); + } else { + if (WARN(read_len < sizeof(struct hif_msg), "corrupted read")) + goto err; + computed_len = le16_to_cpu(hif->len); + computed_len = round_up(computed_len, 2); + } + if (computed_len != read_len) { + dev_err(wdev->dev, "inconsistent message length: %zu != %zu\n", + computed_len, read_len); + print_hex_dump(KERN_INFO, "hif: ", DUMP_PREFIX_OFFSET, 16, 1, + hif, read_len, true); + goto err; + } + if (hif->encrypted == 0x2) { + if (wfx_sl_decode(wdev, (struct hif_sl_msg *)hif)) { dev_kfree_skb(skb); // If frame was a confirmation, expect trouble in next // exchange. However, it is harmless to fail to decode @@ -84,19 +103,6 @@ static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf) // piggyback is probably correct. return piggyback; } - computed_len = - round_up(le16_to_cpu(hif->len) - sizeof(hif->len), 16) + - sizeof(struct hif_sl_msg) + - sizeof(struct hif_sl_tag); - } else { - computed_len = round_up(le16_to_cpu(hif->len), 2); - } - if (computed_len != read_len) { - dev_err(wdev->dev, "inconsistent message length: %zu != %zu\n", - computed_len, read_len); - print_hex_dump(KERN_INFO, "hif: ", DUMP_PREFIX_OFFSET, 16, 1, - hif, read_len, true); - goto err; } if (!(hif->id & HIF_ID_IS_INDICATION)) { -- 2.27.0
