78 lines
3.0 KiB
Diff
78 lines
3.0 KiB
Diff
From: Steven Toth <stoth@kernellabs.com>
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Date: Tue, 6 Jun 2017 09:30:27 -0300
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Subject: [media] saa7164: fix double fetch PCIe access condition
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Origin: https://git.kernel.org/linus/6fb05e0dd32e566facb96ea61a48c7488daa5ac3
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Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-8831
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Avoid a double fetch by reusing the values from the prior transfer.
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Originally reported via https://bugzilla.kernel.org/show_bug.cgi?id=195559
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Thanks to Pengfei Wang <wpengfeinudt@gmail.com> for reporting.
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Signed-off-by: Steven Toth <stoth@kernellabs.com>
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Reported-by: Pengfei Wang <wpengfeinudt@gmail.com>
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Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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---
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drivers/media/pci/saa7164/saa7164-bus.c | 13 +------------
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1 file changed, 1 insertion(+), 12 deletions(-)
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diff --git a/drivers/media/pci/saa7164/saa7164-bus.c b/drivers/media/pci/saa7164/saa7164-bus.c
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index b2ff82fa7116..ecfeac5cdbed 100644
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--- a/drivers/media/pci/saa7164/saa7164-bus.c
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+++ b/drivers/media/pci/saa7164/saa7164-bus.c
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@@ -389,11 +389,11 @@ int saa7164_bus_get(struct saa7164_dev *dev, struct tmComResInfo* msg,
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msg_tmp.size = le16_to_cpu((__force __le16)msg_tmp.size);
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msg_tmp.command = le32_to_cpu((__force __le32)msg_tmp.command);
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msg_tmp.controlselector = le16_to_cpu((__force __le16)msg_tmp.controlselector);
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+ memcpy(msg, &msg_tmp, sizeof(*msg));
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/* No need to update the read positions, because this was a peek */
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/* If the caller specifically want to peek, return */
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if (peekonly) {
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- memcpy(msg, &msg_tmp, sizeof(*msg));
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goto peekout;
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}
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@@ -438,21 +438,15 @@ int saa7164_bus_get(struct saa7164_dev *dev, struct tmComResInfo* msg,
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space_rem = bus->m_dwSizeGetRing - curr_grp;
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if (space_rem < sizeof(*msg)) {
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- /* msg wraps around the ring */
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- memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, space_rem);
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- memcpy_fromio((u8 *)msg + space_rem, bus->m_pdwGetRing,
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- sizeof(*msg) - space_rem);
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if (buf)
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memcpy_fromio(buf, bus->m_pdwGetRing + sizeof(*msg) -
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space_rem, buf_size);
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} else if (space_rem == sizeof(*msg)) {
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- memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
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if (buf)
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memcpy_fromio(buf, bus->m_pdwGetRing, buf_size);
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} else {
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/* Additional data wraps around the ring */
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- memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
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if (buf) {
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memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp +
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sizeof(*msg), space_rem - sizeof(*msg));
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@@ -465,15 +459,10 @@ int saa7164_bus_get(struct saa7164_dev *dev, struct tmComResInfo* msg,
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} else {
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/* No wrapping */
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- memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
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if (buf)
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memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg),
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buf_size);
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}
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- /* Convert from little endian to CPU */
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- msg->size = le16_to_cpu((__force __le16)msg->size);
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- msg->command = le32_to_cpu((__force __le32)msg->command);
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- msg->controlselector = le16_to_cpu((__force __le16)msg->controlselector);
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/* Update the read positions, adjusting the ring */
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saa7164_writel(bus->m_dwGetReadPos, new_grp);
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--
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2.11.0
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