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Groups > linux.kernel > #1707744

[PATCH 4.9 35/93] [media] saa7164: fix double fetch PCIe access condition

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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Steven Toth <stoth@kernellabs.com>

commit 6fb05e0dd32e566facb96ea61a48c7488daa5ac3 upstream.

Avoid a double fetch by reusing the values from the prior transfer.

Originally reported via https://bugzilla.kernel.org/show_bug.cgi?id=195559

Thanks to Pengfei Wang <wpengfeinudt@gmail.com> for reporting.

Signed-off-by: Steven Toth <stoth@kernellabs.com>
Reported-by: Pengfei Wang <wpengfeinudt@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/pci/saa7164/saa7164-bus.c |   13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

--- a/drivers/media/pci/saa7164/saa7164-bus.c
+++ b/drivers/media/pci/saa7164/saa7164-bus.c
@@ -393,11 +393,11 @@ int saa7164_bus_get(struct saa7164_dev *
 	msg_tmp.size = le16_to_cpu((__force __le16)msg_tmp.size);
 	msg_tmp.command = le32_to_cpu((__force __le32)msg_tmp.command);
 	msg_tmp.controlselector = le16_to_cpu((__force __le16)msg_tmp.controlselector);
+	memcpy(msg, &msg_tmp, sizeof(*msg));
 
 	/* No need to update the read positions, because this was a peek */
 	/* If the caller specifically want to peek, return */
 	if (peekonly) {
-		memcpy(msg, &msg_tmp, sizeof(*msg));
 		goto peekout;
 	}
 
@@ -442,21 +442,15 @@ int saa7164_bus_get(struct saa7164_dev *
 		space_rem = bus->m_dwSizeGetRing - curr_grp;
 
 		if (space_rem < sizeof(*msg)) {
-			/* msg wraps around the ring */
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, space_rem);
-			memcpy_fromio((u8 *)msg + space_rem, bus->m_pdwGetRing,
-				sizeof(*msg) - space_rem);
 			if (buf)
 				memcpy_fromio(buf, bus->m_pdwGetRing + sizeof(*msg) -
 					space_rem, buf_size);
 
 		} else if (space_rem == sizeof(*msg)) {
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 			if (buf)
 				memcpy_fromio(buf, bus->m_pdwGetRing, buf_size);
 		} else {
 			/* Additional data wraps around the ring */
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 			if (buf) {
 				memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp +
 					sizeof(*msg), space_rem - sizeof(*msg));
@@ -469,15 +463,10 @@ int saa7164_bus_get(struct saa7164_dev *
 
 	} else {
 		/* No wrapping */
-		memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 		if (buf)
 			memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg),
 				buf_size);
 	}
-	/* Convert from little endian to CPU */
-	msg->size = le16_to_cpu((__force __le16)msg->size);
-	msg->command = le32_to_cpu((__force __le32)msg->command);
-	msg->controlselector = le16_to_cpu((__force __le16)msg->controlselector);
 
 	/* Update the read positions, adjusting the ring */
 	saa7164_writel(bus->m_dwGetReadPos, new_grp);

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[PATCH 4.9 00/93] 4.9.42-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 23/93] gpiolib: skip unwanted events, dont convert them to opposite edge Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 19/93] timers: Fix overflow in get_next_timer_interrupt Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 26/93] ARM: dts: armada-38x: Fix irq type for pca955 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 06/93] iwlwifi: dvm: prevent an out of bounds access Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 41/93] ipv4: ipv6: initialize treq->txhash in cookie_v[46]_check() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 37/93] tcp_bbr: introduce bbr_bw_to_pacing_rate() helper Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 10/93] device property: Make dev_fwnode() public Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 40/93] tcp_bbr: init pacing rate on first RTT sample Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 11/93] mmc: core: Fix access to HS400-ES devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 21/93] powerpc/64: Fix __check_irq_replay missing decrementer interrupt Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 36/93] tcp_bbr: cut pacing rate only if filled pipe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 12/93] mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 24/93] ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 20/93] powerpc/tm: Fix saving of TM SPRs in core dump Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 33/93] f2fs: sanity check checkpoint segno and blkoff Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 29/93] iscsi-target: Fix initial login PDU asynchronous socket close OOPs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 35/93] [media] saa7164: fix double fetch PCIe access condition Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 32/93] media: lirc: LIRC_GET_REC_RESOLUTION should return microseconds Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 01/93] parisc: Handle vmas whose context is not current in flush_cache_range Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 44/93] net: dsa: b53: Add missing ARL entries for BCM53125 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 08/93] NFSv4: Fix EXCHANGE_ID corrupt verifier issue Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  [PATCH 4.9 43/93] ipv6: avoid overflow of offset in ip6_find_1stfragopt Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-09 20:40 +0200
  Re: [PATCH 4.9 00/93] 4.9.42-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-08-10 02:20 +0200
  Re: [PATCH 4.9 00/93] 4.9.42-stable review Guenter Roeck <linux@roeck-us.net> - 2017-08-10 02:50 +0200
  Re: [PATCH 4.9 00/93] 4.9.42-stable review Sumit Semwal <sumit.semwal@linaro.org> - 2017-08-10 05:10 +0200

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