[3.13.y.z extended stable] Patch "IB/ipath: Fix potential buffer overrun in sending diag packet routine" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu May 1 19:17:16 UTC 2014


This is a note to let you know that I have just added a patch titled

    IB/ipath: Fix potential buffer overrun in sending diag packet routine

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 9d3b5cd683b3b009249bf1a1db4602c36151fa8e Mon Sep 17 00:00:00 2001
From: Dennis Dalessandro <dennis.dalessandro at intel.com>
Date: Thu, 20 Feb 2014 11:02:53 -0500
Subject: IB/ipath: Fix potential buffer overrun in sending diag packet routine

commit a2cb0eb8a64adb29a99fd864013de957028f36ae upstream.

Guard against a potential buffer overrun.  The size to read from the
user is passed in, and due to the padding that needs to be taken into
account, as well as the place holder for the ICRC it is possible to
overflow the 32bit value which would cause more data to be copied from
user space than is allocated in the buffer.

Reported-by: Nico Golde <nico at ngolde.de>
Reported-by: Fabian Yamaguchi <fabs at goesec.de>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn at intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro at intel.com>
Signed-off-by: Roland Dreier <roland at purestorage.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/infiniband/hw/ipath/ipath_diag.c | 66 ++++++++++++--------------------
 1 file changed, 25 insertions(+), 41 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_diag.c b/drivers/infiniband/hw/ipath/ipath_diag.c
index 714293b..e2f9a51 100644
--- a/drivers/infiniband/hw/ipath/ipath_diag.c
+++ b/drivers/infiniband/hw/ipath/ipath_diag.c
@@ -326,7 +326,7 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 				   size_t count, loff_t *off)
 {
 	u32 __iomem *piobuf;
-	u32 plen, clen, pbufn;
+	u32 plen, pbufn, maxlen_reserve;
 	struct ipath_diag_pkt odp;
 	struct ipath_diag_xpkt dp;
 	u32 *tmpbuf = NULL;
@@ -335,51 +335,29 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 	u64 val;
 	u32 l_state, lt_state; /* LinkState, LinkTrainingState */

-	if (count < sizeof(odp)) {
-		ret = -EINVAL;
-		goto bail;
-	}

 	if (count == sizeof(dp)) {
 		if (copy_from_user(&dp, data, sizeof(dp))) {
 			ret = -EFAULT;
 			goto bail;
 		}
-	} else if (copy_from_user(&odp, data, sizeof(odp))) {
-		ret = -EFAULT;
+	} else if (count == sizeof(odp)) {
+		if (copy_from_user(&odp, data, sizeof(odp))) {
+			ret = -EFAULT;
+			goto bail;
+		}
+	} else {
+		ret = -EINVAL;
 		goto bail;
 	}

-	/*
-	 * Due to padding/alignment issues (lessened with new struct)
-	 * the old and new structs are the same length. We need to
-	 * disambiguate them, which we can do because odp.len has never
-	 * been less than the total of LRH+BTH+DETH so far, while
-	 * dp.unit (same offset) unit is unlikely to get that high.
-	 * Similarly, dp.data, the pointer to user at the same offset
-	 * as odp.unit, is almost certainly at least one (512byte)page
-	 * "above" NULL. The if-block below can be omitted if compatibility
-	 * between a new driver and older diagnostic code is unimportant.
-	 * compatibility the other direction (new diags, old driver) is
-	 * handled in the diagnostic code, with a warning.
-	 */
-	if (dp.unit >= 20 && dp.data < 512) {
-		/* very probable version mismatch. Fix it up */
-		memcpy(&odp, &dp, sizeof(odp));
-		/* We got a legacy dp, copy elements to dp */
-		dp.unit = odp.unit;
-		dp.data = odp.data;
-		dp.len = odp.len;
-		dp.pbc_wd = 0; /* Indicate we need to compute PBC wd */
-	}
-
 	/* send count must be an exact number of dwords */
 	if (dp.len & 3) {
 		ret = -EINVAL;
 		goto bail;
 	}

-	clen = dp.len >> 2;
+	plen = dp.len >> 2;

 	dd = ipath_lookup(dp.unit);
 	if (!dd || !(dd->ipath_flags & IPATH_PRESENT) ||
@@ -422,16 +400,22 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 		goto bail;
 	}

-	/* need total length before first word written */
-	/* +1 word is for the qword padding */
-	plen = sizeof(u32) + dp.len;
-
-	if ((plen + 4) > dd->ipath_ibmaxlen) {
+	/*
+	 * need total length before first word written, plus 2 Dwords. One Dword
+	 * is for padding so we get the full user data when not aligned on
+	 * a word boundary. The other Dword is to make sure we have room for the
+	 * ICRC which gets tacked on later.
+	 */
+	maxlen_reserve = 2 * sizeof(u32);
+	if (dp.len > dd->ipath_ibmaxlen - maxlen_reserve) {
 		ipath_dbg("Pkt len 0x%x > ibmaxlen %x\n",
-			  plen - 4, dd->ipath_ibmaxlen);
+			  dp.len, dd->ipath_ibmaxlen);
 		ret = -EINVAL;
-		goto bail;	/* before writing pbc */
+		goto bail;
 	}
+
+	plen = sizeof(u32) + dp.len;
+
 	tmpbuf = vmalloc(plen);
 	if (!tmpbuf) {
 		dev_info(&dd->pcidev->dev, "Unable to allocate tmp buffer, "
@@ -473,11 +457,11 @@ static ssize_t ipath_diagpkt_write(struct file *fp,
 	 */
 	if (dd->ipath_flags & IPATH_PIO_FLUSH_WC) {
 		ipath_flush_wc();
-		__iowrite32_copy(piobuf + 2, tmpbuf, clen - 1);
+		__iowrite32_copy(piobuf + 2, tmpbuf, plen - 1);
 		ipath_flush_wc();
-		__raw_writel(tmpbuf[clen - 1], piobuf + clen + 1);
+		__raw_writel(tmpbuf[plen - 1], piobuf + plen + 1);
 	} else
-		__iowrite32_copy(piobuf + 2, tmpbuf, clen);
+		__iowrite32_copy(piobuf + 2, tmpbuf, plen);

 	ipath_flush_wc();

--
1.9.1





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