[patch 13/60] I4L: fix isdn_ioctl memory overrun vulnerability

[Greg KH <gregkh@suse.de>]

2.6.23-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Karsten Keil <kkeil@suse.de>

patch eafe1aa37e6ec2d56f14732b5240c4dd09f0613a in mainline.

Fix possible memory overrun issue in the isdn ioctl code.  Found by ADLAB
<adlab@venustech.com.cn>

Signed-off-by: Karsten Keil <kkeil@suse.de>
Cc: ADLAB <adlab@venustech.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/isdn/i4l/isdn_common.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -1515,6 +1515,7 @@ isdn_ioctl(struct inode *inode, struct f
 					if (copy_from_user(&iocts, argp,
 					     sizeof(isdn_ioctl_struct)))
 						return -EFAULT;
+					iocts.drvid[sizeof(iocts.drvid)-1] = 0;
 					if (strlen(iocts.drvid)) {
 						if ((p = strchr(iocts.drvid, ',')))
 							*p = 0;
@@ -1599,6 +1600,7 @@ isdn_ioctl(struct inode *inode, struct f
 					if (copy_from_user(&iocts, argp,
 					     sizeof(isdn_ioctl_struct)))
 						return -EFAULT;
+					iocts.drvid[sizeof(iocts.drvid)-1] = 0;
 					if (strlen(iocts.drvid)) {
 						drvidx = -1;
 						for (i = 0; i < ISDN_MAX_DRIVERS; i++)
@@ -1643,7 +1645,7 @@ isdn_ioctl(struct inode *inode, struct f
 					} else {
 						p = (char __user *) iocts.arg;
 						for (i = 0; i < 10; i++) {
-							sprintf(bname, "%s%s",
+							snprintf(bname, sizeof(bname), "%s%s",
 								strlen(dev->drv[drvidx]->msn2eaz[i]) ?
 								dev->drv[drvidx]->msn2eaz[i] : "_",
 								(i < 9) ? "," : "\0");
@@ -1673,6 +1675,7 @@ isdn_ioctl(struct inode *inode, struct f
 					char *p;
 					if (copy_from_user(&iocts, argp, sizeof(isdn_ioctl_struct)))
 						return -EFAULT;
+					iocts.drvid[sizeof(iocts.drvid)-1] = 0;
 					if (strlen(iocts.drvid)) {
 						if ((p = strchr(iocts.drvid, ',')))
 							*p = 0;

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