mwave: fix read buffer overflow

Check whether index is within bounds before grabbing the element.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/char/mwave/mwavedd.c b/drivers/char/mwave/mwavedd.c
index 94ad2c3..a4ec50c 100644 (file)
--- a/drivers/char/mwave/mwavedd.c
+++ b/drivers/char/mwave/mwavedd.c
@@ -281,12 +281,6 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd,
                case IOCTL_MW_REGISTER_IPC: {
                        unsigned int ipcnum = (unsigned int) ioarg;
        
-                       PRINTK_3(TRACE_MWAVE,
-                               "mwavedd::mwave_ioctl IOCTL_MW_REGISTER_IPC"
-                               " ipcnum %x entry usIntCount %x\n",
-                               ipcnum,
-                               pDrvData->IPCs[ipcnum].usIntCount);
-       
                        if (ipcnum >= ARRAY_SIZE(pDrvData->IPCs)) {
                                PRINTK_ERROR(KERN_ERR_MWAVE
                                                "mwavedd::mwave_ioctl:"
@@ -295,6 +289,12 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd,
                                                ipcnum);
                                return -EINVAL;
                        }
+                       PRINTK_3(TRACE_MWAVE,
+                               "mwavedd::mwave_ioctl IOCTL_MW_REGISTER_IPC"
+                               " ipcnum %x entry usIntCount %x\n",
+                               ipcnum,
+                               pDrvData->IPCs[ipcnum].usIntCount);
+
                        lock_kernel();
                        pDrvData->IPCs[ipcnum].bIsHere = FALSE;
                        pDrvData->IPCs[ipcnum].bIsEnabled = TRUE;
@@ -310,11 +310,6 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd,
                case IOCTL_MW_GET_IPC: {
                        unsigned int ipcnum = (unsigned int) ioarg;
        
-                       PRINTK_3(TRACE_MWAVE,
-                               "mwavedd::mwave_ioctl IOCTL_MW_GET_IPC"
-                               " ipcnum %x, usIntCount %x\n",
-                               ipcnum,
-                               pDrvData->IPCs[ipcnum].usIntCount);
                        if (ipcnum >= ARRAY_SIZE(pDrvData->IPCs)) {
                                PRINTK_ERROR(KERN_ERR_MWAVE
                                                "mwavedd::mwave_ioctl:"
@@ -322,6 +317,11 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd,
                                                " Invalid ipcnum %x\n", ipcnum);
                                return -EINVAL;
                        }
+                       PRINTK_3(TRACE_MWAVE,
+                               "mwavedd::mwave_ioctl IOCTL_MW_GET_IPC"
+                               " ipcnum %x, usIntCount %x\n",
+                               ipcnum,
+                               pDrvData->IPCs[ipcnum].usIntCount);
        
                        lock_kernel();
                        if (pDrvData->IPCs[ipcnum].bIsEnabled == TRUE) {