Re: Misc 2.5 Fixes: cp-user-cmpci

[Dipankar Sarma <dipankar@in.ibm.com>]

Fix copy/user problems. Not sure why cm_write() needs to do
acces_ok() on buffer twice. Also __get_user() return value isn't checked
in trans_ac3().


 sound/oss/cmpci.c |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)

diff -puN sound/oss/cmpci.c~cp-user-cmpci sound/oss/cmpci.c
--- linux-2.5.70-ds/sound/oss/cmpci.c~cp-user-cmpci	2003-06-08 15:36:16.000000000 +0530
+++ linux-2.5.70-ds-dipankar/sound/oss/cmpci.c	2003-06-08 20:39:03.000000000 +0530
@@ -588,7 +588,8 @@ static void trans_ac3(struct cm_state *s
 	unsigned short *src = (unsigned short *)source;
 
 	do {
-		data = (unsigned long) *src++;
+		__get_user(data, src);
+		src++;
 		data <<= 12;			// ok for 16-bit data
 		if (s->spdif_counter == 2 || s->spdif_counter == 3)
 			data |= 0x40000000;	// indicate AC-3 raw data
@@ -1600,9 +1601,9 @@ static ssize_t cm_write(struct file *fil
 			return -ENXIO;
 		if (!s->dma_adc.ready && (ret = prog_dmabuf(s, 1)))
 			return ret;
-		if (!access_ok(VERIFY_READ, buffer, count))
-			return -EFAULT;
 	}
+	if (!access_ok(VERIFY_READ, buffer, count))
+		return -EFAULT;
 	ret = 0;
 
 	while (count > 0) {
@@ -1662,15 +1663,21 @@ static ssize_t cm_write(struct file *fil
 			swptr = (swptr + 2 * cnt) % s->dma_dac.dmasize;
 		} else if (s->status & DO_DUAL_DAC) {
 			int	i;
-			unsigned long *src, *dst0, *dst1;
+			unsigned long *src, *dst0, *dst1, data;
 
 			src = (unsigned long *) buffer;
 			dst0 = (unsigned long *) (s->dma_dac.rawbuf + swptr);
 			dst1 = (unsigned long *) (s->dma_adc.rawbuf + swptr);
 			// copy left/right sample at one time
 			for (i = 0; i <= cnt / 4; i++) {
-				*dst0++ = *src++;
-				*dst1++ = *src++;
+				if (__get_user(data, src))
+					return ret ? ret : -EFAULT;
+				*dst0++ = data;
+				src++;
+				if (__get_user(data, src))
+					return ret ? ret : -EFAULT;
+				*dst1++ = data;
+				src++;
 			}
 			swptr = (swptr + cnt) % s->dma_dac.dmasize;
 		} else {

_