[PATCH] sound/oss/emu10k1: handle userspace copy errors

Propagate copy_to/from_user() errors back through callers.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 38 insertions, 16 deletions

diff --git a/sound/oss/emu10k1/audio.c b/sound/oss/emu10k1/audio.c
index 86dd23974e05..49f902f35c28 100644
--- a/sound/oss/emu10k1/audio.c
+++ b/sound/oss/emu10k1/audio.c
@@ -111,9 +111,15 @@ static ssize_t emu10k1_audio_read(struct file *file, char __user *buffer, size_t
 
                 if ((bytestocopy >= wiinst->buffer.fragment_size)
                     || (bytestocopy >= count)) {
+                        int rc;
+
                         bytestocopy = min_t(u32, bytestocopy, count);
 
-                        emu10k1_wavein_xferdata(wiinst, (u8 __user *)buffer, &bytestocopy);
+                        rc = emu10k1_wavein_xferdata(wiinst,
+                                                     (u8 __user *)buffer,
+                                                     &bytestocopy);
+                        if (rc)
+                                return rc;
 
                         count -= bytestocopy;
                         buffer += bytestocopy;
diff --git a/sound/oss/emu10k1/cardwi.c b/sound/oss/emu10k1/cardwi.c
index 8bbf44b881b4..060d1be94d33 100644
--- a/sound/oss/emu10k1/cardwi.c
+++ b/sound/oss/emu10k1/cardwi.c
@@ -304,11 +304,12 @@ void emu10k1_wavein_getxfersize(struct wiinst *wiinst, u32 * size)
         }
 }
 
-static void copy_block(u8 __user *dst, u8 * src, u32 str, u32 len, u8 cov)
+static int copy_block(u8 __user *dst, u8 * src, u32 str, u32 len, u8 cov)
 {
-        if (cov == 1)
-                __copy_to_user(dst, src + str, len);
-        else {
+        if (cov == 1) {
+                if (__copy_to_user(dst, src + str, len))
+                        return -EFAULT;
+        } else {
                 u8 byte;
                 u32 i;
 
@@ -316,22 +317,26 @@ static void copy_block(u8 __user *dst, u8 * src, u32 str, u32 len, u8 cov)
 
                 for (i = 0; i < len; i++) {
                         byte = src[2 * i] ^ 0x80;
-                        __copy_to_user(dst + i, &byte, 1);
+                        if (__copy_to_user(dst + i, &byte, 1))
+                                return -EFAULT;
                 }
         }
+
+        return 0;
 }
 
-void emu10k1_wavein_xferdata(struct wiinst *wiinst, u8 __user *data, u32 * size)
+int emu10k1_wavein_xferdata(struct wiinst *wiinst, u8 __user *data, u32 * size)
 {
         struct wavein_buffer *buffer = &wiinst->buffer;
         u32 sizetocopy, sizetocopy_now, start;
         unsigned long flags;
+        int ret;
 
         sizetocopy = min_t(u32, buffer->size, *size);
         *size = sizetocopy;
 
         if (!sizetocopy)
-                return;
+                return 0;
 
         spin_lock_irqsave(&wiinst->lock, flags);
         start = buffer->pos;
@@ -345,11 +350,17 @@ void emu10k1_wavein_xferdata(struct wiinst *wiinst, u8 __user *data, u32 * size)
         if (sizetocopy > sizetocopy_now) {
                 sizetocopy -= sizetocopy_now;
 
-                copy_block(data, buffer->addr, start, sizetocopy_now, buffer->cov);
-                copy_block(data + sizetocopy_now, buffer->addr, 0, sizetocopy, buffer->cov);
+                ret = copy_block(data, buffer->addr, start, sizetocopy_now,
+                                 buffer->cov);
+                if (ret == 0)
+                        ret = copy_block(data + sizetocopy_now, buffer->addr, 0,
+                                         sizetocopy, buffer->cov);
         } else {
-                copy_block(data, buffer->addr, start, sizetocopy, buffer->cov);
+                ret = copy_block(data, buffer->addr, start, sizetocopy,
+                                 buffer->cov);
         }
+
+        return ret;
 }
 
 void emu10k1_wavein_update(struct emu10k1_card *card, struct wiinst *wiinst)
diff --git a/sound/oss/emu10k1/cardwi.h b/sound/oss/emu10k1/cardwi.h
index 15cfb9b35596..e82029b46ad1 100644
--- a/sound/oss/emu10k1/cardwi.h
+++ b/sound/oss/emu10k1/cardwi.h
@@ -83,7 +83,7 @@ void emu10k1_wavein_close(struct emu10k1_wavedevice *);
 void emu10k1_wavein_start(struct emu10k1_wavedevice *);
 void emu10k1_wavein_stop(struct emu10k1_wavedevice *);
 void emu10k1_wavein_getxfersize(struct wiinst *, u32 *);
-void emu10k1_wavein_xferdata(struct wiinst *, u8 __user *, u32 *);
+int emu10k1_wavein_xferdata(struct wiinst *, u8 __user *, u32 *);
 int emu10k1_wavein_setformat(struct emu10k1_wavedevice *, struct wave_format *);
 void emu10k1_wavein_update(struct emu10k1_card *, struct wiinst *);
 
diff --git a/sound/oss/emu10k1/passthrough.c b/sound/oss/emu10k1/passthrough.c
index 4e3baca7d41f..6d21d4368dec 100644
--- a/sound/oss/emu10k1/passthrough.c
+++ b/sound/oss/emu10k1/passthrough.c
@@ -162,12 +162,15 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
 
                 DPD(3, "prepend size %d, prepending %d bytes\n", pt->prepend_size, needed);
                 if (count < needed) {
-                        copy_from_user(pt->buf + pt->prepend_size, buffer, count);
+                        if (copy_from_user(pt->buf + pt->prepend_size,
+                                           buffer, count))
+                                return -EFAULT;
                         pt->prepend_size += count;
                         DPD(3, "prepend size now %d\n", pt->prepend_size);
                         return count;
                 }
-                copy_from_user(pt->buf + pt->prepend_size, buffer, needed);
+                if (copy_from_user(pt->buf + pt->prepend_size, buffer, needed))
+                        return -EFAULT;
                 r = pt_putblock(wave_dev, (u16 *) pt->buf, nonblock);
                 if (r)
                         return r;
@@ -178,7 +181,8 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
         blocks_copied = 0;
         while (blocks > 0) {
                 u16 __user *bufptr = (u16 __user *) buffer + (bytes_copied/2);
-                copy_from_user(pt->buf, bufptr, PT_BLOCKSIZE);
+                if (copy_from_user(pt->buf, bufptr, PT_BLOCKSIZE))
+                        return -EFAULT;
                 r = pt_putblock(wave_dev, (u16 *)pt->buf, nonblock);
                 if (r) {
                         if (bytes_copied)
@@ -193,7 +197,8 @@ ssize_t emu10k1_pt_write(struct file *file, const char __user *buffer, size_t co
         i = count - bytes_copied;
         if (i) {
                 pt->prepend_size = i;
-                copy_from_user(pt->buf, buffer + bytes_copied, i);
+                if (copy_from_user(pt->buf, buffer + bytes_copied, i))
+                        return -EFAULT;
                 bytes_copied += i;
                 DPD(3, "filling prepend buffer with %d bytes", i);
         }