ipc: tighten msg copy loops
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/msgutil.c b/ipc/msgutil.c
index 0a5c8a9..b79582d 100644
--- a/ipc/msgutil.c
+++ b/ipc/msgutil.c
@@ -97,18 +97,14 @@
goto out_err;
}
- len -= alen;
- src = ((char __user *)src) + alen;
- seg = msg->next;
- while (len > 0) {
+ for (seg = msg->next; seg != NULL; seg = seg->next) {
+ len -= alen;
+ src = (char __user *)src + alen;
alen = min(len, DATALEN_SEG);
if (copy_from_user(seg + 1, src, alen)) {
err = -EFAULT;
goto out_err;
}
- seg = seg->next;
- len -= alen;
- src = ((char __user *)src) + alen;
}
err = security_msg_msg_alloc(msg);
@@ -135,15 +131,13 @@
alen = min(len, DATALEN_MSG);
memcpy(dst + 1, src + 1, alen);
- len -= alen;
- dst_pseg = dst->next;
- src_pseg = src->next;
- while (len > 0) {
+ for (dst_pseg = dst->next, src_pseg = src->next;
+ src_pseg != NULL;
+ dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) {
+
+ len -= alen;
alen = min(len, DATALEN_SEG);
memcpy(dst_pseg + 1, src_pseg + 1, alen);
- dst_pseg = dst_pseg->next;
- len -= alen;
- src_pseg = src_pseg->next;
}
dst->m_type = src->m_type;
@@ -166,16 +160,12 @@
if (copy_to_user(dest, msg + 1, alen))
return -1;
- len -= alen;
- dest = ((char __user *)dest) + alen;
- seg = msg->next;
- while (len > 0) {
+ for (seg = msg->next; seg != NULL; seg = seg->next) {
+ len -= alen;
+ dest = (char __user *)dest + alen;
alen = min(len, DATALEN_SEG);
if (copy_to_user(dest, seg + 1, alen))
return -1;
- len -= alen;
- dest = ((char __user *)dest) + alen;
- seg = seg->next;
}
return 0;
}
