From 30c93547cd14db1ae44ea9e32bf36a2c2b152c07 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Sun, 28 Aug 2022 03:33:37 +0200
Subject: kmsg: factorize uint32_t into an alignment type
and restore the checks for offset alignment in the message, even if
currently it is trivially always alright.
---
ipc/ipc_kmsg.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/ipc/ipc_kmsg.c b/ipc/ipc_kmsg.c
index cf7ec77d..8f54f81d 100644
--- a/ipc/ipc_kmsg.c
+++ b/ipc/ipc_kmsg.c
@@ -69,9 +69,11 @@
#endif
/* msg body is always aligned to 4 bytes */
-#define msg_is_misaligned(x) ( ((vm_offset_t)(x)) & (sizeof(uint32_t)-1) )
+typedef uint32_t msg_align_t;
+
+#define msg_is_misaligned(x) ( ((vm_offset_t)(x)) & (sizeof(msg_align_t)-1) )
#define msg_align(x) \
- ( ( ((vm_offset_t)(x)) + (sizeof(uint32_t)-1) ) & ~(sizeof(uint32_t)-1) )
+ ( ( ((vm_offset_t)(x)) + (sizeof(msg_align_t)-1) ) & ~(sizeof(msg_align_t)-1) )
ipc_kmsg_t ipc_kmsg_cache[NCPUS];
@@ -1377,6 +1379,9 @@ ipc_kmsg_copyin_body(
} else {
vm_offset_t addr;
+ if (sizeof(msg_align_t) > sizeof(mach_msg_type_t))
+ saddr = msg_align(saddr);
+
if ((eaddr - saddr) < sizeof(vm_offset_t)) {
ipc_kmsg_clean_partial(kmsg, taddr, FALSE, 0);
return MACH_SEND_MSG_TOO_SMALL;
@@ -2424,6 +2429,9 @@ ipc_kmsg_copyout_body(
} else {
vm_offset_t data;
+ if (sizeof(msg_align_t) > sizeof(mach_msg_type_t))
+ saddr = msg_align(saddr);
+
data = * (vm_offset_t *) saddr;
/* copyout memory carried in the message */
--
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