[libc-commits] [libc] fedb9fd - [libc] Fix sendmsg iovec unpoisoning (#115057)

[via libc-commits]

Author: Michael Jones
Date: 2024-11-05T13:34:57-08:00
New Revision: fedb9fdb98314ff0ddff065dbd6ef8b2b7e6ec96

URL: https://github.com/llvm/llvm-project/commit/fedb9fdb98314ff0ddff065dbd6ef8b2b7e6ec96
DIFF: https://github.com/llvm/llvm-project/commit/fedb9fdb98314ff0ddff065dbd6ef8b2b7e6ec96.diff

LOG: [libc] Fix sendmsg iovec unpoisoning (#115057)

The unpoisoning for sendmsg had a typo where it would not unpoison all
of the elements in the iovec, causing msan errors. This patch fixes
that.

Added: 
    

Modified: 
    libc/src/sys/socket/linux/recvmsg.cpp

Removed: 
    


################################################################################
diff  --git a/libc/src/sys/socket/linux/recvmsg.cpp b/libc/src/sys/socket/linux/recvmsg.cpp
index 60bbc84877b850..e42b6346f330a0 100644
--- a/libc/src/sys/socket/linux/recvmsg.cpp
+++ b/libc/src/sys/socket/linux/recvmsg.cpp
@@ -20,8 +20,7 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
-LLVM_LIBC_FUNCTION(ssize_t, recvmsg,
-                   (int sockfd, struct msghdr *msg, int flags)) {
+LLVM_LIBC_FUNCTION(ssize_t, recvmsg, (int sockfd, msghdr *msg, int flags)) {
 #ifdef SYS_recvmsg
   ssize_t ret =
       LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_recvmsg, sockfd, msg, flags);
@@ -40,9 +39,11 @@ LLVM_LIBC_FUNCTION(ssize_t, recvmsg,
   }
 
   // Unpoison the msghdr, as well as all its components.
+  MSAN_UNPOISON(msg, sizeof(msghdr));
   MSAN_UNPOISON(msg->msg_name, msg->msg_namelen);
+
   for (size_t i = 0; i < msg->msg_iovlen; ++i) {
-    MSAN_UNPOISON(msg->msg_iov->iov_base, msg->msg_iov->iov_len);
+    MSAN_UNPOISON(msg->msg_iov[i].iov_base, msg->msg_iov[i].iov_len);
   }
   MSAN_UNPOISON(msg->msg_control, msg->msg_controllen);