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authorDavid S. Miller <davem@davemloft.net>2017-01-04 13:24:19 -0500
committerDavid S. Miller <davem@davemloft.net>2017-01-04 13:24:19 -0500
commitac4340fc3ce0e0b1cb627b05d6dcbd473544d7b3 (patch)
tree4987c1a7d7ce5273097bab8debde9ba2fde343ee /net/compat.c
parent1ff8cebf49ed9e9ca2ae44b5c4176aef9c21af9c (diff)
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net: Assert at build time the assumptions we make about the CMSG header.
It must always be the case that CMSG_ALIGN(sizeof(hdr)) == sizeof(hdr). Otherwise there are missing adjustments in the various calculations that parse and build these things. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/compat.c')
-rw-r--r--net/compat.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/compat.c b/net/compat.c
index 4e27dd1cd3a6..ba3ac722714d 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -130,6 +130,9 @@ int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
__kernel_size_t kcmlen, tmp;
int err = -EFAULT;
+ BUILD_BUG_ON(sizeof(struct compat_cmsghdr) !=
+ CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)));
+
kcmlen = 0;
kcmsg_base = kcmsg = (struct cmsghdr *)stackbuf;
ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);