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authorHauke Mehrtens <hauke@hauke-m.de>2018-02-12 23:59:51 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-20 10:20:55 +0100
commitae4199db18af1c4a5beee9288b0ba6c15c420922 (patch)
parent38ffd6c9cbde2e6df502605ead9214e314c9eb48 (diff)
uapi/if_ether.h: move __UAPI_DEF_ETHHDR libc define
commit da360299b6734135a5f66d7db458dcc7801c826a upstream. This fixes a compile problem of some user space applications by not including linux/libc-compat.h in uapi/if_ether.h. linux/libc-compat.h checks which "features" the header files, included from the libc, provide to make the Linux kernel uapi header files only provide no conflicting structures and enums. If a user application mixes kernel headers and libc headers it could happen that linux/libc-compat.h gets included too early where not all other libc headers are included yet. Then the linux/libc-compat.h would not prevent all the redefinitions and we run into compile problems. This patch removes the include of linux/libc-compat.h from uapi/if_ether.h to fix the recently introduced case, but not all as this is more or less impossible. It is no problem to do the check directly in the if_ether.h file and not in libc-compat.h as this does not need any fancy glibc header detection as glibc never provided struct ethhdr and should define __UAPI_DEF_ETHHDR by them self when they will provide this. The following test program did not compile correctly any more: #include <linux/if_ether.h> #include <netinet/in.h> #include <linux/in.h> int main(void) { return 0; } Fixes: 6926e041a892 ("uapi/if_ether.h: prevent redefinition of struct ethhdr") Reported-by: Guillaume Nault <g.nault@alphalink.fr> Cc: <stable@vger.kernel.org> # 4.15 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: David S. Miller <davem@davemloft.net> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 5 insertions, 7 deletions
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 60ec9114e28f..1d1157edcf40 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -23,7 +23,6 @@
#include <linux/types.h>
-#include <linux/libc-compat.h>
* IEEE 802.3 Ethernet magic constants. The frame sizes omit the preamble
@@ -151,6 +150,11 @@
* This is an Ethernet frame header.
+/* allow libcs like musl to deactivate this, glibc does not implement this. */
+#ifndef __UAPI_DEF_ETHHDR
+#define __UAPI_DEF_ETHHDR 1
struct ethhdr {
unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h
index fc29efaa918c..8254c937c9f4 100644
--- a/include/uapi/linux/libc-compat.h
+++ b/include/uapi/linux/libc-compat.h
@@ -264,10 +264,4 @@
#endif /* __GLIBC__ */
-/* Definitions for if_ether.h */
-/* allow libcs like musl to deactivate this, glibc does not implement this. */
-#ifndef __UAPI_DEF_ETHHDR
-#define __UAPI_DEF_ETHHDR 1
#endif /* _UAPI_LIBC_COMPAT_H */