diff options
authorMike Frysinger <>2012-08-18 16:11:37 -0400
committerGreg Kroah-Hartman <>2012-09-14 10:00:21 -0700
commite9497730c0f0b2b15006a869a2d3ed6febce5f1b (patch)
parent0522ba5d15022bca061c7c73c811eaed916bb369 (diff)
x32: Use compat shims for {g,s}etsockopt
commit 515c7af85ed92696c311c53d53cb4898ff32d784 upstream. Some of the arguments to {g,s}etsockopt are passed in userland pointers. If we try to use the 64bit entry point, we end up sometimes failing. For example, dhcpcd doesn't run in x32: # dhcpcd eth0 dhcpcd[1979]: version 5.5.6 starting dhcpcd[1979]: eth0: broadcasting for a lease dhcpcd[1979]: eth0: open_socket: Invalid argument dhcpcd[1979]: eth0: send_raw_packet: Bad file descriptor The code in particular is getting back EINVAL when doing: struct sock_fprog pf; setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &pf, sizeof(pf)); Diving into the kernel code, we can see: include/linux/filter.h: struct sock_fprog { unsigned short len; struct sock_filter __user *filter; }; net/core/sock.c: case SO_ATTACH_FILTER: ret = -EINVAL; if (optlen == sizeof(struct sock_fprog)) { struct sock_fprog fprog; ret = -EFAULT; if (copy_from_user(&fprog, optval, sizeof(fprog))) break; ret = sk_attach_filter(&fprog, sk); } break; arch/x86/syscalls/syscall_64.tbl: 54 common setsockopt sys_setsockopt 55 common getsockopt sys_getsockopt So for x64, sizeof(sock_fprog) is 16 bytes. For x86/x32, it's 8 bytes. This comes down to the pointer being 32bit for x32, which means we need to do structure size translation. But since x32 comes in directly to sys_setsockopt, it doesn't get translated like x86. After changing the syscall table and rebuilding glibc with the new kernel headers, dhcp runs fine in an x32 userland. Oddly, it seems like Linus noted the same thing during the initial port, but I guess that was missed/lost along the way: [ hpa: tagging for -stable since this is an ABI fix. ] Bugzilla: Reported-by: Mads <> Signed-off-by: Mike Frysinger <> Link: Cc: H. J. Lu <> Signed-off-by: H. Peter Anvin <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index dd29a9ea27c..fd1f1034813 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -60,8 +60,8 @@
51 common getsockname sys_getsockname
52 common getpeername sys_getpeername
53 common socketpair sys_socketpair
-54 common setsockopt sys_setsockopt
-55 common getsockopt sys_getsockopt
+54 64 setsockopt sys_setsockopt
+55 64 getsockopt sys_getsockopt
56 common clone stub_clone
57 common fork stub_fork
58 common vfork stub_vfork
@@ -351,3 +351,5 @@
538 x32 sendmmsg compat_sys_sendmmsg
539 x32 process_vm_readv compat_sys_process_vm_readv
540 x32 process_vm_writev compat_sys_process_vm_writev
+541 x32 setsockopt compat_sys_setsockopt
+542 x32 getsockopt compat_sys_getsockopt