From fd75e4d264d305347647a29ae2dab56c9f3967c9 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Sun, 22 Oct 2017 14:56:12 -0700 Subject: [PATCH] uml: Add 4.9 kernel patches 102-pseudo-random-mac.patch required an update to the new style asynchronous crypto Signed-off-by: Florian Fainelli --- ...-setjmp-symbol-clashes-with-libpthre.patch | 130 +++++++++++ ...-building-and-running-on-older-hosts.patch | 99 ++++++++ ...-check-for-PTRACE_GETRESET-SETREGSET.patch | 29 +++ ...ix-check-for-_xstate-for-older-hosts.patch | 46 ++++ .../uml/patches-4.9/101-mconsole-exec.patch | 211 ++++++++++++++++++ .../patches-4.9/102-pseudo-random-mac.patch | 131 +++++++++++ 6 files changed, 646 insertions(+) create mode 100644 target/linux/uml/patches-4.9/000-um-Avoid-longjmp-setjmp-symbol-clashes-with-libpthre.patch create mode 100644 target/linux/uml/patches-4.9/001-um-Allow-building-and-running-on-older-hosts.patch create mode 100644 target/linux/uml/patches-4.9/002-um-Correctly-check-for-PTRACE_GETRESET-SETREGSET.patch create mode 100644 target/linux/uml/patches-4.9/003-um-Fix-check-for-_xstate-for-older-hosts.patch create mode 100644 target/linux/uml/patches-4.9/101-mconsole-exec.patch create mode 100644 target/linux/uml/patches-4.9/102-pseudo-random-mac.patch diff --git a/target/linux/uml/patches-4.9/000-um-Avoid-longjmp-setjmp-symbol-clashes-with-libpthre.patch b/target/linux/uml/patches-4.9/000-um-Avoid-longjmp-setjmp-symbol-clashes-with-libpthre.patch new file mode 100644 index 0000000000..02149eea7a --- /dev/null +++ b/target/linux/uml/patches-4.9/000-um-Avoid-longjmp-setjmp-symbol-clashes-with-libpthre.patch @@ -0,0 +1,130 @@ +From f44f1e7da7c8e3f4575d5d61c4df978496903fcc Mon Sep 17 00:00:00 2001 +From: Florian Fainelli +Date: Tue, 23 May 2017 17:32:31 -0700 +Subject: [PATCH] um: Avoid longjmp/setjmp symbol clashes with libpthread.a + +[ Upstream commit f44f1e7da7c8e3f4575d5d61c4df978496903fcc ] + +Building a statically linked UML kernel on a Centos 6.9 host resulted in +the following linking failure (GCC 4.4, glibc-2.12): + +/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o): +In function `siglongjmp': +(.text+0x8490): multiple definition of `longjmp' +arch/x86/um/built-in.o:/local/users/fainelli/openwrt/trunk/build_dir/target-x86_64_musl/linux-uml/linux-4.4.69/arch/x86/um/setjmp_64.S:44: +first defined here +/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/libpthread.a(libpthread.o): +In function `sem_open': +(.text+0x77cd): warning: the use of `mktemp' is dangerous, better use +`mkstemp' +collect2: ld returned 1 exit status +make[4]: *** [vmlinux] Error 1 + +Adopt a solution similar to the one done for vmap where we define +longjmp/setjmp to be kernel_longjmp/setjmp. In the process, make sure we +do rename the functions in arch/x86/um/setjmp_*.S accordingly. + +Fixes: a7df4716d195 ("um: link with -lpthread") +Signed-off-by: Florian Fainelli +Signed-off-by: Richard Weinberger +--- + arch/um/Makefile | 4 ++++ + arch/x86/um/setjmp_32.S | 16 ++++++++-------- + arch/x86/um/setjmp_64.S | 16 ++++++++-------- + 3 files changed, 20 insertions(+), 16 deletions(-) + +--- a/arch/um/Makefile ++++ b/arch/um/Makefile +@@ -59,10 +59,14 @@ KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_D + # Same things for in6addr_loopback and mktime - found in libc. For these two we + # only get link-time error, luckily. + # ++# -Dlongjmp=kernel_longjmp prevents anything from referencing the libpthread.a ++# embedded copy of longjmp, same thing for setjmp. ++# + # These apply to USER_CFLAGS to. + + KBUILD_CFLAGS += $(CFLAGS) $(CFLAGS-y) -D__arch_um__ \ + $(ARCH_INCLUDE) $(MODE_INCLUDE) -Dvmap=kernel_vmap \ ++ -Dlongjmp=kernel_longjmp -Dsetjmp=kernel_setjmp \ + -Din6addr_loopback=kernel_in6addr_loopback \ + -Din6addr_any=kernel_in6addr_any -Dstrrchr=kernel_strrchr + +--- a/arch/x86/um/setjmp_32.S ++++ b/arch/x86/um/setjmp_32.S +@@ -16,9 +16,9 @@ + + .text + .align 4 +- .globl setjmp +- .type setjmp, @function +-setjmp: ++ .globl kernel_setjmp ++ .type kernel_setjmp, @function ++kernel_setjmp: + #ifdef _REGPARM + movl %eax,%edx + #else +@@ -35,13 +35,13 @@ setjmp: + movl %ecx,20(%edx) # Return address + ret + +- .size setjmp,.-setjmp ++ .size kernel_setjmp,.-kernel_setjmp + + .text + .align 4 +- .globl longjmp +- .type longjmp, @function +-longjmp: ++ .globl kernel_longjmp ++ .type kernel_longjmp, @function ++kernel_longjmp: + #ifdef _REGPARM + xchgl %eax,%edx + #else +@@ -55,4 +55,4 @@ longjmp: + movl 16(%edx),%edi + jmp *20(%edx) + +- .size longjmp,.-longjmp ++ .size kernel_longjmp,.-kernel_longjmp +--- a/arch/x86/um/setjmp_64.S ++++ b/arch/x86/um/setjmp_64.S +@@ -18,9 +18,9 @@ + + .text + .align 4 +- .globl setjmp +- .type setjmp, @function +-setjmp: ++ .globl kernel_setjmp ++ .type kernel_setjmp, @function ++kernel_setjmp: + pop %rsi # Return address, and adjust the stack + xorl %eax,%eax # Return value + movq %rbx,(%rdi) +@@ -34,13 +34,13 @@ setjmp: + movq %rsi,56(%rdi) # Return address + ret + +- .size setjmp,.-setjmp ++ .size kernel_setjmp,.-kernel_setjmp + + .text + .align 4 +- .globl longjmp +- .type longjmp, @function +-longjmp: ++ .globl kernel_longjmp ++ .type kernel_longjmp, @function ++kernel_longjmp: + movl %esi,%eax # Return value (int) + movq (%rdi),%rbx + movq 8(%rdi),%rsp +@@ -51,4 +51,4 @@ longjmp: + movq 48(%rdi),%r15 + jmp *56(%rdi) + +- .size longjmp,.-longjmp ++ .size kernel_longjmp,.-kernel_longjmp diff --git a/target/linux/uml/patches-4.9/001-um-Allow-building-and-running-on-older-hosts.patch b/target/linux/uml/patches-4.9/001-um-Allow-building-and-running-on-older-hosts.patch new file mode 100644 index 0000000000..9de557bfd5 --- /dev/null +++ b/target/linux/uml/patches-4.9/001-um-Allow-building-and-running-on-older-hosts.patch @@ -0,0 +1,99 @@ +From 0a987645672ebde7844a9c0732a5a25f3d4bb6c6 Mon Sep 17 00:00:00 2001 +From: Florian Fainelli +Date: Thu, 25 May 2017 11:36:26 -0700 +Subject: [PATCH] um: Allow building and running on older hosts + +[ Upstream commit 0a987645672ebde7844a9c0732a5a25f3d4bb6c6 ] + +Commit a78ff1112263 ("um: add extended processor state save/restore +support") and b6024b21fec8 ("um: extend fpstate to _xstate to support +YMM registers") forced the use of the x86 FP _xstate and +PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to +build UML nor run it anymore with these two commits applied because we +don't have definitions for struct _xstate nor these two ptrace requests. + +We can determine at build time which fp context structure to check +against, just like we can keep using the old i387 fp save/restore if +PTRACE_GETRESET/SETREGSET are not defined. + +Fixes: a78ff1112263 ("um: add extended processor state save/restore support") +Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers") +Signed-off-by: Florian Fainelli +Signed-off-by: Richard Weinberger +--- + arch/x86/um/os-Linux/registers.c | 12 ++++++++---- + arch/x86/um/user-offsets.c | 4 ++++ + 2 files changed, 12 insertions(+), 4 deletions(-) + +--- a/arch/x86/um/os-Linux/registers.c ++++ b/arch/x86/um/os-Linux/registers.c +@@ -26,6 +26,7 @@ int save_i387_registers(int pid, unsigne + + int save_fp_registers(int pid, unsigned long *fp_regs) + { ++#ifdef PTRACE_GETREGSET + struct iovec iov; + + if (have_xstate_support) { +@@ -34,9 +35,9 @@ int save_fp_registers(int pid, unsigned + if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0) + return -errno; + return 0; +- } else { ++ } else ++#endif + return save_i387_registers(pid, fp_regs); +- } + } + + int restore_i387_registers(int pid, unsigned long *fp_regs) +@@ -48,6 +49,7 @@ int restore_i387_registers(int pid, unsi + + int restore_fp_registers(int pid, unsigned long *fp_regs) + { ++#ifdef PTRACE_SETREGSET + struct iovec iov; + + if (have_xstate_support) { +@@ -56,9 +58,9 @@ int restore_fp_registers(int pid, unsign + if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0) + return -errno; + return 0; +- } else { ++ } else ++#endif + return restore_i387_registers(pid, fp_regs); +- } + } + + #ifdef __i386__ +@@ -122,6 +124,7 @@ int put_fp_registers(int pid, unsigned l + + void arch_init_registers(int pid) + { ++#ifdef PTRACE_GETREGSET + struct _xstate fp_regs; + struct iovec iov; + +@@ -129,6 +132,7 @@ void arch_init_registers(int pid) + iov.iov_len = sizeof(struct _xstate); + if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0) + have_xstate_support = 1; ++#endif + } + #endif + +--- a/arch/x86/um/user-offsets.c ++++ b/arch/x86/um/user-offsets.c +@@ -50,7 +50,11 @@ void foo(void) + DEFINE(HOST_GS, GS); + DEFINE(HOST_ORIG_AX, ORIG_EAX); + #else ++#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET) + DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long)); ++#else ++ DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long)); ++#endif + DEFINE_LONGS(HOST_BX, RBX); + DEFINE_LONGS(HOST_CX, RCX); + DEFINE_LONGS(HOST_DI, RDI); diff --git a/target/linux/uml/patches-4.9/002-um-Correctly-check-for-PTRACE_GETRESET-SETREGSET.patch b/target/linux/uml/patches-4.9/002-um-Correctly-check-for-PTRACE_GETRESET-SETREGSET.patch new file mode 100644 index 0000000000..79beb823c2 --- /dev/null +++ b/target/linux/uml/patches-4.9/002-um-Correctly-check-for-PTRACE_GETRESET-SETREGSET.patch @@ -0,0 +1,29 @@ +From 61e8d462457f202bf0c6393133425ad387825e22 Mon Sep 17 00:00:00 2001 +From: Richard Weinberger +Date: Thu, 6 Jul 2017 09:35:27 +0200 +Subject: [PATCH] um: Correctly check for PTRACE_GETRESET/SETREGSET + +[ Upstream commit 61e8d462457f202bf0c6393133425ad387825e22 ] + +When checking for PTRACE_GETRESET/SETREGSET, make sure that +the correct header file is included. We need linux/ptrace.h +which contains all ptrace UAPI related defines. +Otherwise #if defined(PTRACE_GETRESET) is always false. + +Cc: Florian Fainelli +Signed-off-by: Richard Weinberger +--- + arch/x86/um/user-offsets.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/arch/x86/um/user-offsets.c ++++ b/arch/x86/um/user-offsets.c +@@ -5,7 +5,7 @@ + #include + #include + #define __FRAME_OFFSETS +-#include ++#include + #include + + #ifdef __i386__ diff --git a/target/linux/uml/patches-4.9/003-um-Fix-check-for-_xstate-for-older-hosts.patch b/target/linux/uml/patches-4.9/003-um-Fix-check-for-_xstate-for-older-hosts.patch new file mode 100644 index 0000000000..b31ca4191b --- /dev/null +++ b/target/linux/uml/patches-4.9/003-um-Fix-check-for-_xstate-for-older-hosts.patch @@ -0,0 +1,46 @@ +From 2fb44600fe784449404c6639de26af8361999ec7 Mon Sep 17 00:00:00 2001 +From: Florian Fainelli +Date: Tue, 18 Jul 2017 16:43:47 -0700 +Subject: [PATCH] um: Fix check for _xstate for older hosts + +Commit 0a987645672e ("um: Allow building and running on older +hosts") attempted to check for PTRACE_{GET,SET}REGSET under the premise +that these ptrace(2) parameters were directly linked with the presence +of the _xstate structure. + +After Richard's commit 61e8d462457f ("um: Correctly check for +PTRACE_GETRESET/SETREGSET") which properly included linux/ptrace.h +instead of asm/ptrace.h, we could get into the original build failure +that I reported: + +arch/x86/um/user-offsets.c: In function 'foo': +arch/x86/um/user-offsets.c:54: error: invalid application of 'sizeof' to +incomplete type 'struct _xstate' + +On this particular host, we do have PTRACE_GETREGSET and +PTRACE_SETREGSET defined in linux/ptrace.h, but not the structure +_xstate that should be pulled from the following include chain: signal.h +-> bits/sigcontext.h. + +Correctly fix this by checking for FP_XSTATE_MAGIC1 which is the correct +way to see if struct _xstate is available or not on the host. + +Fixes: 61e8d462457f ("um: Correctly check for PTRACE_GETRESET/SETREGSET") +Fixes: 0a987645672e ("um: Allow building and running on older hosts") +Signed-off-by: Florian Fainelli +Signed-off-by: Richard Weinberger +--- + arch/x86/um/user-offsets.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/arch/x86/um/user-offsets.c ++++ b/arch/x86/um/user-offsets.c +@@ -50,7 +50,7 @@ void foo(void) + DEFINE(HOST_GS, GS); + DEFINE(HOST_ORIG_AX, ORIG_EAX); + #else +-#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET) ++#ifdef FP_XSTATE_MAGIC1 + DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long)); + #else + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long)); diff --git a/target/linux/uml/patches-4.9/101-mconsole-exec.patch b/target/linux/uml/patches-4.9/101-mconsole-exec.patch new file mode 100644 index 0000000000..6682338f39 --- /dev/null +++ b/target/linux/uml/patches-4.9/101-mconsole-exec.patch @@ -0,0 +1,211 @@ +# +# Minimalist mconsole exec patch +# +# 3.10 version (with bit more synchronous behavior) by fingon at iki dot fi +# Adaptation to kernel 3.3.8 made by David Fernández (david at dit.upm.es) for +# Starting point: mconsole-exec-2.6.30.patch for kernel 2.6.30 +# Author of original patch: Paolo Giarrusso, aka Blaisorblade +# (http://www.user-mode-linux.org/~blaisorblade) +# +# Known misfeatures: +# +# - If output is too long, blocks (and breaks horribly) +# (this misfeature from 3.10 patches, when minimalizing the patch; +# workaround: redirect to a shared filesystem if long output is expected) +# +# - Nothing useful is done with stdin +# +--- a/arch/um/drivers/mconsole.h ++++ b/arch/um/drivers/mconsole.h +@@ -85,6 +85,7 @@ extern void mconsole_cad(struct mc_reque + extern void mconsole_stop(struct mc_request *req); + extern void mconsole_go(struct mc_request *req); + extern void mconsole_log(struct mc_request *req); ++extern void mconsole_exec(struct mc_request *req); + extern void mconsole_proc(struct mc_request *req); + extern void mconsole_stack(struct mc_request *req); + +--- a/arch/um/drivers/mconsole_kern.c ++++ b/arch/um/drivers/mconsole_kern.c +@@ -4,6 +4,7 @@ + * Licensed under the GPL + */ + ++#include "linux/kmod.h" + #include + #include + #include +@@ -24,6 +25,7 @@ + #include + #include + #include ++#include + #include + #include + +@@ -121,6 +123,59 @@ void mconsole_log(struct mc_request *req + mconsole_reply(req, "", 0, 0); + } + ++void mconsole_exec(struct mc_request *req) ++{ ++ struct subprocess_info *sub_info; ++ int res, len; ++ struct file *out; ++ char buf[MCONSOLE_MAX_DATA]; ++ ++ char *envp[] = { ++ "HOME=/", "TERM=linux", ++ "PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin", ++ NULL ++ }; ++ char *argv[] = { ++ "/bin/sh", "-c", ++ req->request.data + strlen("exec "), ++ NULL ++ }; ++ ++ sub_info = call_usermodehelper_setup("/bin/sh", argv, envp, GFP_ATOMIC, NULL, NULL, NULL); ++ if (sub_info == NULL) { ++ mconsole_reply(req, "call_usermodehelper_setup failed", 1, 0); ++ return; ++ } ++ res = call_usermodehelper_stdoutpipe(sub_info, &out); ++ if (res < 0) { ++ kfree(sub_info); ++ mconsole_reply(req, "call_usermodehelper_stdoutpipe failed", 1, 0); ++ return; ++ } ++ ++ res = call_usermodehelper_exec(sub_info, UMH_WAIT_PROC); ++ if (res < 0) { ++ kfree(sub_info); ++ mconsole_reply(req, "call_usermodehelper_exec failed", 1, 0); ++ return; ++ } ++ ++ for (;;) { ++ len = out->f_op->read(out, buf, sizeof(buf), &out->f_pos); ++ if (len < 0) { ++ mconsole_reply(req, "reading output failed", 1, 0); ++ break; ++ } ++ if (len == 0) ++ break; ++ mconsole_reply_len(req, buf, len, 0, 1); ++ } ++ fput(out); ++ ++ mconsole_reply_len(req, NULL, 0, 0, 0); ++} ++ ++ + void mconsole_proc(struct mc_request *req) + { + struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt; +@@ -187,6 +242,7 @@ void mconsole_proc(struct mc_request *re + stop - pause the UML; it will do nothing until it receives a 'go' \n\ + go - continue the UML after a 'stop' \n\ + log - make UML enter into the kernel log\n\ ++ exec - pass to /bin/sh -c synchronously\n\ + proc - returns the contents of the UML's /proc/\n\ + stack - returns the stack of the specified pid\n\ + " +--- a/arch/um/drivers/mconsole_user.c ++++ b/arch/um/drivers/mconsole_user.c +@@ -30,6 +30,7 @@ static struct mconsole_command commands[ + { "stop", mconsole_stop, MCONSOLE_PROC }, + { "go", mconsole_go, MCONSOLE_INTR }, + { "log", mconsole_log, MCONSOLE_INTR }, ++ { "exec", mconsole_exec, MCONSOLE_PROC }, + { "proc", mconsole_proc, MCONSOLE_PROC }, + { "stack", mconsole_stack, MCONSOLE_INTR }, + }; +--- a/arch/um/os-Linux/file.c ++++ b/arch/um/os-Linux/file.c +@@ -554,6 +554,8 @@ int os_create_unix_socket(const char *fi + + addr.sun_family = AF_UNIX; + ++ if (len > sizeof(addr.sun_path)) ++ len = sizeof(addr.sun_path); + snprintf(addr.sun_path, len, "%s", file); + + err = bind(sock, (struct sockaddr *) &addr, sizeof(addr)); +--- a/include/linux/kmod.h ++++ b/include/linux/kmod.h +@@ -62,6 +62,7 @@ struct subprocess_info { + int wait; + int retval; + int (*init)(struct subprocess_info *info, struct cred *new); ++ struct file *stdout; + void (*cleanup)(struct subprocess_info *info); + void *data; + }; +@@ -102,4 +103,6 @@ extern int usermodehelper_read_trylock(v + extern long usermodehelper_read_lock_wait(long timeout); + extern void usermodehelper_read_unlock(void); + ++int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, struct file **filp); ++ + #endif /* __LINUX_KMOD_H__ */ +--- a/kernel/kmod.c ++++ b/kernel/kmod.c +@@ -39,6 +39,7 @@ + #include + #include + #include ++#include + #include + + #include +@@ -222,6 +223,28 @@ static int call_usermodehelper_exec_asyn + flush_signal_handlers(current, 1); + spin_unlock_irq(¤t->sighand->siglock); + ++ /* Install output when needed */ ++ if (sub_info->stdout) { ++ struct files_struct *f = current->files; ++ struct fdtable *fdt; ++ ++ sys_close(1); ++ sys_close(2); ++ get_file(sub_info->stdout); ++ fd_install(1, sub_info->stdout); ++ fd_install(2, sub_info->stdout); ++ spin_lock(&f->file_lock); ++ fdt = files_fdtable(f); ++ __set_bit(1, fdt->open_fds); ++ __clear_bit(1, fdt->close_on_exec); ++ __set_bit(2, fdt->open_fds); ++ __clear_bit(2, fdt->close_on_exec); ++ spin_unlock(&f->file_lock); ++ ++ /* disallow core files */ ++ current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0}; ++ } ++ + /* + * Our parent (unbound workqueue) runs with elevated scheduling + * priority. Avoid propagating that into the userspace child. +@@ -540,6 +563,20 @@ struct subprocess_info *call_usermodehel + } + EXPORT_SYMBOL(call_usermodehelper_setup); + ++int call_usermodehelper_stdoutpipe(struct subprocess_info *sub_info, ++ struct file **filp) ++{ ++ struct file *f[2]; ++ ++ if (create_pipe_files(f, 0)<0) ++ return PTR_ERR(f); ++ sub_info->stdout = f[1]; ++ *filp = f[0]; ++ return 0; ++} ++EXPORT_SYMBOL(call_usermodehelper_stdoutpipe); ++ ++ + /** + * call_usermodehelper_exec - start a usermode application + * @sub_info: information about the subprocessa diff --git a/target/linux/uml/patches-4.9/102-pseudo-random-mac.patch b/target/linux/uml/patches-4.9/102-pseudo-random-mac.patch new file mode 100644 index 0000000000..a31d75ff38 --- /dev/null +++ b/target/linux/uml/patches-4.9/102-pseudo-random-mac.patch @@ -0,0 +1,131 @@ +=============================================================================== + +This patch makes MAC addresses of network interfaces predictable. In +particular, it adds a small routine that computes MAC addresses of based on +a SHA1 hash of the virtual machine name and interface ID. + +TECHNICAL INFORMATION: + +Applies to vanilla kernel 3.9.4. + +=============================================================================== +--- a/arch/um/Kconfig.net ++++ b/arch/um/Kconfig.net +@@ -21,6 +21,19 @@ config UML_NET + enable at least one of the following transport options to actually + make use of UML networking. + ++config UML_NET_RANDOM_MAC ++ bool "Use random MAC addresses for network interfaces" ++ default n ++ depends on UML_NET ++ help ++ Virtual network devices inside a User-Mode Linux instance must be ++ assigned a MAC (Ethernet) address. If none is specified on the UML ++ command line, one must be automatically computed. If this option is ++ enabled, a randomly generated address is used. Otherwise, if this ++ option is disabled, the address is generated from a SHA1 hash of ++ the umid of the UML instance and the interface name. The latter choice ++ is useful to make MAC addresses predictable. ++ + config UML_NET_ETHERTAP + bool "Ethertap transport" + depends on UML_NET +--- a/arch/um/drivers/net_kern.c ++++ b/arch/um/drivers/net_kern.c +@@ -25,6 +25,14 @@ + #include + #include + ++#include ++#include ++#include ++#include ++#include ++#include ++#include "os.h" ++ + #define DRIVER_NAME "uml-netdev" + + static DEFINE_SPINLOCK(opened_lock); +@@ -295,11 +303,53 @@ static void uml_net_user_timer_expire(un + #endif + } + ++#ifndef CONFIG_UML_NET_RANDOM_MAC ++ ++/* Compute a SHA1 hash of the UML instance's id and ++ * * an interface name. */ ++static int compute_hash(const char *umid, const char *ifname, char *hash) ++{ ++ struct ahash_request *desc; ++ struct crypto_ahash *tfm; ++ struct scatterlist sg; ++ char vmif[1024]; ++ int ret; ++ ++ strcpy (vmif, umid); ++ strcat (vmif, ifname); ++ ++ tfm = crypto_alloc_ahash("sha1", 0, CRYPTO_ALG_ASYNC); ++ if (IS_ERR(tfm)) ++ return -ENOMEM; ++ ++ desc = ahash_request_alloc(tfm, GFP_KERNEL); ++ if (!desc) { ++ ret = -ENOMEM; ++ goto out; ++ } ++ ++ crypto_ahash_clear_flags(tfm, ~0); ++ ++ sg_init_table(&sg, 1); ++ sg_set_buf(&sg, vmif, strlen(vmif)); ++ ++ ahash_request_set_crypt(desc, &sg, hash, strlen(vmif)); ++ ++ ret = crypto_ahash_digest(desc); ++out: ++ crypto_free_ahash(tfm); ++ ++ return ret; ++} ++ ++#endif ++ + static void setup_etheraddr(struct net_device *dev, char *str) + { + unsigned char *addr = dev->dev_addr; + char *end; + int i; ++ u8 hash[SHA1_DIGEST_SIZE]; + + if (str == NULL) + goto random; +@@ -340,9 +390,26 @@ static void setup_etheraddr(struct net_d + return; + + random: ++#ifdef CONFIG_UML_NET_RANDOM_MAC + printk(KERN_INFO + "Choosing a random ethernet address for device %s\n", dev->name); + eth_hw_addr_random(dev); ++#else ++ printk(KERN_INFO ++ "Computing a digest to use as ethernet address for device %s\n", dev->name); ++ if (compute_hash(get_umid(), dev->name, hash) < 0) { ++ printk(KERN_WARNING ++ "Could not compute digest to use as ethernet address for device %s. " ++ "Using random address instead.\n", dev->name); ++ random_ether_addr(addr); ++ } ++ else { ++ for (i=0; i < 6; i++) ++ addr[i] = (hash[i] + hash[i+6]) % 0x100; ++ } ++ addr [0] &= 0xfe; /* clear multicast bit */ ++ addr [0] |= 0x02; /* set local assignment bit (IEEE802) */ ++#endif + } + + static DEFINE_SPINLOCK(devices_lock); -- 2.25.1