From fd75e4d264d305347647a29ae2dab56c9f3967c9 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Sun, 22 Oct 2017 14:56:12 -0700 Subject: 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 --- .../uml/patches-4.9/102-pseudo-random-mac.patch | 131 +++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 target/linux/uml/patches-4.9/102-pseudo-random-mac.patch (limited to 'target/linux/uml/patches-4.9/102-pseudo-random-mac.patch') 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); -- cgit v1.2.3