From 8128a7e4fc2d83ed3e20fdb2ad868b1dedd2be4e Mon Sep 17 00:00:00 2001 From: Mikael Magnusson Date: Mon, 27 May 2019 22:48:10 +0200 Subject: [PATCH] busybox: fix: ip addr flush hangs when run by non-root user Add upstream patch from: https://git.busybox.net/busybox/commit/?id=028c5aa18b5273c029f0278232d922ee1a164de6 The patch fixes a problem with an infinite loop causing 100% CPU usage when running the following command /lib/preinit/10_indicate_preinit without the CAP_NET_ADMIN capability (such as in Docker): ip -4 address flush dev $pi_ifname Signed-off-by: Mikael Magnusson Signed-off-by: Hans Dedecker [refresh patch] --- package/utils/busybox/Makefile | 2 +- ...se-rtnl_send_check-on-flush-commands.patch | 214 ++++++++++++++++++ 2 files changed, 215 insertions(+), 1 deletion(-) create mode 100644 package/utils/busybox/patches/530-ip-use-rtnl_send_check-on-flush-commands.patch diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile index 8ccf4358af..ff25a35b6e 100644 --- a/package/utils/busybox/Makefile +++ b/package/utils/busybox/Makefile @@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=busybox PKG_VERSION:=1.30.1 -PKG_RELEASE:=2 +PKG_RELEASE:=3 PKG_FLAGS:=essential PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2 diff --git a/package/utils/busybox/patches/530-ip-use-rtnl_send_check-on-flush-commands.patch b/package/utils/busybox/patches/530-ip-use-rtnl_send_check-on-flush-commands.patch new file mode 100644 index 0000000000..0e8ec37f80 --- /dev/null +++ b/package/utils/busybox/patches/530-ip-use-rtnl_send_check-on-flush-commands.patch @@ -0,0 +1,214 @@ +From 028c5aa18b5273c029f0278232d922ee1a164de6 Mon Sep 17 00:00:00 2001 +From: Denys Vlasenko +Date: Wed, 22 May 2019 13:54:46 +0200 +Subject: ip: use rtnl_send_check() on flush commands, closes 6962 + +function old new delta +rtnl_send_check - 160 +160 +xrtnl_wilddump_request 64 66 +2 +ipneigh_list_or_flush 714 706 -8 +rtnl_send 69 - -69 +------------------------------------------------------------------------------ +(add/remove: 1/1 grow/shrink: 1/1 up/down: 162/-77) Total: 85 bytes + +Signed-off-by: Denys Vlasenko +--- + networking/libiproute/ipaddress.c | 6 ++++-- + networking/libiproute/ipneigh.c | 9 ++++---- + networking/libiproute/iproute.c | 5 ++++- + networking/libiproute/libnetlink.c | 43 +++++++++++++++++++++++++++++++------- + networking/libiproute/libnetlink.h | 19 +++++++++++++++-- + 5 files changed, 65 insertions(+), 17 deletions(-) + +--- a/networking/libiproute/ipaddress.c ++++ b/networking/libiproute/ipaddress.c +@@ -23,6 +23,7 @@ + + struct filter_t { + char *label; ++ /* Flush cmd buf. If !NULL, print_addrinfo() constructs flush commands in it */ + char *flushb; + struct rtnl_handle *rth; + int scope, scopemask; +@@ -34,6 +35,8 @@ struct filter_t { + smallint showqueue; + smallint oneline; + smallint up; ++ /* Misnomer. Does not mean "flushed something" */ ++ /* More like "flush commands were constructed by print_addrinfo()" */ + smallint flushed; + inet_prefix pfx; + } FIX_ALIASING; +@@ -201,7 +204,7 @@ static NOINLINE int print_linkinfo(const + + static int flush_update(void) + { +- if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { ++ if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + bb_perror_msg("can't send flush request"); + return -1; + } +@@ -507,7 +510,6 @@ int FAST_FUNC ipaddr_list_or_flush(char + xrtnl_dump_filter(&rth, store_nlmsg, &ainfo); + } + +- + if (G_filter.family && G_filter.family != AF_PACKET) { + struct nlmsg_list **lp; + lp = &linfo; +--- a/networking/libiproute/ipneigh.c ++++ b/networking/libiproute/ipneigh.c +@@ -32,7 +32,10 @@ struct filter_t { + int state; + int unused_only; + inet_prefix pfx; ++ /* Misnomer. Does not mean "flushed N something" */ ++ /* More like "no_of_flush_commands_constructed_by_print_neigh()" */ + int flushed; ++ /* Flush cmd buf. If !NULL, print_neigh() constructs flush commands in it */ + char *flushb; + int flushp; + int flushe; +@@ -45,7 +48,7 @@ typedef struct filter_t filter_t; + + static int flush_update(void) + { +- if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { ++ if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + bb_perror_msg("can't send flush request"); + return -1; + } +@@ -299,9 +302,7 @@ static int FAST_FUNC ipneigh_list_or_flu + G_filter.rth = &rth; + + while (round < MAX_ROUNDS) { +- if (xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH) < 0) { +- bb_perror_msg_and_die("can't send dump request"); +- } ++ xrtnl_wilddump_request(&rth, G_filter.family, RTM_GETNEIGH); + G_filter.flushed = 0; + if (xrtnl_dump_filter(&rth, print_neigh, NULL) < 0) { + bb_perror_msg_and_die("flush terminated"); +--- a/networking/libiproute/iproute.c ++++ b/networking/libiproute/iproute.c +@@ -26,7 +26,10 @@ + + struct filter_t { + int tb; ++ /* Misnomer. Does not mean "flushed something" */ ++ /* More like "flush commands were constructed by print_route()" */ + smallint flushed; ++ /* Flush cmd buf. If !NULL, print_route() constructs flush commands in it */ + char *flushb; + int flushp; + int flushe; +@@ -53,7 +56,7 @@ typedef struct filter_t filter_t; + + static int flush_update(void) + { +- if (rtnl_send(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { ++ if (rtnl_send_check(G_filter.rth, G_filter.flushb, G_filter.flushp) < 0) { + bb_perror_msg("can't send flush request"); + return -1; + } +--- a/networking/libiproute/libnetlink.c ++++ b/networking/libiproute/libnetlink.c +@@ -34,7 +34,7 @@ void FAST_FUNC xrtnl_open(struct rtnl_ha + rth->seq = time(NULL); + } + +-int FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) ++void FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type) + { + struct { + struct nlmsghdr nlh; +@@ -48,18 +48,45 @@ int FAST_FUNC xrtnl_wilddump_request(str + req.nlh.nlmsg_seq = rth->dump = ++rth->seq; + req.g.rtgen_family = family; + +- return rtnl_send(rth, (void*)&req, sizeof(req)); ++ rtnl_send(rth, (void*)&req, sizeof(req)); + } + +-//TODO: pass rth->fd instead of full rth? +-int FAST_FUNC rtnl_send(struct rtnl_handle *rth, char *buf, int len) ++/* A version which checks for e.g. EPERM errors. ++ * Try: setuidgid 1:1 ip addr flush dev eth0 ++ */ ++int FAST_FUNC rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) + { +- struct sockaddr_nl nladdr; ++ struct nlmsghdr *h; ++ int status; ++ char resp[1024]; ++ ++ status = write(rth->fd, buf, len); ++ if (status < 0) ++ return status; ++ ++ /* Check for immediate errors */ ++ status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK); ++ if (status < 0) { ++ if (errno == EAGAIN) /* if no error, this happens */ ++ return 0; ++ return -1; ++ } ++ ++ for (h = (struct nlmsghdr *)resp; ++ NLMSG_OK(h, status); ++ h = NLMSG_NEXT(h, status) ++ ) { ++ if (h->nlmsg_type == NLMSG_ERROR) { ++ struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h); ++ if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) ++ bb_error_msg("ERROR truncated"); ++ else ++ errno = -err->error; ++ return -1; ++ } ++ } + +- memset(&nladdr, 0, sizeof(nladdr)); +- nladdr.nl_family = AF_NETLINK; +- +- return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr)); ++ return 0; + } + + int FAST_FUNC rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) +--- a/networking/libiproute/libnetlink.h ++++ b/networking/libiproute/libnetlink.h +@@ -20,7 +20,7 @@ struct rtnl_handle { + + extern void xrtnl_open(struct rtnl_handle *rth) FAST_FUNC; + #define rtnl_close(rth) (close((rth)->fd)) +-extern int xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC; ++extern void xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC; + extern int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) FAST_FUNC; + extern int xrtnl_dump_filter(struct rtnl_handle *rth, + int (*filter)(const struct sockaddr_nl*, struct nlmsghdr *n, void*) FAST_FUNC, +@@ -34,8 +34,23 @@ extern int rtnl_talk(struct rtnl_handle + int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *), + void *jarg) FAST_FUNC; + +-extern int rtnl_send(struct rtnl_handle *rth, char *buf, int) FAST_FUNC; ++int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) FAST_FUNC; ++//TODO: pass rth->fd instead of full rth? ++static ALWAYS_INLINE void rtnl_send(struct rtnl_handle *rth, const void *buf, int len) ++{ ++ // Used to be: ++ //struct sockaddr_nl nladdr; ++ //memset(&nladdr, 0, sizeof(nladdr)); ++ //nladdr.nl_family = AF_NETLINK; ++ //return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr)); + ++ // iproute2-4.2.0 simplified the above to: ++ //return send(rth->fd, buf, len, 0); ++ ++ // We are using even shorter: ++ xwrite(rth->fd, buf, len); ++ // and convert to void, inline. ++} + + extern int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data) FAST_FUNC; + extern int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) FAST_FUNC; -- 2.25.1