Revision 633593a808980f82d251d0ca89730d8bb8b0220c authored by Eric Dumazet on 10 March 2022, 00:11:45 UTC, committed by Jakub Kicinski on 10 March 2022, 22:46:42 UTC
syzbot reported a kernel infoleak [1] of 4 bytes.

After analysis, it turned out r->idiag_expires is not initialized
if inet_sctp_diag_fill() calls inet_diag_msg_common_fill()

Make sure to clear idiag_timer/idiag_retrans/idiag_expires
and let inet_diag_msg_sctpasoc_fill() fill them again if needed.

[1]

BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:154 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x6ef/0x25a0 lib/iov_iter.c:668
 instrument_copy_to_user include/linux/instrumented.h:121 [inline]
 copyout lib/iov_iter.c:154 [inline]
 _copy_to_iter+0x6ef/0x25a0 lib/iov_iter.c:668
 copy_to_iter include/linux/uio.h:162 [inline]
 simple_copy_to_iter+0xf3/0x140 net/core/datagram.c:519
 __skb_datagram_iter+0x2d5/0x11b0 net/core/datagram.c:425
 skb_copy_datagram_iter+0xdc/0x270 net/core/datagram.c:533
 skb_copy_datagram_msg include/linux/skbuff.h:3696 [inline]
 netlink_recvmsg+0x669/0x1c80 net/netlink/af_netlink.c:1977
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 __sys_recvfrom+0x795/0xa10 net/socket.c:2097
 __do_sys_recvfrom net/socket.c:2115 [inline]
 __se_sys_recvfrom net/socket.c:2111 [inline]
 __x64_sys_recvfrom+0x19d/0x210 net/socket.c:2111
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3247 [inline]
 __kmalloc_node_track_caller+0xe0c/0x1510 mm/slub.c:4975
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1158 [inline]
 netlink_dump+0x3e5/0x16c0 net/netlink/af_netlink.c:2248
 __netlink_dump_start+0xcf8/0xe90 net/netlink/af_netlink.c:2373
 netlink_dump_start include/linux/netlink.h:254 [inline]
 inet_diag_handler_cmd+0x2e7/0x400 net/ipv4/inet_diag.c:1341
 sock_diag_rcv_msg+0x24a/0x620
 netlink_rcv_skb+0x40c/0x7e0 net/netlink/af_netlink.c:2494
 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:277
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x1093/0x1360 net/netlink/af_netlink.c:1343
 netlink_sendmsg+0x14d9/0x1720 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 sock_write_iter+0x594/0x690 net/socket.c:1061
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_write+0x52c/0x1500 fs/read_write.c:851
 vfs_writev fs/read_write.c:924 [inline]
 do_writev+0x645/0xe00 fs/read_write.c:967
 __do_sys_writev fs/read_write.c:1040 [inline]
 __se_sys_writev fs/read_write.c:1037 [inline]
 __x64_sys_writev+0xe5/0x120 fs/read_write.c:1037
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Bytes 68-71 of 2508 are uninitialized
Memory access of size 2508 starts at ffff888114f9b000
Data copied to user address 00007f7fe09ff2e0

CPU: 1 PID: 3478 Comm: syz-executor306 Not tainted 5.17.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 8f840e47f190 ("sctp: add the sctp_diag.c file")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20220310001145.297371-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
1 parent 26183cf
Raw File
Makefile.host
# SPDX-License-Identifier: GPL-2.0

# LEX
# ---------------------------------------------------------------------------
quiet_cmd_flex = LEX     $@
      cmd_flex = $(LEX) -o$@ -L $<

$(obj)/%.lex.c: $(src)/%.l FORCE
	$(call if_changed,flex)

# YACC
# ---------------------------------------------------------------------------
quiet_cmd_bison = YACC    $(basename $@).[ch]
      cmd_bison = $(YACC) -o $(basename $@).c --defines=$(basename $@).h -t -l $<

$(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
	$(call if_changed,bison)

# ==========================================================================
# Building binaries on the host system
# Binaries are used during the compilation of the kernel, for example
# to preprocess a data file.
#
# Both C and C++ are supported, but preferred language is C for such utilities.
#
# Sample syntax (see Documentation/kbuild/makefiles.rst for reference)
# hostprogs := bin2hex
# Will compile bin2hex.c and create an executable named bin2hex
#
# hostprogs     := lxdialog
# lxdialog-objs := checklist.o lxdialog.o
# Will compile lxdialog.c and checklist.c, and then link the executable
# lxdialog, based on checklist.o and lxdialog.o
#
# hostprogs       := qconf
# qconf-cxxobjs   := qconf.o
# qconf-objs      := menu.o
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf

# C code
# Executables compiled from a single .c file
host-csingle	:= $(foreach m,$(hostprogs), \
			$(if $($(m)-objs)$($(m)-cxxobjs),,$(m)))

# C executables linked based on several .o files
host-cmulti	:= $(foreach m,$(hostprogs),\
		   $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))

# Object (.o) files compiled from .c files
host-cobjs	:= $(sort $(foreach m,$(hostprogs),$($(m)-objs)))

# C++ code
# C++ executables compiled from at least one .cc file
# and zero or more .c files
host-cxxmulti	:= $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m)))

# C++ Object (.o) files compiled from .cc files
host-cxxobjs	:= $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))

host-csingle	:= $(addprefix $(obj)/,$(host-csingle))
host-cmulti	:= $(addprefix $(obj)/,$(host-cmulti))
host-cobjs	:= $(addprefix $(obj)/,$(host-cobjs))
host-cxxmulti	:= $(addprefix $(obj)/,$(host-cxxmulti))
host-cxxobjs	:= $(addprefix $(obj)/,$(host-cxxobjs))

#####
# Handle options to gcc. Support building with separate output directory

_hostc_flags   = $(KBUILD_HOSTCFLAGS)   $(HOST_EXTRACFLAGS)   \
                 $(HOSTCFLAGS_$(target-stem).o)
_hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                 $(HOSTCXXFLAGS_$(target-stem).o)

# $(objtree)/$(obj) for including generated headers from checkin source files
ifeq ($(KBUILD_EXTMOD),)
ifdef building_out_of_srctree
_hostc_flags   += -I $(objtree)/$(obj)
_hostcxx_flags += -I $(objtree)/$(obj)
endif
endif

hostc_flags    = -Wp,-MMD,$(depfile) $(_hostc_flags)
hostcxx_flags  = -Wp,-MMD,$(depfile) $(_hostcxx_flags)

#####
# Compile programs on the host

# Create executable from a single .c file
# host-csingle -> Executable
quiet_cmd_host-csingle 	= HOSTCC  $@
      cmd_host-csingle	= $(HOSTCC) $(hostc_flags) $(KBUILD_HOSTLDFLAGS) -o $@ $< \
		$(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem))
$(host-csingle): $(obj)/%: $(src)/%.c FORCE
	$(call if_changed_dep,host-csingle)

# Link an executable based on list of .o files, all plain c
# host-cmulti -> executable
quiet_cmd_host-cmulti	= HOSTLD  $@
      cmd_host-cmulti	= $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -o $@ \
			  $(addprefix $(obj)/, $($(target-stem)-objs)) \
			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem))
$(host-cmulti): FORCE
	$(call if_changed,host-cmulti)
$(call multi_depend, $(host-cmulti), , -objs)

# Create .o file from a single .c file
# host-cobjs -> .o
quiet_cmd_host-cobjs	= HOSTCC  $@
      cmd_host-cobjs	= $(HOSTCC) $(hostc_flags) -c -o $@ $<
$(host-cobjs): $(obj)/%.o: $(src)/%.c FORCE
	$(call if_changed_dep,host-cobjs)

# Link an executable based on list of .o files, a mixture of .c and .cc
# host-cxxmulti -> executable
quiet_cmd_host-cxxmulti	= HOSTLD  $@
      cmd_host-cxxmulti	= $(HOSTCXX) $(KBUILD_HOSTLDFLAGS) -o $@ \
			  $(foreach o,objs cxxobjs,\
			  $(addprefix $(obj)/, $($(target-stem)-$(o)))) \
			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem))
$(host-cxxmulti): FORCE
	$(call if_changed,host-cxxmulti)
$(call multi_depend, $(host-cxxmulti), , -objs -cxxobjs)

# Create .o file from a single .cc (C++) file
quiet_cmd_host-cxxobjs	= HOSTCXX $@
      cmd_host-cxxobjs	= $(HOSTCXX) $(hostcxx_flags) -c -o $@ $<
$(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
	$(call if_changed_dep,host-cxxobjs)

targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
	   $(host-cxxmulti) $(host-cxxobjs)
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