Revision 0620fddb56dfaf0e1034eeb69d79c73b361debbf authored by Eric Biggers on 08 June 2017, 13:49:26 UTC, committed by James Morris on 09 June 2017, 03:29:48 UTC
While a 'struct key' itself normally does not contain sensitive
information, Documentation/security/keys.txt actually encourages this:
"Having a payload is not required; and the payload can, in fact,
just be a value stored in the struct key itself."
In case someone has taken this advice, or will take this advice in the
future, zero the key structure before freeing it. We might as well, and
as a bonus this could make it a bit more difficult for an adversary to
determine which keys have recently been in use.
This is safe because the key_jar cache does not use a constructor.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
1 parent ee618b4
Kbuild
#
# Kbuild for top-level directory of the kernel
# This file takes care of the following:
# 1) Generate bounds.h
# 2) Generate timeconst.h
# 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
# 4) Check for missing system calls
# 5) Generate constants.py (may need bounds.h)
#####
# 1) Generate bounds.h
bounds-file := include/generated/bounds.h
always := $(bounds-file)
targets := kernel/bounds.s
# We use internal kbuild rules to avoid the "is up to date" message from make
kernel/bounds.s: kernel/bounds.c FORCE
$(Q)mkdir -p $(dir $@)
$(call if_changed_dep,cc_s_c)
$(obj)/$(bounds-file): kernel/bounds.s FORCE
$(call filechk,offsets,__LINUX_BOUNDS_H__)
#####
# 2) Generate timeconst.h
timeconst-file := include/generated/timeconst.h
targets += $(timeconst-file)
quiet_cmd_gentimeconst = GEN $@
define cmd_gentimeconst
(echo $(CONFIG_HZ) | bc -q $< ) > $@
endef
define filechk_gentimeconst
(echo $(CONFIG_HZ) | bc -q $< )
endef
$(obj)/$(timeconst-file): kernel/time/timeconst.bc FORCE
$(call filechk,gentimeconst)
#####
# 3) Generate asm-offsets.h
#
offsets-file := include/generated/asm-offsets.h
always += $(offsets-file)
targets += arch/$(SRCARCH)/kernel/asm-offsets.s
# We use internal kbuild rules to avoid the "is up to date" message from make
arch/$(SRCARCH)/kernel/asm-offsets.s: arch/$(SRCARCH)/kernel/asm-offsets.c \
$(obj)/$(timeconst-file) $(obj)/$(bounds-file) FORCE
$(Q)mkdir -p $(dir $@)
$(call if_changed_dep,cc_s_c)
$(obj)/$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
$(call filechk,offsets,__ASM_OFFSETS_H__)
#####
# 4) Check for missing system calls
#
always += missing-syscalls
targets += missing-syscalls
quiet_cmd_syscalls = CALL $<
cmd_syscalls = $(CONFIG_SHELL) $< $(CC) $(c_flags) $(missing_syscalls_flags)
missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
$(call cmd,syscalls)
#####
# 5) Generate constants for Python GDB integration
#
extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py
build_constants_py: $(obj)/$(timeconst-file) $(obj)/$(bounds-file)
@$(MAKE) $(build)=scripts/gdb/linux $@
# Keep these three files during make clean
no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)
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