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05 April 2024, 19:05:47 UTC
Revision d3b6372c5881cb54925212abb62c521df8ba4809 authored by Juergen Gross on 07 March 2022, 08:48:54 UTC, committed by Juergen Gross on 07 March 2022, 08:48:54 UTC 
xen/gntalloc: don't use gnttab_query_foreign_access()
 
Using gnttab_query_foreign_access() is unsafe, as it is racy by design.

The use case in the gntalloc driver is not needed at all. While at it
replace the call of gnttab_end_foreign_access_ref() with a call of
gnttab_end_foreign_access(), which is what is really wanted there. In
case the grant wasn't used due to an allocation failure, just free the
grant via gnttab_free_grant_reference().

This is CVE-2022-23039 / part of XSA-396.

Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V3:
- fix __del_gref() (Jan Beulich)
1 parent 33172ab
Raw File
Tip revision: d3b6372c5881cb54925212abb62c521df8ba4809 authored by Juergen Gross on 07 March 2022, 08:48:54 UTC
xen/gntalloc: don't use gnttab_query_foreign_access()
Tip revision: d3b6372
Kbuild 
# SPDX-License-Identifier: GPL-2.0
#
# Kbuild for top-level directory of the kernel

#####
# Generate bounds.h

bounds-file := include/generated/bounds.h

always-y := $(bounds-file)
targets := kernel/bounds.s

$(bounds-file): kernel/bounds.s FORCE
	$(call filechk,offsets,__LINUX_BOUNDS_H__)

#####
# Generate timeconst.h

timeconst-file := include/generated/timeconst.h

filechk_gentimeconst = echo $(CONFIG_HZ) | bc -q $<

$(timeconst-file): kernel/time/timeconst.bc FORCE
	$(call filechk,gentimeconst)

#####
# Generate asm-offsets.h

offsets-file := include/generated/asm-offsets.h

always-y += $(offsets-file)
targets += arch/$(SRCARCH)/kernel/asm-offsets.s

arch/$(SRCARCH)/kernel/asm-offsets.s: $(timeconst-file) $(bounds-file)

$(offsets-file): arch/$(SRCARCH)/kernel/asm-offsets.s FORCE
	$(call filechk,offsets,__ASM_OFFSETS_H__)

#####
# Check for missing system calls

always-y += 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)

#####
# Check atomic headers are up-to-date

always-y += old-atomics

quiet_cmd_atomics = CALL    $<
      cmd_atomics = $(CONFIG_SHELL) $<

old-atomics: scripts/atomic/check-atomics.sh FORCE
	$(call cmd,atomics)
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