linux/arch/powerpc
Nicholas Piggin f35d2f249e powerpc/64s: Fix copy-paste data exposure into newly created tasks
copy-paste contains implicit "copy buffer" state that can contain
arbitrary user data (if the user process executes a copy instruction).
This could be snooped by another process if a context switch hits while
the state is live. So cp_abort is executed on context switch to clear
out possible sensitive data and prevent the leak.

cp_abort is done after the low level _switch(), which means it is never
reached by newly created tasks, so they could snoop on this buffer
between their first and second context switch.

Fix this by doing the cp_abort before calling _switch. Add some
comments which should make the issue harder to miss.

Fixes: 07d2a628bc ("powerpc/64s: Avoid cpabort in context switch when possible")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622053036.474678-1-npiggin@gmail.com
2021-06-25 00:07:11 +10:00
..
boot powerpc/boot: Add a boot wrapper for Microwatt 2021-06-21 21:16:32 +10:00
configs powerpc/microwatt: Add microwatt_defconfig 2021-06-21 21:16:32 +10:00
crypto crypto: powepc/sha1 - remove unneeded semicolon 2021-03-07 15:13:14 +11:00
include powerpc: Remove klimit 2021-06-25 00:07:10 +10:00
kernel powerpc/64s: Fix copy-paste data exposure into newly created tasks 2021-06-25 00:07:11 +10:00
kexec powerpc/kexec_file: Use current CPU info while setting up FDT 2021-05-04 22:26:57 +10:00
kvm powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
lib powerpc/64: use interrupt restart table to speed up return from interrupt 2021-06-25 00:06:56 +10:00
math-emu powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
mm powerpc/mm: Properly coalesce pages in ptdump 2021-06-25 00:07:10 +10:00
net powerpc/bpf: Write protect JIT code 2021-06-21 21:13:21 +10:00
perf powerpc: make stack walking KASAN-safe 2021-06-17 00:09:11 +10:00
platforms powerpc: Remove klimit 2021-06-25 00:07:10 +10:00
purgatory powerpc/kexec: Don't use .machine ppc64 in trampoline_64.S 2021-04-08 21:17:43 +10:00
sysdev powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
tools powerpc/tools: Remove 90 line limit in checkpatch script 2020-09-08 22:57:11 +10:00
xmon powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
Kbuild powerpc/kexec: Move kexec files into a dedicated subdir. 2019-11-21 15:41:34 +11:00
Kconfig powerpc: Add Microwatt platform 2021-06-21 21:15:26 +10:00
Kconfig.debug powerpc: Make PPC_IRQ_SOFT_MASK_DEBUG depend on PPC64 2021-06-25 00:07:09 +10:00
Makefile powerpc/Makefile: Add ppc32/ppc64_randconfig targets 2021-05-23 20:51:35 +10:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00