From: Eric Biggers <[email protected]> This is a second attempt to fix the bug found by syzkaller where the ptrace syscall can be used to set invalid bits in a task's FPU state. I also found that an equivalent bug was reachable using the sigreturn syscall, so the first patch fixes the bug in both cases.
The other two patches start validating the other parts of the xstate_header and make it so that invalid FPU states can no longer be abused to leak the FPU registers of other processes. Eric Biggers (3): x86/fpu: don't let userspace set bogus xcomp_bv x86/fpu: tighten validation of user-supplied xstate_header x86/fpu: reinitialize FPU registers if restoring FPU state fails arch/x86/include/asm/fpu/internal.h | 29 ++++++++++++++++++++--------- arch/x86/include/asm/fpu/xstate.h | 19 +++++++++++++++++++ arch/x86/kernel/fpu/core.c | 16 ++++++++++++++++ arch/x86/kernel/fpu/regset.c | 20 +++++++++----------- arch/x86/kernel/fpu/signal.c | 15 +++++++++++---- arch/x86/kernel/fpu/xstate.c | 27 ++++++++++----------------- 6 files changed, 85 insertions(+), 41 deletions(-) -- 2.14.1.690.gbb1197296e-goog
