[REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure
I am posting these patches for review in the hopes that if I have missed something someone else might catch it. If no issues turn up I intend to merge these patches through my siginfo branch. This set of patches make a few small ABI changes to areas of the linux ABI where as far as I can determine no one cares. - sigqueueinfo in all it's variants now fails if si_signo != sig instead of quietly changing si_signo. The deep issue is that the change happens after the code has already verified in copy_siginfom_from_user that the si_signo and si_code combination is meaningful. - copy_siginfo_from_user now fails if the trailing bytes of siginfo are not 0, when the signal number and si_code combination is not recognized. If the si_signo and si_code combination is recognized we know any trailing bytes are meaningless as the meaningful bytes are in siginfo. This check is to allow people to define new siginfo union members and that will fail on older kernels. The check makes it as safe as possible to have a kernel_siginfo that is smaller than the ABI defined siginfo that the kernel reads from and writes to userspace. The net effect of this change is a kernel that only uses 48 bytes for siginfo internally when the ABI defines siginfo to be 128 bytes. The first EMT_TAGOVF change is not necesssary to strinking siginfo. Eric W. Biederman (6): signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal: Fail sigqueueinfo if si_signo != sig signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Introduce copy_siginfo_from_user and use it's return value signal: Distinguish between kernel_siginfo and siginfo signal: Use a smaller struct siginfo in the kernel arch/alpha/include/uapi/asm/siginfo.h | 1 - arch/arm64/include/uapi/asm/Kbuild | 1 + arch/arm64/include/uapi/asm/siginfo.h | 24 --- arch/ia64/include/uapi/asm/siginfo.h| 2 - arch/mips/include/uapi/asm/siginfo.h| 11 -- arch/parisc/include/uapi/asm/Kbuild | 1 + arch/parisc/include/uapi/asm/siginfo.h | 11 -- arch/powerpc/include/uapi/asm/Kbuild| 1 + arch/powerpc/include/uapi/asm/siginfo.h | 18 --- arch/riscv/include/uapi/asm/Kbuild | 1 + arch/riscv/include/uapi/asm/siginfo.h | 24 --- arch/s390/include/uapi/asm/Kbuild | 1 + arch/s390/include/uapi/asm/siginfo.h| 17 --- arch/sparc/include/uapi/asm/siginfo.h | 7 - arch/x86/include/asm/compat.h | 2 +- arch/x86/include/uapi/asm/siginfo.h | 2 - drivers/usb/core/devio.c| 4 +- fs/binfmt_elf.c | 6 +- fs/coredump.c | 2 +- fs/fcntl.c | 2 +- fs/signalfd.c | 6 +- include/linux/binfmts.h | 2 +- include/linux/compat.h | 4 +- include/linux/coredump.h| 4 +- include/linux/lsm_hooks.h | 4 +- include/linux/posix-timers.h| 2 +- include/linux/ptrace.h | 2 +- include/linux/sched.h | 2 +- include/linux/sched/signal.h| 18 +-- include/linux/security.h| 6 +- include/linux/signal.h | 16 +- include/linux/signal_types.h| 8 +- include/trace/events/signal.h | 4 +- include/uapi/asm-generic/siginfo.h | 193 --- ipc/mqueue.c| 2 +- kernel/ptrace.c | 22 ++- kernel/seccomp.c| 6 +- kernel/signal.c | 263 ++-- kernel/time/posix-timers.c | 2 +- security/apparmor/lsm.c | 2 +- security/security.c | 2 +- security/selinux/hooks.c| 2 +- security/smack/smack_lsm.c | 2 +- 43 files changed, 356 insertions(+), 356 deletions(-) Eric
[REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure
I am posting these patches for review in the hopes that if I have missed something someone else might catch it. If no issues turn up I intend to merge these patches through my siginfo branch. This set of patches make a few small ABI changes to areas of the linux ABI where as far as I can determine no one cares. - sigqueueinfo in all it's variants now fails if si_signo != sig instead of quietly changing si_signo. The deep issue is that the change happens after the code has already verified in copy_siginfom_from_user that the si_signo and si_code combination is meaningful. - copy_siginfo_from_user now fails if the trailing bytes of siginfo are not 0, when the signal number and si_code combination is not recognized. If the si_signo and si_code combination is recognized we know any trailing bytes are meaningless as the meaningful bytes are in siginfo. This check is to allow people to define new siginfo union members and that will fail on older kernels. The check makes it as safe as possible to have a kernel_siginfo that is smaller than the ABI defined siginfo that the kernel reads from and writes to userspace. The net effect of this change is a kernel that only uses 48 bytes for siginfo internally when the ABI defines siginfo to be 128 bytes. The first EMT_TAGOVF change is not necesssary to strinking siginfo. Eric W. Biederman (6): signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal: Fail sigqueueinfo if si_signo != sig signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Introduce copy_siginfo_from_user and use it's return value signal: Distinguish between kernel_siginfo and siginfo signal: Use a smaller struct siginfo in the kernel arch/alpha/include/uapi/asm/siginfo.h | 1 - arch/arm64/include/uapi/asm/Kbuild | 1 + arch/arm64/include/uapi/asm/siginfo.h | 24 --- arch/ia64/include/uapi/asm/siginfo.h| 2 - arch/mips/include/uapi/asm/siginfo.h| 11 -- arch/parisc/include/uapi/asm/Kbuild | 1 + arch/parisc/include/uapi/asm/siginfo.h | 11 -- arch/powerpc/include/uapi/asm/Kbuild| 1 + arch/powerpc/include/uapi/asm/siginfo.h | 18 --- arch/riscv/include/uapi/asm/Kbuild | 1 + arch/riscv/include/uapi/asm/siginfo.h | 24 --- arch/s390/include/uapi/asm/Kbuild | 1 + arch/s390/include/uapi/asm/siginfo.h| 17 --- arch/sparc/include/uapi/asm/siginfo.h | 7 - arch/x86/include/asm/compat.h | 2 +- arch/x86/include/uapi/asm/siginfo.h | 2 - drivers/usb/core/devio.c| 4 +- fs/binfmt_elf.c | 6 +- fs/coredump.c | 2 +- fs/fcntl.c | 2 +- fs/signalfd.c | 6 +- include/linux/binfmts.h | 2 +- include/linux/compat.h | 4 +- include/linux/coredump.h| 4 +- include/linux/lsm_hooks.h | 4 +- include/linux/posix-timers.h| 2 +- include/linux/ptrace.h | 2 +- include/linux/sched.h | 2 +- include/linux/sched/signal.h| 18 +-- include/linux/security.h| 6 +- include/linux/signal.h | 16 +- include/linux/signal_types.h| 8 +- include/trace/events/signal.h | 4 +- include/uapi/asm-generic/siginfo.h | 193 --- ipc/mqueue.c| 2 +- kernel/ptrace.c | 22 ++- kernel/seccomp.c| 6 +- kernel/signal.c | 263 ++-- kernel/time/posix-timers.c | 2 +- security/apparmor/lsm.c | 2 +- security/security.c | 2 +- security/selinux/hooks.c| 2 +- security/smack/smack_lsm.c | 2 +- 43 files changed, 356 insertions(+), 356 deletions(-) Eric
