In arm64, kernelspace address accessors cannot be used to access
userspace addresses, which means bpf_probe_read{,str}() cannot access
userspace addresses. That causes e.g. command-line parameters to not
appear when snooping execve using bpf.
This patch series takes the upstream solution. This solution also
changes user API in the following ways:
* Add probe_read_{user, kernel}{,_str} bpf helpers
* Add skb_output helper to the enum only (calling it not supported)
* Add support for %pks, %pus specifiers
An alternative fix only takes the required logic to existing API without
adding new API, was suggested here:
https://www.spinics.net/lists/stable/msg454945.html
Another option is to only take patches [1-4] of this patchset, and add
on top of them commit 8d92db5c04d1 ("bpf: rework the compat kernel probe
handling"). In that case, the last patch would require function renames
and conflict resolutions that were avoided in this patchset by pulling
patches [5-7].
Christoph Hellwig (3):
maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
maccess: rename strncpy_from_unsafe_strict to
strncpy_from_kernel_nofault
bpf: rework the compat kernel probe handling
Daniel Borkmann (4):
uaccess: Add strict non-pagefault kernel-space read function
bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str
helpers
bpf: Restrict bpf_probe_read{, str}() only to archs where they work
bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus
specifier
Petr Mladek (1):
powerpc/bpf: Enable bpf_probe_read{, str}() on powerpc again
Documentation/core-api/printk-formats.rst | 14 +
arch/arm/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/x86/Kconfig | 1 +
arch/x86/mm/Makefile | 2 +-
arch/x86/mm/maccess.c | 43 +++
include/linux/uaccess.h | 8 +-
include/uapi/linux/bpf.h | 123 ++++++---
init/Kconfig | 3 +
kernel/trace/bpf_trace.c | 302 ++++++++++++++++------
kernel/trace/trace_kprobe.c | 2 +-
lib/vsprintf.c | 12 +
mm/maccess.c | 48 +++-
tools/include/uapi/linux/bpf.h | 116 ++++++---
15 files changed, 512 insertions(+), 165 deletions(-)
create mode 100644 arch/x86/mm/maccess.c
--
2.25.1
