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| author | Hari Bathini <[email protected]> | 2021-10-12 12:30:56 +0000 |
|---|---|---|
| committer | Michael Ellerman <[email protected]> | 2021-11-25 00:25:32 +0000 |
| commit | e919c0b2323bedec00e1ecc6280498ff81f59b15 (patch) | |
| tree | e9bbfdc999d8addf95719e740a51a76a69428a7f /arch/powerpc/lib/code-patching.c | |
| parent | bpf ppc32: Add BPF_PROBE_MEM support for JIT (diff) | |
| download | kernel-e919c0b2323bedec00e1ecc6280498ff81f59b15.tar.gz kernel-e919c0b2323bedec00e1ecc6280498ff81f59b15.zip | |
bpf ppc32: Access only if addr is kernel address
With KUAP enabled, any kernel code which wants to access userspace
needs to be surrounded by disable-enable KUAP. But that is not
happening for BPF_PROBE_MEM load instruction. Though PPC32 does not
support read protection, considering the fact that PTR_TO_BTF_ID
(which uses BPF_PROBE_MEM mode) could either be a valid kernel pointer
or NULL but should never be a pointer to userspace address, execute
BPF_PROBE_MEM load only if addr is kernel address, otherwise set
dst_reg=0 and move on.
This will catch NULL, valid or invalid userspace pointers. Only bad
kernel pointer will be handled by BPF exception table.
[Alexei suggested for x86]
Suggested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Hari Bathini <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Diffstat (limited to 'arch/powerpc/lib/code-patching.c')
0 files changed, 0 insertions, 0 deletions