diff options
| author | Luke Nelson <lukenels@cs.washington.edu> | 2020-04-22 19:36:30 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-04-25 02:11:46 +0200 |
| commit | 50fe7ebb6475711c15b3397467e6424e20026d94 (patch) | |
| tree | 7148fe1f4e830533d70f313e090b8662ec5497be /kernel/irq_work.c | |
| parent | bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension (diff) | |
| download | linux-50fe7ebb6475711c15b3397467e6424e20026d94.tar.xz linux-50fe7ebb6475711c15b3397467e6424e20026d94.zip | |
bpf, x86_32: Fix clobbering of dst for BPF_JSET
The current JIT clobbers the destination register for BPF_JSET BPF_X
and BPF_K by using "and" and "or" instructions. This is fine when the
destination register is a temporary loaded from a register stored on
the stack but not otherwise.
This patch fixes the problem (for both BPF_K and BPF_X) by always loading
the destination register into temporaries since BPF_JSET should not
modify the destination register.
This bug may not be currently triggerable as BPF_REG_AX is the only
register not stored on the stack and the verifier uses it in a limited
way.
Fixes: 03f5781be2c7b ("bpf, x86_32: add eBPF JIT compiler for ia32")
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Wang YanQing <udknight@gmail.com>
Link: https://lore.kernel.org/bpf/20200422173630.8351-2-luke.r.nels@gmail.com
Diffstat (limited to 'kernel/irq_work.c')
0 files changed, 0 insertions, 0 deletions