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| author | Peter Collingbourne <pcc@google.com> | 2024-10-19 01:16:43 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-01 04:02:35 +0300 |
| commit | 7db1a2121f3c7903b8e397392beec563c3d00950 (patch) | |
| tree | f11f4b00f4a21f7641deef96b5f0524c564bba58 /arch/arm64 | |
| parent | 3cd1610c6f1525a040c4fe1e3a894d8af6a201f2 (diff) | |
| download | linux-7db1a2121f3c7903b8e397392beec563c3d00950.tar.xz | |
bpf, arm64: Fix address emission with tag-based KASAN enabled
[ Upstream commit a552e2ef5fd1a6c78267cd4ec5a9b49aa11bbb1c ]
When BPF_TRAMP_F_CALL_ORIG is enabled, the address of a bpf_tramp_image
struct on the stack is passed during the size calculation pass and
an address on the heap is passed during code generation. This may
cause a heap buffer overflow if the heap address is tagged because
emit_a64_mov_i64() will emit longer code than it did during the size
calculation pass. The same problem could occur without tag-based
KASAN if one of the 16-bit words of the stack address happened to
be all-ones during the size calculation pass. Fix the problem by
assuming the worst case (4 instructions) when calculating the size
of the bpf_tramp_image address emission.
Fixes: 19d3c179a377 ("bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG")
Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://linux-review.googlesource.com/id/I1496f2bc24fba7a1d492e16e2b94cf43714f2d3c
Link: https://lore.kernel.org/bpf/20241018221644.3240898-1-pcc@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 59e05a7aea56..6e5a934ee2f5 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -2172,7 +2172,11 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, emit(A64_STR64I(A64_R(20), A64_SP, regs_off + 8), ctx); if (flags & BPF_TRAMP_F_CALL_ORIG) { - emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); + /* for the first pass, assume the worst case */ + if (!ctx->image) + ctx->idx += 4; + else + emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); emit_call((const u64)__bpf_tramp_enter, ctx); } @@ -2216,7 +2220,11 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, if (flags & BPF_TRAMP_F_CALL_ORIG) { im->ip_epilogue = ctx->ro_image + ctx->idx; - emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); + /* for the first pass, assume the worst case */ + if (!ctx->image) + ctx->idx += 4; + else + emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); emit_call((const u64)__bpf_tramp_exit, ctx); } |