diff options
| author | Peter Collingbourne <pcc@google.com> | 2024-10-18 15:16:43 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-22 14:12:25 +0200 |
| commit | f521c2a0c0c4585f36d912bf62c852b88682c4f2 (patch) | |
| tree | e1bf3e133451d902d214d4086f36bd4abf33f1c7 /arch | |
| parent | d9664e6ff040798a46cdc5d401064f55b8676c83 (diff) | |
| download | linux-f521c2a0c0c4585f36d912bf62c852b88682c4f2.tar.gz linux-f521c2a0c0c4585f36d912bf62c852b88682c4f2.tar.bz2 linux-f521c2a0c0c4585f36d912bf62c852b88682c4f2.zip | |
bpf, arm64: Fix address emission with tag-based KASAN enabled
commit a552e2ef5fd1a6c78267cd4ec5a9b49aa11bbb1c upstream.
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
[Minor context change fixed.]
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -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 0fe012f9b1b6..d8012d1a2e15 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -2001,7 +2001,11 @@ 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); } @@ -2045,7 +2049,11 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, if (flags & BPF_TRAMP_F_CALL_ORIG) { im->ip_epilogue = ctx->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); } |