From: Peter Collingbourne <pcc@google.com> mainline inclusion from mainline-v6.12-rc5 commit a552e2ef5fd1a6c78267cd4ec5a9b49aa11bbb1c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB2YVC CVE: CVE-2024-50203 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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/I1496f2bc24fba7a1d492e16e2b94cf4371... Link: https://lore.kernel.org/bpf/20241018221644.3240898-1-pcc@google.com Conflicts: arch/arm64/net/bpf_jit_comp.c [This conflict is due to us not merging a cache optimization commit 96b0f5addc7a ('arm64, bpf: Use bpf_prog_pack for arm64 bpf trampoline')] Signed-off-by: Tengda Wu <wutengda2@huawei.com> --- arch/arm64/net/bpf_jit_comp.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index d6f4aebbad69..76ae4a3131ba 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1949,7 +1949,11 @@ 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); } @@ -1993,7 +1997,11 @@ 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); } -- 2.34.1