From: Puranjay Mohan puranjay@kernel.org
[ Upstream commit 19d3c179a37730caf600a97fed3794feac2b197b ]
When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls __bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them the struct bpf_tramp_image *im pointer as an argument in R0.
The trampoline generation code uses emit_addr_mov_i64() to emit instructions for moving the bpf_tramp_image address into R0, but emit_addr_mov_i64() assumes the address to be in the vmalloc() space and uses only 48 bits. Because bpf_tramp_image is allocated using kzalloc(), its address can use more than 48-bits, in this case the trampoline will pass an invalid address to __bpf_tramp_enter/exit() causing a kernel crash.
Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64() as it can work with addresses that are greater than 48-bits.
Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64") Signed-off-by: Puranjay Mohan puranjay@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Closes: https://lore.kernel.org/all/SJ0PR15MB461564D3F7E7A763498CA6A8CBDB2@SJ0PR15MB... Link: https://lore.kernel.org/bpf/20240711151838.43469-1-puranjay@kernel.org [Minor context change fixed.] Signed-off-by: Bin Lan bin.lan.cn@windriver.com Signed-off-by: He Zhe zhe.he@windriver.com --- Build test passed. --- arch/arm64/net/bpf_jit_comp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 5074bd1d37b5..7c5156e7d31e 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1952,7 +1952,7 @@ 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_addr_mov_i64(A64_R(0), (const u64)im, ctx); + emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); emit_call((const u64)__bpf_tramp_enter, ctx); }
@@ -1996,7 +1996,7 @@ 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_addr_mov_i64(A64_R(0), (const u64)im, ctx); + emit_a64_mov_i64(A64_R(0), (const u64)im, ctx); emit_call((const u64)__bpf_tramp_exit, ctx); }