[PATCH 5.14 059/125] riscv, bpf: Fix potential NULL dereference

[Greg Kroah-Hartman]

From: Björn Töpel <bjorn@xxxxxxxxxx>

commit 27de809a3d83a6199664479ebb19712533d6fd9b upstream.

The bpf_jit_binary_free() function requires a non-NULL argument. When
the RISC-V BPF JIT fails to converge in NR_JIT_ITERATIONS steps,
jit_data->header will be NULL, which triggers a NULL
dereference. Avoid this by checking the argument, prior calling the
function.

Fixes: ca6cb5447cec ("riscv, bpf: Factor common RISC-V JIT code")
Signed-off-by: Björn Töpel <bjorn@xxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211028125115.514587-1-bjorn@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/riscv/net/bpf_jit_core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -125,7 +125,8 @@ struct bpf_prog *bpf_int_jit_compile(str
 
 	if (i == NR_JIT_ITERATIONS) {
 		pr_err("bpf-jit: image did not converge in <%d passes!\n", i);
-		bpf_jit_binary_free(jit_data->header);
+		if (jit_data->header)
+			bpf_jit_binary_free(jit_data->header);
 		prog = orig_prog;
 		goto out_offset;
 	}