From: Daniel Borkmann <daniel@xxxxxxxxxxxxx> commit b4e76f7e6d3200462c6354a6ad4ae167459e61f8 upstream. Dan Carpenter reported [1] a static checker warning that ctx->offsets[] may be accessed off by one from build_body(), since it's allocated with fp->len * sizeof(*ctx.offsets) as length. The cBPF arm and ppc code doesn't have this issue as claimed, so only mips seems to be affected and should like most other JITs allocate with fp->len + 1. A few number of JITs (x86, sparc, arm64) handle this differently, where they only require fp->len array elements. [1] http://www.spinics.net/lists/mips/msg64193.html Fixes: c6610de353da ("MIPS: net: Add BPF JIT") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: ast@xxxxxxxxxx Cc: linux-mips@xxxxxxxxxxxxxx Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/13814/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/net/bpf_jit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/net/bpf_jit.c +++ b/arch/mips/net/bpf_jit.c @@ -1207,7 +1207,7 @@ void bpf_jit_compile(struct bpf_prog *fp memset(&ctx, 0, sizeof(ctx)); - ctx.offsets = kcalloc(fp->len, sizeof(*ctx.offsets), GFP_KERNEL); + ctx.offsets = kcalloc(fp->len + 1, sizeof(*ctx.offsets), GFP_KERNEL); if (ctx.offsets == NULL) return; Patches currently in stable-queue which might be from daniel@xxxxxxxxxxxxx are queue-4.4/bpf-mips-fix-off-by-one-in-ctx-offset-allocation.patch
