From: Colin Ian King colin.king@canonical.com
[ Upstream commit 91091656252f5d6d8c476e0c92776ce9fae7b445 ]
Currently array jit->seen_reg[r1] is being accessed before the range checking of index r1. The range changing on r1 should be performed first since it will avoid any potential out-of-range accesses on the array seen_reg[] and also it is more optimal to perform checks on r1 before fetching data from the array. Fix this by swapping the order of the checks before the array access.
Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Tested-by: Ilya Leoshkevich iii@linux.ibm.com Acked-by: Ilya Leoshkevich iii@linux.ibm.com Link: https://lore.kernel.org/bpf/20210715125712.24690-1-colin.king@canonical.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index b8bd84104843..bb3710e7ad9c 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -117,7 +117,7 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) { u32 r1 = reg2hex[b1];
- if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15) + if (r1 >= 6 && r1 <= 15 && !jit->seen_reg[r1]) jit->seen_reg[r1] = 1; }