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authorAlexei Starovoitov2018-01-12 18:59:52 -0800
committerDaniel Borkmann2018-01-14 23:05:33 +0100
commit68fda450a7df51cff9e5a4d4a4d9d0d5f2589153 (patch)
tree555aa6473c3d960c0a95bd9c4843c8b48947cf1f /net
parentc366287ebd698ef5e3de300d90cd62ee9ee7373e (diff)
bpf: fix 32-bit divide by zero
due to some JITs doing if (src_reg == 0) check in 64-bit mode for div/mod operations mask upper 32-bits of src register before doing the check Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT") Fixes: 7a12b5031c6b ("sparc64: Add eBPF JIT.") Reported-by: syzbot+48340bb518e88849e2e3@syzkaller.appspotmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index d339ef170df6..1c0eb436671f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -458,6 +458,10 @@ do_pass:
convert_bpf_extensions(fp, &insn))
break;
+ if (fp->code == (BPF_ALU | BPF_DIV | BPF_X) ||
+ fp->code == (BPF_ALU | BPF_MOD | BPF_X))
+ *insn++ = BPF_MOV32_REG(BPF_REG_X, BPF_REG_X);
+
*insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
break;