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authorDaniel Borkmann <daniel@iogearbox.net>2017-05-02 20:34:54 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-14 13:32:58 +0200
commit6003cc55c1bd15017916c96e08e0b675b7abbc16 (patch)
treee064f5b82e422a42f531390b50ad8d0112c26e8d
parent9150b1040111d3b4ff58e19e298da838064ceaac (diff)
bpf, arm64: fix jit branch offset related to ldimm64
[ Upstream commit ddc665a4bb4b728b4e6ecec8db1b64efa9184b9c ] When the instruction right before the branch destination is a 64 bit load immediate, we currently calculate the wrong jump offset in the ctx->offset[] array as we only account one instruction slot for the 64 bit load immediate although it uses two BPF instructions. Fix it up by setting the offset into the right slot after we incremented the index. Before (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 54ffff82 b.cs 0x00000020 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] After (ldimm64 test 1): [...] 00000020: 52800007 mov w7, #0x0 // #0 00000024: d2800060 mov x0, #0x3 // #3 00000028: d2800041 mov x1, #0x2 // #2 0000002c: eb01001f cmp x0, x1 00000030: 540000a2 b.cs 0x00000044 00000034: d29fffe7 mov x7, #0xffff // #65535 00000038: f2bfffe7 movk x7, #0xffff, lsl #16 0000003c: f2dfffe7 movk x7, #0xffff, lsl #32 00000040: f2ffffe7 movk x7, #0xffff, lsl #48 00000044: d29dddc7 mov x7, #0xeeee // #61166 00000048: f2bdddc7 movk x7, #0xeeee, lsl #16 0000004c: f2ddddc7 movk x7, #0xeeee, lsl #32 00000050: f2fdddc7 movk x7, #0xeeee, lsl #48 [...] Also, add a couple of test cases to make sure JITs pass this test. Tested on Cavium ThunderX ARMv8. The added test cases all pass after the fix. Fixes: 8eee539ddea0 ("arm64: bpf: fix out-of-bounds read in bpf2a64_offset()") Reported-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Xi Wang <xi.wang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/net/bpf_jit_comp.c8
-rw-r--r--lib/test_bpf.c45
2 files changed, 49 insertions, 4 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index b162ad70effc..6297140dd84f 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -728,14 +728,14 @@ static int build_body(struct jit_ctx *ctx)
int ret;
ret = build_insn(insn, ctx);
-
- if (ctx->image == NULL)
- ctx->offset[i] = ctx->idx;
-
if (ret > 0) {
i++;
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
continue;
}
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
if (ret)
return ret;
}
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 10cd1860e5b0..7e26aea3e404 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -4315,6 +4315,51 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 1 } },
},
+ {
+ /* Mainly testing JIT + imm64 here. */
+ "JMP_JGE_X: ldimm64 test 1",
+ .u.insns_int = {
+ BPF_ALU32_IMM(BPF_MOV, R0, 0),
+ BPF_LD_IMM64(R1, 3),
+ BPF_LD_IMM64(R2, 2),
+ BPF_JMP_REG(BPF_JGE, R1, R2, 2),
+ BPF_LD_IMM64(R0, 0xffffffffffffffffUL),
+ BPF_LD_IMM64(R0, 0xeeeeeeeeeeeeeeeeUL),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 0xeeeeeeeeU } },
+ },
+ {
+ "JMP_JGE_X: ldimm64 test 2",
+ .u.insns_int = {
+ BPF_ALU32_IMM(BPF_MOV, R0, 0),
+ BPF_LD_IMM64(R1, 3),
+ BPF_LD_IMM64(R2, 2),
+ BPF_JMP_REG(BPF_JGE, R1, R2, 0),
+ BPF_LD_IMM64(R0, 0xffffffffffffffffUL),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 0xffffffffU } },
+ },
+ {
+ "JMP_JGE_X: ldimm64 test 3",
+ .u.insns_int = {
+ BPF_ALU32_IMM(BPF_MOV, R0, 1),
+ BPF_LD_IMM64(R1, 3),
+ BPF_LD_IMM64(R2, 2),
+ BPF_JMP_REG(BPF_JGE, R1, R2, 4),
+ BPF_LD_IMM64(R0, 0xffffffffffffffffUL),
+ BPF_LD_IMM64(R0, 0xeeeeeeeeeeeeeeeeUL),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, 1 } },
+ },
/* BPF_JMP | BPF_JNE | BPF_X */
{
"JMP_JNE_X: if (3 != 2) return 1",