diff options
| -rw-r--r-- | include/linux/bpf_verifier.h | 2 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 85 |
2 files changed, 44 insertions, 43 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 2e20207315a9..8458632824a4 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -24,7 +24,7 @@ */ #define TMP_STR_BUF_LEN 320 /* Patch buffer size */ -#define INSN_BUF_SIZE 16 +#define INSN_BUF_SIZE 32 /* Liveness marks, used for registers and spilled-regs (in stack slots). * Read marks propagate upwards until they find a write mark; they record that diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 217eb0eafa2a..b806afeba212 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19800,7 +19800,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) * least one ctx ptr saving insn before the * epilogue. */ - epilogue_idx = i + delta; + epilogue_idx = i + delta; } goto patch_insn_buf; } else { @@ -21232,7 +21232,7 @@ static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env, int position, s32 stack_base, u32 callback_subprogno, - u32 *cnt) + u32 *total_cnt) { s32 r6_offset = stack_base + 0 * BPF_REG_SIZE; s32 r7_offset = stack_base + 1 * BPF_REG_SIZE; @@ -21241,55 +21241,56 @@ static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env, int reg_loop_cnt = BPF_REG_7; int reg_loop_ctx = BPF_REG_8; + struct bpf_insn *insn_buf = env->insn_buf; struct bpf_prog *new_prog; u32 callback_start; u32 call_insn_offset; s32 callback_offset; + u32 cnt = 0; /* This represents an inlined version of bpf_iter.c:bpf_loop, * be careful to modify this code in sync. */ - struct bpf_insn insn_buf[] = { - /* Return error and jump to the end of the patch if - * expected number of iterations is too big. - */ - BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2), - BPF_MOV32_IMM(BPF_REG_0, -E2BIG), - BPF_JMP_IMM(BPF_JA, 0, 0, 16), - /* spill R6, R7, R8 to use these as loop vars */ - BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset), - BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset), - BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset), - /* initialize loop vars */ - BPF_MOV64_REG(reg_loop_max, BPF_REG_1), - BPF_MOV32_IMM(reg_loop_cnt, 0), - BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3), - /* loop header, - * if reg_loop_cnt >= reg_loop_max skip the loop body - */ - BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5), - /* callback call, - * correct callback offset would be set after patching - */ - BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt), - BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx), - BPF_CALL_REL(0), - /* increment loop counter */ - BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1), - /* jump to loop header if callback returned 0 */ - BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6), - /* return value of bpf_loop, - * set R0 to the number of iterations - */ - BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt), - /* restore original values of R6, R7, R8 */ - BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset), - BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset), - BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset), - }; - *cnt = ARRAY_SIZE(insn_buf); - new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt); + /* Return error and jump to the end of the patch if + * expected number of iterations is too big. + */ + insn_buf[cnt++] = BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2); + insn_buf[cnt++] = BPF_MOV32_IMM(BPF_REG_0, -E2BIG); + insn_buf[cnt++] = BPF_JMP_IMM(BPF_JA, 0, 0, 16); + /* spill R6, R7, R8 to use these as loop vars */ + insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset); + insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset); + insn_buf[cnt++] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset); + /* initialize loop vars */ + insn_buf[cnt++] = BPF_MOV64_REG(reg_loop_max, BPF_REG_1); + insn_buf[cnt++] = BPF_MOV32_IMM(reg_loop_cnt, 0); + insn_buf[cnt++] = BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3); + /* loop header, + * if reg_loop_cnt >= reg_loop_max skip the loop body + */ + insn_buf[cnt++] = BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5); + /* callback call, + * correct callback offset would be set after patching + */ + insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt); + insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx); + insn_buf[cnt++] = BPF_CALL_REL(0); + /* increment loop counter */ + insn_buf[cnt++] = BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1); + /* jump to loop header if callback returned 0 */ + insn_buf[cnt++] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6); + /* return value of bpf_loop, + * set R0 to the number of iterations + */ + insn_buf[cnt++] = BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt); + /* restore original values of R6, R7, R8 */ + insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset); + insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset); + insn_buf[cnt++] = BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset); + + *total_cnt = cnt; + new_prog = bpf_patch_insn_data(env, position, insn_buf, cnt); if (!new_prog) return new_prog; |