From fce366a9dd0ddc47e7ce05611c266e8574a45116 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 31 Mar 2017 02:24:02 +0200 Subject: [PATCH 1/3] bpf, verifier: fix alu ops against map_value{, _adj} register types While looking into map_value_adj, I noticed that alu operations directly on the map_value() resp. map_value_adj() register (any alu operation on a map_value() register will turn it into a map_value_adj() typed register) are not sufficiently protected against some of the operations. Two non-exhaustive examples are provided that the verifier needs to reject: i) BPF_AND on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0xbf842a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+2 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (57) r0 &= 8 8: (7a) *(u64 *)(r0 +0) = 22 R0=map_value_adj(ks=8,vs=48,id=0),min_value=0,max_value=8 R10=fp 9: (95) exit from 6 to 9: R0=inv,min_value=0,max_value=0 R10=fp 9: (95) exit processed 10 insns ii) BPF_ADD in 32 bit mode on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0xc24eee00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+2 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (04) (u32) r0 += (u32) 0 8: (7a) *(u64 *)(r0 +0) = 22 R0=map_value_adj(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 9: (95) exit from 6 to 9: R0=inv,min_value=0,max_value=0 R10=fp 9: (95) exit processed 10 insns Issue is, while min_value / max_value boundaries for the access are adjusted appropriately, we change the pointer value in a way that cannot be sufficiently tracked anymore from its origin. Operations like BPF_{AND,OR,DIV,MUL,etc} on a destination register that is PTR_TO_MAP_VALUE{,_ADJ} was probably unintended, in fact, all the test cases coming with 484611357c19 ("bpf: allow access into map value arrays") perform BPF_ADD only on the destination register that is PTR_TO_MAP_VALUE_ADJ. Only for UNKNOWN_VALUE register types such operations make sense, f.e. with unknown memory content fetched initially from a constant offset from the map value memory into a register. That register is then later tested against lower / upper bounds, so that the verifier can then do the tracking of min_value / max_value, and properly check once that UNKNOWN_VALUE register is added to the destination register with type PTR_TO_MAP_VALUE{,_ADJ}. This is also what the original use-case is solving. Note, tracking on what is being added is done through adjust_reg_min_max_vals() and later access to the map value enforced with these boundaries and the given offset from the insn through check_map_access_adj(). Tests will fail for non-root environment due to prohibited pointer arithmetic, in particular in check_alu_op(), we bail out on the is_pointer_value() check on the dst_reg (which is false in root case as we allow for pointer arithmetic via env->allow_ptr_leaks). Similarly to PTR_TO_PACKET, one way to fix it is to restrict the allowed operations on PTR_TO_MAP_VALUE{,_ADJ} registers to 64 bit mode BPF_ADD. The test_verifier suite runs fine after the patch and it also rejects mentioned test cases. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Daniel Borkmann Reviewed-by: Josef Bacik Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5e6202e62265f..86deddecff254 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1925,6 +1925,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) * register as unknown. */ if (env->allow_ptr_leaks && + BPF_CLASS(insn->code) == BPF_ALU64 && opcode == BPF_ADD && (dst_reg->type == PTR_TO_MAP_VALUE || dst_reg->type == PTR_TO_MAP_VALUE_ADJ)) dst_reg->type = PTR_TO_MAP_VALUE_ADJ; From 79adffcd6489ef43bda2dfded3d637d7fb4fac80 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 31 Mar 2017 02:24:03 +0200 Subject: [PATCH 2/3] bpf, verifier: fix rejection of unaligned access checks for map_value_adj Currently, the verifier doesn't reject unaligned access for map_value_adj register types. Commit 484611357c19 ("bpf: allow access into map value arrays") added logic to check_ptr_alignment() extending it from PTR_TO_PACKET to also PTR_TO_MAP_VALUE_ADJ, but for PTR_TO_MAP_VALUE_ADJ no enforcement is in place, because reg->id for PTR_TO_MAP_VALUE_ADJ reg types is never non-zero, meaning, we can cause BPF_H/_W/_DW-based unaligned access for architectures not supporting efficient unaligned access, and thus worst case could raise exceptions on some archs that are unable to correct the unaligned access or perform a different memory access to the actual requested one and such. i) Unaligned load with !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0x42533a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+11 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (61) r1 = *(u32 *)(r0 +0) 8: (35) if r1 >= 0xb goto pc+9 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R1=inv,min_value=0,max_value=10 R10=fp 9: (07) r0 += 3 10: (79) r7 = *(u64 *)(r0 +0) R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R1=inv,min_value=0,max_value=10 R10=fp 11: (79) r7 = *(u64 *)(r0 +2) R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R1=inv,min_value=0,max_value=10 R7=inv R10=fp [...] ii) Unaligned store with !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0x4df16a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+19 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (07) r0 += 3 8: (7a) *(u64 *)(r0 +0) = 42 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp 9: (7a) *(u64 *)(r0 +2) = 43 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp 10: (7a) *(u64 *)(r0 -2) = 44 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp [...] For the PTR_TO_PACKET type, reg->id is initially zero when skb->data was fetched, it later receives a reg->id from env->id_gen generator once another register with UNKNOWN_VALUE type was added to it via check_packet_ptr_add(). The purpose of this reg->id is twofold: i) it is used in find_good_pkt_pointers() for setting the allowed access range for regs with PTR_TO_PACKET of same id once verifier matched on data/data_end tests, and ii) for check_ptr_alignment() to determine that when not having efficient unaligned access and register with UNKNOWN_VALUE was added to PTR_TO_PACKET, that we're only allowed to access the content bytewise due to unknown unalignment. reg->id was never intended for PTR_TO_MAP_VALUE{,_ADJ} types and thus is always zero, the only marking is in PTR_TO_MAP_VALUE_OR_NULL that was added after 484611357c19 via 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers"). Above tests will fail for non-root environment due to prohibited pointer arithmetic. The fix splits register-type specific checks into their own helper instead of keeping them combined, so we don't run into a similar issue in future once we extend check_ptr_alignment() further and forget to add reg->type checks for some of the checks. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Daniel Borkmann Reviewed-by: Josef Bacik Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 58 ++++++++++++++++++++++++++++--------------- 1 file changed, 38 insertions(+), 20 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 86deddecff254..a834068a400e2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -765,38 +765,56 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno) } } -static int check_ptr_alignment(struct bpf_verifier_env *env, - struct bpf_reg_state *reg, int off, int size) +static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, + int off, int size) { - if (reg->type != PTR_TO_PACKET && reg->type != PTR_TO_MAP_VALUE_ADJ) { - if (off % size != 0) { - verbose("misaligned access off %d size %d\n", - off, size); - return -EACCES; - } else { - return 0; - } - } - - if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) - /* misaligned access to packet is ok on x86,arm,arm64 */ - return 0; - if (reg->id && size != 1) { - verbose("Unknown packet alignment. Only byte-sized access allowed\n"); + verbose("Unknown alignment. Only byte-sized access allowed in packet access.\n"); return -EACCES; } /* skb->data is NET_IP_ALIGN-ed */ - if (reg->type == PTR_TO_PACKET && - (NET_IP_ALIGN + reg->off + off) % size != 0) { + if ((NET_IP_ALIGN + reg->off + off) % size != 0) { verbose("misaligned packet access off %d+%d+%d size %d\n", NET_IP_ALIGN, reg->off, off, size); return -EACCES; } + return 0; } +static int check_val_ptr_alignment(const struct bpf_reg_state *reg, + int size) +{ + if (size != 1) { + verbose("Unknown alignment. Only byte-sized access allowed in value access.\n"); + return -EACCES; + } + + return 0; +} + +static int check_ptr_alignment(const struct bpf_reg_state *reg, + int off, int size) +{ + switch (reg->type) { + case PTR_TO_PACKET: + return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 : + check_pkt_ptr_alignment(reg, off, size); + case PTR_TO_MAP_VALUE_ADJ: + return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 : + check_val_ptr_alignment(reg, size); + default: + if (off % size != 0) { + verbose("misaligned access off %d size %d\n", + off, size); + return -EACCES; + } + + return 0; + } +} + /* check whether memory at (regno + off) is accessible for t = (read | write) * if t==write, value_regno is a register which value is stored into memory * if t==read, value_regno is a register which will receive the value from memory @@ -818,7 +836,7 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, if (size < 0) return size; - err = check_ptr_alignment(env, reg, off, size); + err = check_ptr_alignment(reg, off, size); if (err) return err; From 02ea80b1850e48abbce77878896229d7cc5cb230 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 31 Mar 2017 02:24:04 +0200 Subject: [PATCH 3/3] bpf: add various verifier test cases for self-tests Add a couple of test cases, for example, probing for xadd on a spilled pointer to packet and map_value_adj register, various other map_value_adj tests including the unaligned load/store, and trying out pointer arithmetic on map_value_adj register itself. For the unaligned load/store, we need to figure out whether the architecture has efficient unaligned access and need to mark affected tests accordingly. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- tools/include/linux/filter.h | 10 + tools/testing/selftests/bpf/Makefile | 9 +- tools/testing/selftests/bpf/test_verifier.c | 270 +++++++++++++++++++- 3 files changed, 283 insertions(+), 6 deletions(-) diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h index 122153b16ea4e..390d7c9685fd6 100644 --- a/tools/include/linux/filter.h +++ b/tools/include/linux/filter.h @@ -168,6 +168,16 @@ .off = OFF, \ .imm = 0 }) +/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */ + +#define BPF_STX_XADD(SIZE, DST, SRC, OFF) \ + ((struct bpf_insn) { \ + .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \ + .dst_reg = DST, \ + .src_reg = SRC, \ + .off = OFF, \ + .imm = 0 }) + /* Memory store, *(uint *) (dst_reg + off16) = imm32 */ #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \ diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 6a1ad58cb66f4..9af09e8099c0a 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -1,7 +1,14 @@ LIBDIR := ../../../lib BPFDIR := $(LIBDIR)/bpf +APIDIR := ../../../include/uapi +GENDIR := ../../../../include/generated +GENHDR := $(GENDIR)/autoconf.h -CFLAGS += -Wall -O2 -I../../../include/uapi -I$(LIBDIR) +ifneq ($(wildcard $(GENHDR)),) + GENFLAGS := -DHAVE_GENHDR +endif + +CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) LDLIBS += -lcap TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 7d761d4cc7590..c848e90b64213 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -30,6 +30,14 @@ #include +#ifdef HAVE_GENHDR +# include "autoconf.h" +#else +# if defined(__i386) || defined(__x86_64) || defined(__s390x__) || defined(__aarch64__) +# define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 1 +# endif +#endif + #include "../../../include/linux/filter.h" #ifndef ARRAY_SIZE @@ -39,6 +47,8 @@ #define MAX_INSNS 512 #define MAX_FIXUPS 8 +#define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS (1 << 0) + struct bpf_test { const char *descr; struct bpf_insn insns[MAX_INSNS]; @@ -53,6 +63,7 @@ struct bpf_test { REJECT } result, result_unpriv; enum bpf_prog_type prog_type; + uint8_t flags; }; /* Note we want this to be 64 bit aligned so that the end of our array is @@ -2431,6 +2442,30 @@ static struct bpf_test tests[] = { .result = ACCEPT, .prog_type = BPF_PROG_TYPE_SCHED_CLS, }, + { + "direct packet access: test15 (spill with xadd)", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct __sk_buff, data)), + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, + offsetof(struct __sk_buff, data_end)), + BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8), + BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 8), + BPF_MOV64_IMM(BPF_REG_5, 4096), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_4, BPF_REG_2, 0), + BPF_STX_XADD(BPF_DW, BPF_REG_4, BPF_REG_5, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_4, 0), + BPF_STX_MEM(BPF_W, BPF_REG_2, BPF_REG_5, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .errstr = "R2 invalid mem access 'inv'", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + }, { "helper access to packet: test1, valid packet_ptr range", .insns = { @@ -2934,6 +2969,7 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R0 pointer arithmetic prohibited", .result_unpriv = REJECT, .result = ACCEPT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "valid map access into an array with a variable", @@ -2957,6 +2993,7 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R0 pointer arithmetic prohibited", .result_unpriv = REJECT, .result = ACCEPT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "valid map access into an array with a signed variable", @@ -2984,6 +3021,7 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R0 pointer arithmetic prohibited", .result_unpriv = REJECT, .result = ACCEPT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid map access into an array with a constant", @@ -3025,6 +3063,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is outside of the array range", .result_unpriv = REJECT, .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid map access into an array with a variable", @@ -3048,6 +3087,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.", .result_unpriv = REJECT, .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid map access into an array with no floor check", @@ -3074,6 +3114,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.", .result_unpriv = REJECT, .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid map access into an array with a invalid max check", @@ -3100,6 +3141,7 @@ static struct bpf_test tests[] = { .errstr = "invalid access to map value, value_size=48 off=44 size=8", .result_unpriv = REJECT, .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid map access into an array with a invalid max check", @@ -3129,6 +3171,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.", .result_unpriv = REJECT, .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "multiple registers share map_lookup_elem result", @@ -3252,6 +3295,7 @@ static struct bpf_test tests[] = { .result = REJECT, .errstr_unpriv = "R0 pointer arithmetic prohibited", .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "constant register |= constant should keep constant type", @@ -3981,7 +4025,208 @@ static struct bpf_test tests[] = { .result_unpriv = REJECT, }, { - "map element value (adjusted) is preserved across register spilling", + "map element value or null is marked on register spilling", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -152), + BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_1, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_3, 0, 42), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 leaks addr", + .result = ACCEPT, + .result_unpriv = REJECT, + }, + { + "map element value store of cleared call register", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1), + BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, 0), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R1 !read_ok", + .errstr = "R1 !read_ok", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value with unaligned store", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 17), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 3), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 42), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 2, 43), + BPF_ST_MEM(BPF_DW, BPF_REG_0, -2, 44), + BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), + BPF_ST_MEM(BPF_DW, BPF_REG_8, 0, 32), + BPF_ST_MEM(BPF_DW, BPF_REG_8, 2, 33), + BPF_ST_MEM(BPF_DW, BPF_REG_8, -2, 34), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_8, 5), + BPF_ST_MEM(BPF_DW, BPF_REG_8, 0, 22), + BPF_ST_MEM(BPF_DW, BPF_REG_8, 4, 23), + BPF_ST_MEM(BPF_DW, BPF_REG_8, -7, 24), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_8), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, 3), + BPF_ST_MEM(BPF_DW, BPF_REG_7, 0, 22), + BPF_ST_MEM(BPF_DW, BPF_REG_7, 4, 23), + BPF_ST_MEM(BPF_DW, BPF_REG_7, -4, 24), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .result = ACCEPT, + .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, + }, + { + "map element value with unaligned load", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11), + BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JGE, BPF_REG_1, MAX_ENTRIES, 9), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 3), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 2), + BPF_MOV64_REG(BPF_REG_8, BPF_REG_0), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_8, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_8, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 5), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 4), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .result = ACCEPT, + .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, + }, + { + "map element value illegal alu op, 1", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 8), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 22), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .errstr = "invalid mem access 'inv'", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value illegal alu op, 2", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_ALU32_IMM(BPF_ADD, BPF_REG_0, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 22), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .errstr = "invalid mem access 'inv'", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value illegal alu op, 3", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_ALU64_IMM(BPF_DIV, BPF_REG_0, 42), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 22), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .errstr = "invalid mem access 'inv'", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value illegal alu op, 4", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_ENDIAN(BPF_FROM_BE, BPF_REG_0, 64), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 22), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .errstr = "invalid mem access 'inv'", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value illegal alu op, 5", + .insns = { + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7), + BPF_MOV64_IMM(BPF_REG_3, 4096), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0), + BPF_STX_XADD(BPF_DW, BPF_REG_2, BPF_REG_3, 0), + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 22), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 invalid mem access 'inv'", + .errstr = "R0 invalid mem access 'inv'", + .result = REJECT, + .result_unpriv = REJECT, + }, + { + "map element value is preserved across register spilling", .insns = { BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), @@ -4003,6 +4248,7 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R0 pointer arithmetic prohibited", .result = ACCEPT, .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "helper access to variable memory: stack, bitwise AND + JMP, correct bounds", @@ -4441,6 +4687,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.", .result = REJECT, .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, { "invalid range check", @@ -4472,6 +4719,7 @@ static struct bpf_test tests[] = { .errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.", .result = REJECT, .result_unpriv = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, } }; @@ -4550,11 +4798,11 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog, static void do_test_single(struct bpf_test *test, bool unpriv, int *passes, int *errors) { + int fd_prog, expected_ret, reject_from_alignment; struct bpf_insn *prog = test->insns; int prog_len = probe_filter_length(prog); int prog_type = test->prog_type; int fd_f1 = -1, fd_f2 = -1, fd_f3 = -1; - int fd_prog, expected_ret; const char *expected_err; do_test_fixup(test, prog, &fd_f1, &fd_f2, &fd_f3); @@ -4567,8 +4815,19 @@ static void do_test_single(struct bpf_test *test, bool unpriv, test->result_unpriv : test->result; expected_err = unpriv && test->errstr_unpriv ? test->errstr_unpriv : test->errstr; + + reject_from_alignment = fd_prog < 0 && + (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS) && + strstr(bpf_vlog, "Unknown alignment."); +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + if (reject_from_alignment) { + printf("FAIL\nFailed due to alignment despite having efficient unaligned access: '%s'!\n", + strerror(errno)); + goto fail_log; + } +#endif if (expected_ret == ACCEPT) { - if (fd_prog < 0) { + if (fd_prog < 0 && !reject_from_alignment) { printf("FAIL\nFailed to load prog '%s'!\n", strerror(errno)); goto fail_log; @@ -4578,14 +4837,15 @@ static void do_test_single(struct bpf_test *test, bool unpriv, printf("FAIL\nUnexpected success to load!\n"); goto fail_log; } - if (!strstr(bpf_vlog, expected_err)) { + if (!strstr(bpf_vlog, expected_err) && !reject_from_alignment) { printf("FAIL\nUnexpected error message!\n"); goto fail_log; } } (*passes)++; - printf("OK\n"); + printf("OK%s\n", reject_from_alignment ? + " (NOTE: reject due to unknown alignment)" : ""); close_fds: close(fd_prog); close(fd_f1);