Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2017-11-23

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Several BPF offloading fixes, from Jakub. Among others:

    - Limit offload to cls_bpf and XDP program types only.
    - Move device validation into the driver and don't make
      any assumptions about the device in the classifier due
      to shared blocks semantics.
    - Don't pass offloaded XDP program into the driver when
      it should be run in native XDP instead. Offloaded ones
      are not JITed for the host in such cases.
    - Don't destroy device offload state when moved to
      another namespace.
    - Revert dumping offload info into user space for now,
      since ifindex alone is not sufficient. This will be
      redone properly for bpf-next tree.

2) Fix test_verifier to avoid using bpf_probe_write_user()
   helper in test cases, since it's dumping a warning into
   kernel log which may confuse users when only running tests.
   Switch to use bpf_trace_printk() instead, from Yonghong.

3) Several fixes for correcting ARG_CONST_SIZE_OR_ZERO semantics
   before it becomes uabi, from Gianluca. More specifically:

    - Add a type ARG_PTR_TO_MEM_OR_NULL that is used only
      by bpf_csum_diff(), where the argument is either a
      valid pointer or NULL. The subsequent ARG_CONST_SIZE_OR_ZERO
      then enforces a valid pointer in case of non-0 size
      or a valid pointer or NULL in case of size 0. Given
      that, the semantics for ARG_PTR_TO_MEM in combination
      with ARG_CONST_SIZE_OR_ZERO are now such that in case
      of size 0, the pointer must always be valid and cannot
      be NULL. This fix in semantics allows for bpf_probe_read()
      to drop the recently added size == 0 check in the helper
      that would become part of uabi otherwise once released.
      At the same time we can then fix bpf_probe_read_str() and
      bpf_perf_event_output() to use ARG_CONST_SIZE_OR_ZERO
      instead of ARG_CONST_SIZE in order to fix recently
      reported issues by Arnaldo et al, where LLVM optimizes
      two boundary checks into a single one for unknown
      variables where the verifier looses track of the variable
      bounds and thus rejects valid programs otherwise.

4) A fix for the verifier for the case when it detects
   comparison of two constants where the branch is guaranteed
   to not be taken at runtime. Verifier will rightfully prune
   the exploration of such paths, but we still pass the program
   to JITs, where they would complain about using reserved
   fields, etc. Track such dead instructions and sanitize
   them with mov r0,r0. Rejection is not possible since LLVM
   may generate them for valid C code and doesn't do as much
   data flow analysis as verifier. For bpf-next we might
   implement removal of such dead code and adjust branches
   instead. Fix from Alexei.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 123 insertions, 68 deletions

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index f45c44ef9bec..ad619b96c276 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -41,7 +41,6 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
-#include <net/if.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 
@@ -230,21 +229,6 @@ static void print_prog_json(struct bpf_prog_info *info, int fd)
                      info->tag[0], info->tag[1], info->tag[2], info->tag[3],
                      info->tag[4], info->tag[5], info->tag[6], info->tag[7]);
 
-        if (info->status & BPF_PROG_STATUS_DEV_BOUND) {
-                jsonw_name(json_wtr, "dev");
-                if (info->ifindex) {
-                        char name[IF_NAMESIZE];
-
-                        if (!if_indextoname(info->ifindex, name))
-                                jsonw_printf(json_wtr, "\"ifindex:%d\"",
-                                             info->ifindex);
-                        else
-                                jsonw_printf(json_wtr, "\"%s\"", name);
-                } else {
-                        jsonw_printf(json_wtr, "\"unknown\"");
-                }
-        }
-
         if (info->load_time) {
                 char buf[32];
 
@@ -302,21 +286,6 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
 
         printf("tag ");
         fprint_hex(stdout, info->tag, BPF_TAG_SIZE, "");
-        printf(" ");
-
-        if (info->status & BPF_PROG_STATUS_DEV_BOUND) {
-                printf("dev ");
-                if (info->ifindex) {
-                        char name[IF_NAMESIZE];
-
-                        if (!if_indextoname(info->ifindex, name))
-                                printf("ifindex:%d ", info->ifindex);
-                        else
-                                printf("%s ", name);
-                } else {
-                        printf("unknown ");
-                }
-        }
         printf("\n");
 
         if (info->load_time) {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e880ae6434ee..4c223ab30293 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -262,7 +262,7 @@ union bpf_attr {
                 __u32           kern_version;   /* checked when prog_type=kprobe */
                 __u32           prog_flags;
                 char            prog_name[BPF_OBJ_NAME_LEN];
-                __u32           prog_target_ifindex;    /* ifindex of netdev to prep for */
+                __u32           prog_ifindex;   /* ifindex of netdev to prep for */
         };
 
         struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -897,10 +897,6 @@ enum sk_action {
 
 #define BPF_TAG_SIZE    8
 
-enum bpf_prog_status {
-        BPF_PROG_STATUS_DEV_BOUND       = (1 << 0),
-};
-
 struct bpf_prog_info {
         __u32 type;
         __u32 id;
@@ -914,8 +910,6 @@ struct bpf_prog_info {
         __u32 nr_map_ids;
         __aligned_u64 map_ids;
         char name[BPF_OBJ_NAME_LEN];
-        __u32 ifindex;
-        __u32 status;
 } __attribute__((aligned(8)));
 
 struct bpf_map_info {
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index bf092b83e453..3c64f30cf63c 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -4377,11 +4377,10 @@ static struct bpf_test tests[] = {
                         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, 4),
-                        BPF_MOV64_IMM(BPF_REG_1, 0),
-                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
-                        BPF_MOV64_IMM(BPF_REG_3, 0),
-                        BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                        BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                         BPF_EXIT_INSN(),
                 },
                 .fixup_map2 = { 3 },
@@ -4481,14 +4480,12 @@ static struct bpf_test tests[] = {
                         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, 5),
+                        BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
                         BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                         BPF_ALU64_IMM(BPF_ADD, BPF_REG_1,
                                 offsetof(struct test_val, foo)),
-                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                        BPF_MOV64_IMM(BPF_REG_1, 0),
-                        BPF_MOV64_IMM(BPF_REG_3, 0),
-                        BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                         BPF_EXIT_INSN(),
                 },
                 .fixup_map2 = { 3 },
@@ -4618,18 +4615,16 @@ static struct bpf_test tests[] = {
                         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, 6),
+                        BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
                         BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                         BPF_MOV64_IMM(BPF_REG_3, 0),
                         BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
-                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                        BPF_MOV64_IMM(BPF_REG_1, 0),
-                        BPF_MOV64_IMM(BPF_REG_3, 0),
-                        BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                         BPF_EXIT_INSN(),
                 },
                 .fixup_map2 = { 3 },
-                .errstr = "R2 min value is outside of the array range",
+                .errstr = "R1 min value is outside of the array range",
                 .result = REJECT,
                 .prog_type = BPF_PROG_TYPE_TRACEPOINT,
         },
@@ -4760,20 +4755,18 @@ static struct bpf_test tests[] = {
                         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_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
                         BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
                         BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_0, 0),
                         BPF_JMP_IMM(BPF_JGT, BPF_REG_3,
-                                offsetof(struct test_val, foo), 4),
+                                offsetof(struct test_val, foo), 3),
                         BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
-                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
-                        BPF_MOV64_IMM(BPF_REG_1, 0),
-                        BPF_MOV64_IMM(BPF_REG_3, 0),
-                        BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_trace_printk),
                         BPF_EXIT_INSN(),
                 },
                 .fixup_map2 = { 3 },
-                .errstr = "R2 min value is outside of the array range",
+                .errstr = "R1 min value is outside of the array range",
                 .result = REJECT,
                 .prog_type = BPF_PROG_TYPE_TRACEPOINT,
         },
@@ -5638,7 +5631,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_TRACEPOINT,
         },
         {
-                "helper access to variable memory: size = 0 allowed on NULL",
+                "helper access to variable memory: size = 0 allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_MOV64_IMM(BPF_REG_1, 0),
                         BPF_MOV64_IMM(BPF_REG_2, 0),
@@ -5652,7 +5645,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size > 0 not allowed on NULL",
+                "helper access to variable memory: size > 0 not allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_MOV64_IMM(BPF_REG_1, 0),
                         BPF_MOV64_IMM(BPF_REG_2, 0),
@@ -5670,7 +5663,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size = 0 allowed on != NULL stack pointer",
+                "helper access to variable memory: size = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
                         BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
@@ -5687,7 +5680,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size = 0 allowed on != NULL map pointer",
+                "helper access to variable memory: size = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
                         BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5709,7 +5702,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer",
+                "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
                         BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5734,7 +5727,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size possible = 0 allowed on != NULL map pointer",
+                "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
                         BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
@@ -5757,7 +5750,7 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
-                "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer",
+                "helper access to variable memory: size possible = 0 allowed on != NULL packet pointer (ARG_PTR_TO_MEM_OR_NULL)",
                 .insns = {
                         BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
                                     offsetof(struct __sk_buff, data)),
@@ -5779,6 +5772,105 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
         },
         {
+                "helper access to variable memory: size = 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_MOV64_IMM(BPF_REG_1, 0),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .errstr = "R1 type=inv expected=fp",
+                .result = REJECT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
+                "helper access to variable memory: size > 0 not allowed on NULL (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_MOV64_IMM(BPF_REG_1, 0),
+                        BPF_MOV64_IMM(BPF_REG_2, 1),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .errstr = "R1 type=inv expected=fp",
+                .result = REJECT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
+                "helper access to variable memory: size = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
+                "helper access to variable memory: size = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                        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, 4),
+                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                        BPF_MOV64_IMM(BPF_REG_2, 0),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .fixup_map1 = { 3 },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
+                "helper access to variable memory: size possible = 0 allowed on != NULL stack pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                        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, 6),
+                        BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+                        BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 4),
+                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .fixup_map1 = { 3 },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
+                "helper access to variable memory: size possible = 0 allowed on != NULL map pointer (!ARG_PTR_TO_MEM_OR_NULL)",
+                .insns = {
+                        BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+                        BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                        BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                        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, 5),
+                        BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+                        BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+                        BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 8, 2),
+                        BPF_MOV64_IMM(BPF_REG_3, 0),
+                        BPF_EMIT_CALL(BPF_FUNC_probe_read),
+                        BPF_EXIT_INSN(),
+                },
+                .fixup_map1 = { 3 },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+        },
+        {
                 "helper access to variable memory: 8 bytes leak",
                 .insns = {
                         BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),