bpf: improve handling of various sizes of BPF_MAP_CREATE attributes

* bpf.c (BEGIN_BPF_CMD_DECODER(BPF_MAP_CREATE)): Skip printing
the rest of the structure if len is less than the offset of the end
of max_entries, map_flags, or inner_map_fd field.
* tests/bpf.c (BPF_MAP_CREATE_checks): Add two more checks.

diff --git a/bpf.c b/bpf.c
index 8d69424061b168b27cdb4bc9878482d2d5ff45ab..60b55d1639db09f17dfc1afec10c15daf247b48f 100644 (file)
--- a/bpf.c
+++ b/bpf.c
@@ -133,8 +133,23 @@ BEGIN_BPF_CMD_DECODER(BPF_MAP_CREATE)
        PRINT_FIELD_U(", ", attr, key_size);
        PRINT_FIELD_U(", ", attr, value_size);
        PRINT_FIELD_U(", ", attr, max_entries);
+
+       /* map_flags field was added in Linux commit v4.6-rc1~91^2~108^2~6. */
+       if (len <= offsetof(struct BPF_MAP_CREATE_struct, map_flags))
+               break;
        PRINT_FIELD_FLAGS(", ", attr, map_flags, bpf_map_flags, "BPF_F_???");
+
+       /*
+        * inner_map_fd field was added in Linux commit
+        * v4.12-rc1~64^3~373^2~2.
+        */
+       if (len <= offsetof(struct BPF_MAP_CREATE_struct, inner_map_fd))
+               break;
        PRINT_FIELD_FD(", ", attr, inner_map_fd, tcp);
+
+       /* numa_node field was added in Linux commit v4.14-rc1~130^2~196^2~1. */
+       if (len <= offsetof(struct BPF_MAP_CREATE_struct, numa_node))
+               break;
        if (attr.map_flags & BPF_F_NUMA_NODE) {
                /*
                 * Kernel uses the value of -1 as a designation for "no NUMA

diff --git a/tests/bpf.c b/tests/bpf.c
index 59044512c972e3e93000400f6b0912770a80efe0..7dd4ba4a1136b5fea8c57e2d73eda3fbda175b92 100644 (file)
--- a/tests/bpf.c
+++ b/tests/bpf.c
@@ -238,7 +238,7 @@ static const struct bpf_attr_check BPF_MAP_CREATE_checks[] = {
                .data = { .BPF_MAP_CREATE_data = { .map_type = 2 } },
                .size = offsetofend(struct BPF_MAP_CREATE_struct, map_type),
                .str = "map_type=BPF_MAP_TYPE_ARRAY, key_size=0, value_size=0"
-                      ", max_entries=0, map_flags=0, inner_map_fd=0"
+                      ", max_entries=0"
        },
        { /* 1 */
                .data = { .BPF_MAP_CREATE_data = {
@@ -275,6 +275,41 @@ static const struct bpf_attr_check BPF_MAP_CREATE_checks[] = {
                       ", inner_map_fd=-1576685468",
        },
        { /* 3 */
+               .data = { .BPF_MAP_CREATE_data = {
+                       .map_type = 0xdeadf00d,
+                       .key_size = 0xface1e55,
+                       .value_size = 0xbadc0ded,
+                       .max_entries = 0xbeefcafe,
+                       .map_flags = 0xc0dedead,
+                       .inner_map_fd = 2718281828,
+                       .numa_node = -1,
+               } },
+               .size = offsetofend(struct BPF_MAP_CREATE_struct, map_flags),
+               .str = "map_type=0xdeadf00d /* BPF_MAP_TYPE_??? */"
+                      ", key_size=4207812181, value_size=3134983661"
+                      ", max_entries=3203386110"
+                      ", map_flags=BPF_F_NO_PREALLOC|BPF_F_NUMA_NODE"
+                                  "|0xc0dedea8",
+       },
+       { /* 4 */
+               .data = { .BPF_MAP_CREATE_data = {
+                       .map_type = 0xdeadf00d,
+                       .key_size = 0xface1e55,
+                       .value_size = 0xbadc0ded,
+                       .max_entries = 0xbeefcafe,
+                       .map_flags = 0xc0dedead,
+                       .inner_map_fd = 2718281828,
+                       .numa_node = -1,
+               } },
+               .size = offsetofend(struct BPF_MAP_CREATE_struct, inner_map_fd),
+               .str = "map_type=0xdeadf00d /* BPF_MAP_TYPE_??? */"
+                      ", key_size=4207812181, value_size=3134983661"
+                      ", max_entries=3203386110"
+                      ", map_flags=BPF_F_NO_PREALLOC|BPF_F_NUMA_NODE"
+                                  "|0xc0dedea8"
+                      ", inner_map_fd=-1576685468",
+       },
+       { /* 5 */
                .data = { .BPF_MAP_CREATE_data = {
                        .map_type = 0xdeadf00d,
                        .key_size = 0xface1e55,