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bpf: btf: check name validity for various types

PATCH Applied Yonghong Song 2 participants 6 messages Nov 28, 2018 – Nov 29, 2018

Subsystems (5)
Networking Network drivers Kselftest BPF +1 more subsystems
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Yonghong Song

author
#0 lore raw

v2 cover bpf: btf: check name validity for various types

This patch set added name checking for PTR, ARRAY, VOLATILE, TYPEDEF, CONST, RESTRICT, STRUCT, UNION, ENUM and FWD types. Such a strict name checking makes BTF more sound in the kernel and future BTF-to-header-file converesion ([1]) less fragile.

Patch #1 implemented btf_name_valid_identifier() for name checking which will be used in Patch #2.
Patch #2 checked name validity for the above mentioned types. Patch #3 fixed two existing test_btf unit tests exposed by the strict name checking.
Patch #4 added additional test cases.

This patch set is against bpf tree.

Patch #1 has been implemented in bpf-next commit
Commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC
and BTF_KIND_FUNC_PROTO"), so there is no need to apply this patch to bpf-next. In case this patch is applied to bpf-next, there will be a minor conflict like
diff --cc kernel/bpf/btf.c
index a09b2f94ab25,93c233ab2db6..000000000000
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@@ -474,7 -451,7 +474,11 @@@ static bool btf_name_valid_identifier(c

          return !*src;
    }

++<<<<<<< HEAD
+const char *btf_name_by_offset(const struct btf *btf, u32 offset)
++=======
+ static const char *btf_name_by_offset(const struct btf *btf, u32 offset) ++>>>>>>> fa9566b0847d... bpf: btf: implement btf_name_valid_identifier()

    {
          if (!offset)
                  return "(anon)";

Just resolve the conflict by taking the "const char ..." line.

Patches #2, #3 and #4 can be applied to bpf-next without conflict.

[1]: http://vger.kernel.org/lpc-bpf2018.html#session-2

Yonghong Song (4):
bpf: btf: implement btf_name_valid_identifier()
bpf: btf: check name validity for various types
tools/bpf: fix two test_btf unit test cases
tools/bpf: add addition type tests to test_btf

 kernel/bpf/btf.c                       |  82 ++++++
 tools/testing/selftests/bpf/test_btf.c | 375 ++++++++++++++++++++++++-
 2 files changed, 450 insertions(+), 7 deletions(-)
Signature · 1 line
2.17.1
author
#1 lore raw

PATCH v2 1/4 bpf: btf: implement btf_name_valid_identifier()

Function btf_name_valid_identifier() have been implemented in bpf-next commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO"). Backport this function so later patch can use it.

Fixes 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by Yonghong Song <[email protected]>
---
 kernel/bpf/btf.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
kernel/bpf/btf.c +25 -0
index ee4c82667d65..93c233ab2db6 100644
@@ -5,6 +5,7 @@
 #include <uapi/linux/types.h>
 #include <linux/seq_file.h>
 #include <linux/compiler.h>
+#include <linux/ctype.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/anon_inodes.h>

@@ -426,6 +427,30 @@ static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
 		offset < btf->hdr.str_len;
 }
 
+/* Only C-style identifier is permitted. This can be relaxed if
+ * necessary.
+ */
+static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
+{
+	/* offset must be valid */
+	const char *src = &btf->strings[offset];
+	const char *src_limit;
+
+	if (!isalpha(*src) && *src != '_')
+		return false;
+
+	/* set a limit on identifier length */
+	src_limit = src + KSYM_NAME_LEN;
+	src++;
+	while (*src && src < src_limit) {
+		if (!isalnum(*src) && *src != '_')
+			return false;
+		src++;
+	}
+
+	return !*src;
+}
+
 static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
 {
 	if (!offset)
Signature · 1 line
2.17.1
author
#2 lore raw

PATCH v2 2/4 bpf: btf: check name validity for various types

In reply to Yonghong Song

This patch added name checking for the following types:
. BTF_KIND_PTR, BTF_KIND_ARRAY, BTF_KIND_VOLATILE,
BTF_KIND_CONST, BTF_KIND_RESTRICT:
the name must be null
. BTF_KIND_STRUCT, BTF_KIND_UNION: the struct/member name
is either null or a valid identifier
. BTF_KIND_ENUM: the enum type name is either null or a valid
identifier; the enumerator name must be a valid identifier.
. BTF_KIND_FWD: the name must be a valid identifier
. BTF_KIND_TYPEDEF: the name must be a valid identifier

For those places a valid name is required, the name must be a valid C identifier. This can be relaxed later if we found use cases for a different (non-C) frontend.

Fixes 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Acked-by Martin KaFai Lau <[email protected]>
Signed-off-by Yonghong Song <[email protected]>
---
 kernel/bpf/btf.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
kernel/bpf/btf.c +57 -0
index 93c233ab2db6..4da543d6bea2 100644
@@ -1168,6 +1168,22 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	/* typedef type must have a valid name, and other ref types,
+	 * volatile, const, restrict, should have a null name.
+	 */
+	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
+		if (!t->name_off ||
+		    !btf_name_valid_identifier(env->btf, t->name_off)) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+	} else {
+		if (t->name_off) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	return 0;

@@ -1325,6 +1341,13 @@ static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	/* fwd type must have a valid name */
+	if (!t->name_off ||
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	return 0;

@@ -1381,6 +1404,12 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	/* array type should not have a name */
+	if (t->name_off) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
 	if (btf_type_vlen(t)) {
 		btf_verifier_log_type(env, t, "vlen != 0");
 		return -EINVAL;

@@ -1557,6 +1586,13 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	/* struct type either no name or a valid one */
+	if (t->name_off &&
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	last_offset = 0;

@@ -1568,6 +1604,12 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
 			return -EINVAL;
 		}
 
+		/* struct member either no name or a valid one */
+		if (member->name_off &&
+		    !btf_name_valid_identifier(btf, member->name_off)) {
+			btf_verifier_log_member(env, t, member, "Invalid name");
+			return -EINVAL;
+		}
 		/* A member cannot be in type void */
 		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
 			btf_verifier_log_member(env, t, member,

@@ -1755,6 +1797,13 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
 		return -EINVAL;
 	}
 
+	/* enum type either no name or a valid one */
+	if (t->name_off &&
+	    !btf_name_valid_identifier(env->btf, t->name_off)) {
+		btf_verifier_log_type(env, t, "Invalid name");
+		return -EINVAL;
+	}
+
 	btf_verifier_log_type(env, t, NULL);
 
 	for (i = 0; i < nr_enums; i++) {

@@ -1764,6 +1813,14 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
 			return -EINVAL;
 		}
 
+		/* enum member must have a valid name */
+		if (!enums[i].name_off ||
+		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
+			btf_verifier_log_type(env, t, "Invalid name");
+			return -EINVAL;
+		}
+
+
 		btf_verifier_log(env, "\t%s val=%d\n",
 				 btf_name_by_offset(btf, enums[i].name_off),
 				 enums[i].val);
Signature · 1 line
2.17.1
author
#3 lore raw

PATCH v2 3/4 tools/bpf: fix two test_btf unit test cases

In reply to Yonghong Song

From: Martin KaFai Lau <[email protected]>

There are two unit test cases, which should encode TYPEDEF type, but instead encode PTR type. The error is flagged out after enforcing name checking in the previous patch.

Fixes c0fa1b6c3efc ("bpf: btf: Add BTF tests")
Signed-off-by Martin KaFai Lau <[email protected]>
Signed-off-by Yonghong Song <[email protected]>
---
 tools/testing/selftests/bpf/test_btf.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
tools/testing/selftests/bpf/test_btf.c +7 -7
index f42b3396d622..b361bb851829 100644
@@ -432,11 +432,11 @@ static struct btf_raw_test raw_tests[] = {
 		/* const void* */	/* [3] */
 		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),
 		/* typedef const void * const_void_ptr */
-		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 3),
-		/* struct A { */	/* [4] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 3),	/* [4] */
+		/* struct A { */	/* [5] */
 		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), sizeof(void *)),
 		/* const_void_ptr m; */
-		BTF_MEMBER_ENC(NAME_TBD, 3, 0),
+		BTF_MEMBER_ENC(NAME_TBD, 4, 0),
 		/* } */
 		BTF_END_RAW,
 	},

@@ -494,10 +494,10 @@ static struct btf_raw_test raw_tests[] = {
 		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 0),
 		/* const void* */	/* [3] */
 		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2),
-		/* typedef const void * const_void_ptr */	/* [4] */
-		BTF_TYPE_ENC(NAME_TBD, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 3),
-		/* const_void_ptr[4] */	/* [5] */
-		BTF_TYPE_ARRAY_ENC(3, 1, 4),
+		/* typedef const void * const_void_ptr */
+		BTF_TYPEDEF_ENC(NAME_TBD, 3),	/* [4] */
+		/* const_void_ptr[4] */
+		BTF_TYPE_ARRAY_ENC(4, 1, 4),	/* [5] */
 		BTF_END_RAW,
 	},
 	.str_sec = "\0const_void_ptr",
Signature · 1 line
2.17.1
author
#4 lore raw

PATCH v2 4/4 tools/bpf: add addition type tests to test_btf

In reply to Yonghong Song

The following additional unit testcases are added to test_btf:
...
BTF raw test[42] (typedef (invalid name, name_off = 0)): OK BTF raw test[43] (typedef (invalid name, invalid identifier)): OK BTF raw test[44] (ptr type (invalid name, name_off <> 0)): OK BTF raw test[45] (volatile type (invalid name, name_off <> 0)): OK BTF raw test[46] (const type (invalid name, name_off <> 0)): OK BTF raw test[47] (restrict type (invalid name, name_off <> 0)): OK BTF raw test[48] (fwd type (invalid name, name_off = 0)): OK BTF raw test[49] (fwd type (invalid name, invalid identifier)): OK BTF raw test[50] (array type (invalid name, name_off <> 0)): OK BTF raw test[51] (struct type (name_off = 0)): OK
BTF raw test[52] (struct type (invalid name, invalid identifier)): OK BTF raw test[53] (struct member (name_off = 0)): OK
BTF raw test[54] (struct member (invalid name, invalid identifier)): OK BTF raw test[55] (enum type (name_off = 0)): OK
BTF raw test[56] (enum type (invalid name, invalid identifier)): OK BTF raw test[57] (enum member (invalid name, name_off = 0)): OK BTF raw test[58] (enum member (invalid name, invalid identifier)): OK
...

Fixes c0fa1b6c3efc ("bpf: btf: Add BTF tests")
Acked-by Martin KaFai Lau <[email protected]>
Signed-off-by Yonghong Song <[email protected]>
---
 tools/testing/selftests/bpf/test_btf.c | 361 +++++++++++++++++++++++++
 1 file changed, 361 insertions(+)
tools/testing/selftests/bpf/test_btf.c +361 -0
index b361bb851829..38e1cbaaffdb 100644
@@ -1292,6 +1292,367 @@ static struct btf_raw_test raw_tests[] = {
 	.err_str = "type != 0",
 },
 
+{
+	.descr = "typedef (invalid name, name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_TYPEDEF_ENC(0, 1),				/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__int",
+	.str_sec_size = sizeof("\0__int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "typedef_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "typedef (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_TYPEDEF_ENC(NAME_TBD, 1),			/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__!int",
+	.str_sec_size = sizeof("\0__!int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "typedef_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "ptr type (invalid name, name_off <> 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__int",
+	.str_sec_size = sizeof("\0__int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "ptr_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "volatile type (invalid name, name_off <> 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_VOLATILE, 0, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__int",
+	.str_sec_size = sizeof("\0__int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "volatile_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "const type (invalid name, name_off <> 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_CONST, 0, 0), 1),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__int",
+	.str_sec_size = sizeof("\0__int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "const_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "restrict type (invalid name, name_off <> 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 1),	/* [2] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_RESTRICT, 0, 0), 2),	/* [3] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__int",
+	.str_sec_size = sizeof("\0__int"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "restrict_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "fwd type (invalid name, name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FWD, 0, 0), 0),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__skb",
+	.str_sec_size = sizeof("\0__skb"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "fwd_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "fwd type (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_FWD, 0, 0), 0),	/* [2] */
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__!skb",
+	.str_sec_size = sizeof("\0__!skb"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "fwd_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "array type (invalid name, name_off <> 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_ARRAY, 0, 0), 0),	/* [2] */
+		BTF_ARRAY_ENC(1, 1, 4),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0__skb",
+	.str_sec_size = sizeof("\0__skb"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "array_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "struct type (name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0,
+			     BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "struct type (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A!\0B",
+	.str_sec_size = sizeof("\0A!\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "struct member (name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0,
+			     BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A",
+	.str_sec_size = sizeof("\0A"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "struct member (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),	/* [2] */
+		BTF_MEMBER_ENC(NAME_TBD, 1, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B*",
+	.str_sec_size = sizeof("\0A\0B*"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "struct_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "enum type (name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0,
+			     BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
+			     sizeof(int)),				/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A\0B",
+	.str_sec_size = sizeof("\0A\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "enum_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+},
+
+{
+	.descr = "enum type (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(NAME_TBD,
+			     BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
+			     sizeof(int)),				/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A!\0B",
+	.str_sec_size = sizeof("\0A!\0B"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "enum_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "enum member (invalid name, name_off = 0)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0,
+			     BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
+			     sizeof(int)),				/* [2] */
+		BTF_ENUM_ENC(0, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "",
+	.str_sec_size = sizeof(""),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "enum_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
+
+{
+	.descr = "enum member (invalid name, invalid identifier)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),		/* [1] */
+		BTF_TYPE_ENC(0,
+			     BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1),
+			     sizeof(int)),				/* [2] */
+		BTF_ENUM_ENC(NAME_TBD, 0),
+		BTF_END_RAW,
+	},
+	.str_sec = "\0A!",
+	.str_sec_size = sizeof("\0A!"),
+	.map_type = BPF_MAP_TYPE_ARRAY,
+	.map_name = "enum_type_check_btf",
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.key_type_id = 1,
+	.value_type_id = 1,
+	.max_entries = 4,
+	.btf_load_err = true,
+	.err_str = "Invalid name",
+},
 {
 	.descr = "arraymap invalid btf key (a bit field)",
 	.raw_types = {
Signature · 1 line
2.17.1
Applied
#5 lore raw
In reply to Yonghong Song
Quoted 32 lines · Yonghong Song

This patch set added name checking for PTR, ARRAY, VOLATILE, TYPEDEF, CONST, RESTRICT, STRUCT, UNION, ENUM and FWD types. Such a strict name checking makes BTF more sound in the kernel and future BTF-to-header-file converesion ([1]) less fragile.

Patch #1 implemented btf_name_valid_identifier() for name checking which will be used in Patch #2.
Patch #2 checked name validity for the above mentioned types. Patch #3 fixed two existing test_btf unit tests exposed by the strict name checking.
Patch #4 added additional test cases.

This patch set is against bpf tree.

Patch #1 has been implemented in bpf-next commit
Commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC
and BTF_KIND_FUNC_PROTO"), so there is no need to apply this patch to bpf-next. In case this patch is applied to bpf-next, there will be a minor conflict like
diff --cc kernel/bpf/btf.c
index a09b2f94ab25,93c233ab2db6..000000000000
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@@ -474,7 -451,7 +474,11 @@@ static bool btf_name_valid_identifier(c

          return !*src;
    }

++<<<<<<< HEAD
+const char *btf_name_by_offset(const struct btf *btf, u32 offset)
++=======
+ static const char *btf_name_by_offset(const struct btf *btf, u32 offset) ++>>>>>>> fa9566b0847d... bpf: btf: implement btf_name_valid_identifier()

Quoted 8 lines
    {
          if (!offset)
                  return "(anon)";

Just resolve the conflict by taking the "const char ..." line.

Patches #2, #3 and #4 can be applied to bpf-next without conflict.

[1]: http://vger.kernel.org/lpc-bpf2018.html#session-2

Applied to bpf tree. Thanks!