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From: Hangbin Liu <liuhangbin@gmail.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Jiri Benc" <jbenc@redhat.com>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Eelco Chaudron" <echaudro@redhat.com>,
	ast@kernel.org, "Daniel Borkmann" <daniel@iogearbox.net>,
	"Lorenzo Bianconi" <lorenzo.bianconi@redhat.com>,
	"David Ahern" <dsahern@gmail.com>,
	"Andrii Nakryiko B" <andrii.nakryiko@gmail.com>,
	"Hangbin Liu" <liuhangbin@gmail.com>
Subject: [PATCHv9 bpf-next 1/5] bpf: add a new bpf argument type ARG_CONST_MAP_PTR_OR_NULL
Date: Wed, 26 Aug 2020 21:19:58 +0800
Message-ID: <20200826132002.2808380-2-liuhangbin@gmail.com> (raw)
In-Reply-To: <20200826132002.2808380-1-liuhangbin@gmail.com>

Add a new bpf argument type ARG_CONST_MAP_PTR_OR_NULL which could be
used when we want to allow NULL pointer for map parameter. The bpf helper
need to take care and check if the map is NULL when use this type.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---

v9: merge the patch from [1] in to this series.
v1-v8: no this patch

[1] https://lore.kernel.org/bpf/20200715070001.2048207-1-liuhangbin@gmail.com/
---
 include/linux/bpf.h   |  2 ++
 kernel/bpf/verifier.c | 23 ++++++++++++++++-------
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a6131d95e31e..cb40a1281ea2 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -276,6 +276,7 @@ enum bpf_arg_type {
 	ARG_PTR_TO_ALLOC_MEM,	/* pointer to dynamically allocated memory */
 	ARG_PTR_TO_ALLOC_MEM_OR_NULL,	/* pointer to dynamically allocated memory or NULL */
 	ARG_CONST_ALLOC_SIZE_OR_ZERO,	/* number of allocated bytes requested */
+	ARG_CONST_MAP_PTR_OR_NULL,	/* const argument used as pointer to bpf_map or NULL */
 };
 
 /* type of values returned from helper functions */
@@ -369,6 +370,7 @@ enum bpf_reg_type {
 	PTR_TO_RDONLY_BUF_OR_NULL, /* reg points to a readonly buffer or NULL */
 	PTR_TO_RDWR_BUF,	 /* reg points to a read/write buffer */
 	PTR_TO_RDWR_BUF_OR_NULL, /* reg points to a read/write buffer or NULL */
+	CONST_PTR_TO_MAP_OR_NULL, /* reg points to struct bpf_map or NULL */
 };
 
 /* The information passed from prog-specific *_is_valid_access
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 7e5908b83ec7..53a84335a8fd 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -411,7 +411,8 @@ static bool reg_type_may_be_null(enum bpf_reg_type type)
 	       type == PTR_TO_BTF_ID_OR_NULL ||
 	       type == PTR_TO_MEM_OR_NULL ||
 	       type == PTR_TO_RDONLY_BUF_OR_NULL ||
-	       type == PTR_TO_RDWR_BUF_OR_NULL;
+	       type == PTR_TO_RDWR_BUF_OR_NULL ||
+	       type == CONST_PTR_TO_MAP_OR_NULL;
 }
 
 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
@@ -427,7 +428,8 @@ static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
 		type == PTR_TO_TCP_SOCK ||
 		type == PTR_TO_TCP_SOCK_OR_NULL ||
 		type == PTR_TO_MEM ||
-		type == PTR_TO_MEM_OR_NULL;
+		type == PTR_TO_MEM_OR_NULL ||
+		type == CONST_PTR_TO_MAP_OR_NULL;
 }
 
 static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
@@ -509,6 +511,7 @@ static const char * const reg_type_str[] = {
 	[PTR_TO_RDONLY_BUF_OR_NULL] = "rdonly_buf_or_null",
 	[PTR_TO_RDWR_BUF]	= "rdwr_buf",
 	[PTR_TO_RDWR_BUF_OR_NULL] = "rdwr_buf_or_null",
+	[CONST_PTR_TO_MAP_OR_NULL] = "map_ptr_or_null",
 };
 
 static char slot_type_char[] = {
@@ -3957,9 +3960,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		expected_type = SCALAR_VALUE;
 		if (type != expected_type)
 			goto err_type;
-	} else if (arg_type == ARG_CONST_MAP_PTR) {
+	} else if (arg_type == ARG_CONST_MAP_PTR ||
+		   arg_type == ARG_CONST_MAP_PTR_OR_NULL) {
 		expected_type = CONST_PTR_TO_MAP;
-		if (type != expected_type)
+		if (register_is_null(reg) &&
+		    arg_type == ARG_CONST_MAP_PTR_OR_NULL)
+			/* final test in check_stack_boundary() */;
+		else if (type != expected_type)
 			goto err_type;
 	} else if (arg_type == ARG_PTR_TO_CTX ||
 		   arg_type == ARG_PTR_TO_CTX_OR_NULL) {
@@ -4076,9 +4083,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
 		return -EFAULT;
 	}
 
-	if (arg_type == ARG_CONST_MAP_PTR) {
-		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
-		meta->map_ptr = reg->map_ptr;
+	if (arg_type == ARG_CONST_MAP_PTR ||
+	    arg_type == ARG_CONST_MAP_PTR_OR_NULL) {
+		meta->map_ptr = register_is_null(reg) ? NULL : reg->map_ptr;
 	} else if (arg_type == ARG_PTR_TO_MAP_KEY) {
 		/* bpf_map_xxx(..., map_ptr, ..., key) call:
 		 * check that [key, key + map->key_size) are within
@@ -6977,6 +6984,8 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
 			reg->type = PTR_TO_RDONLY_BUF;
 		} else if (reg->type == PTR_TO_RDWR_BUF_OR_NULL) {
 			reg->type = PTR_TO_RDWR_BUF;
+		} else if (reg->type == CONST_PTR_TO_MAP_OR_NULL) {
+			reg->type = CONST_PTR_TO_MAP;
 		}
 		if (is_null) {
 			/* We don't need id and ref_obj_id from this point
-- 
2.25.4


  reply index

Thread overview: 127+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15  8:54 [RFC PATCH bpf-next 0/2] xdp: add dev map multicast support Hangbin Liu
2020-04-15  8:54 ` [RFC PATCH bpf-next 1/2] " Hangbin Liu
2020-04-20  9:52   ` Hangbin Liu
2020-04-15  8:54 ` [RFC PATCH bpf-next 2/2] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-04-24  8:56 ` [RFC PATCHv2 bpf-next 0/2] xdp: add dev map multicast support Hangbin Liu
2020-04-24  8:56   ` [RFC PATCHv2 bpf-next 1/2] xdp: add a new helper for " Hangbin Liu
2020-04-24 14:19     ` Lorenzo Bianconi
2020-04-28 11:09       ` Eelco Chaudron
2020-05-06  9:35       ` Hangbin Liu
2020-04-24 14:34     ` Toke Høiland-Jørgensen
2020-05-06  9:14       ` Hangbin Liu
2020-05-06 10:00         ` Toke Høiland-Jørgensen
2020-05-08  8:53           ` Hangbin Liu
2020-05-08 14:58             ` Toke Høiland-Jørgensen
2020-05-18  8:45       ` Hangbin Liu
2020-05-19 10:15         ` Jesper Dangaard Brouer
2020-05-20  1:24           ` Hangbin Liu
2020-04-24  8:56   ` [RFC PATCHv2 bpf-next 2/2] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-04-24 14:21     ` Lorenzo Bianconi
2020-05-23  6:05 ` [PATCHv3 bpf-next 0/2] xdp: add dev map multicast support Hangbin Liu
2020-05-23  6:05   ` [PATCHv3 bpf-next 1/2] xdp: add a new helper for " Hangbin Liu
2020-05-26  7:34     ` kbuild test robot
2020-05-23  6:05   ` [PATCHv3 bpf-next 2/2] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-05-26 14:05 ` [PATCHv4 bpf-next 0/2] xdp: add dev map multicast support Hangbin Liu
2020-05-26 14:05   ` [PATCHv4 bpf-next 1/2] xdp: add a new helper for " Hangbin Liu
2020-05-27 10:29     ` Toke Høiland-Jørgensen
2020-06-10 10:18     ` Jesper Dangaard Brouer
2020-06-12  8:54       ` Hangbin Liu
2020-06-16  8:55         ` Jesper Dangaard Brouer
2020-06-16 10:11           ` Hangbin Liu
2020-06-16 14:38             ` Jesper Dangaard Brouer
2020-06-10 10:21     ` Jesper Dangaard Brouer
2020-06-10 10:29       ` Toke Høiland-Jørgensen
2020-06-16  9:04         ` Jesper Dangaard Brouer
2020-05-26 14:05   ` [PATCHv4 bpf-next 2/2] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-05-27 10:21   ` [PATCHv4 bpf-next 0/2] xdp: add dev map multicast support Toke Høiland-Jørgensen
2020-05-27 10:32     ` Eelco Chaudron
2020-05-27 12:38     ` Hangbin Liu
2020-05-27 15:04       ` Toke Høiland-Jørgensen
2020-06-16  9:09         ` Jesper Dangaard Brouer
2020-06-16  9:47           ` Hangbin Liu
2020-06-03  2:40     ` Hangbin Liu
2020-06-03 11:05       ` Toke Høiland-Jørgensen
2020-06-04  4:09         ` Hangbin Liu
2020-06-04  9:44           ` Toke Høiland-Jørgensen
2020-06-04 12:12             ` Hangbin Liu
2020-06-04 12:37               ` Toke Høiland-Jørgensen
2020-06-04 14:41                 ` Hangbin Liu
2020-06-04 16:02                   ` Toke Høiland-Jørgensen
2020-06-05  6:26                     ` Hangbin Liu
2020-06-08 15:32                       ` Toke Høiland-Jørgensen
2020-06-09  3:03                         ` Hangbin Liu
2020-06-09 20:31                           ` Toke Høiland-Jørgensen
2020-06-10  2:35                             ` Hangbin Liu
2020-06-10 10:03                               ` Jesper Dangaard Brouer
2020-07-01  4:19   ` [PATCHv5 bpf-next 0/3] xdp: add a new helper for " Hangbin Liu
2020-07-01  4:19     ` [PATCHv5 bpf-next 1/3] " Hangbin Liu
2020-07-01  5:09       ` Andrii Nakryiko
2020-07-01  6:51         ` Hangbin Liu
2020-07-01 18:33       ` kernel test robot
2020-07-01  4:19     ` [PATCHv5 bpf-next 2/3] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-07-01  4:19     ` [PATCHv5 bpf-next 3/3] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-07-09  1:30     ` [PATCHv6 bpf-next 0/3] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-07-09  1:30       ` [PATCHv6 bpf-next 1/3] " Hangbin Liu
2020-07-09 16:33         ` David Ahern
2020-07-10  6:55           ` Hangbin Liu
2020-07-10 13:46             ` David Ahern
2020-07-11  0:26               ` Hangbin Liu
2020-07-11 16:09                 ` David Ahern
2020-07-09  1:30       ` [PATCHv6 bpf-next 2/3] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-07-09 22:40         ` Daniel Borkmann
2020-07-10  6:41           ` Hangbin Liu
2020-07-10 14:32             ` Daniel Borkmann
2020-07-11  0:21               ` Hangbin Liu
2020-07-09  1:30       ` [PATCHv6 bpf-next 3/3] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-07-09 22:37       ` [PATCHv6 bpf-next 0/3] xdp: add a new helper for dev map multicast support Daniel Borkmann
2020-07-10  7:36         ` Hangbin Liu
2020-07-10 15:02           ` Daniel Borkmann
2020-07-10 16:52             ` David Ahern
2020-07-14  6:32       ` [PATCHv7 " Hangbin Liu
2020-07-14  6:32         ` [PATCHv7 bpf-next 1/3] " Hangbin Liu
2020-07-14 21:52           ` Toke Høiland-Jørgensen
2020-07-15 12:25             ` Hangbin Liu
2020-07-14  6:32         ` [PATCHv7 bpf-next 2/3] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-07-14  6:32         ` [PATCHv7 bpf-next 3/3] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-07-14 12:29         ` [PATCHv7 bpf-next 0/3] xdp: add a new helper for dev map multicast support Toke Høiland-Jørgensen
2020-07-14 17:12           ` David Ahern
2020-07-14 21:53             ` Toke Høiland-Jørgensen
2020-07-15 12:31               ` Hangbin Liu
2020-07-15  3:45             ` Hangbin Liu
2020-07-15 13:08         ` [PATCHv8 " Hangbin Liu
2020-07-15 13:08           ` [PATCHv8 bpf-next 1/3] " Hangbin Liu
2020-07-15 13:08           ` [PATCHv8 bpf-next 2/3] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-07-15 13:08           ` [PATCHv8 bpf-next 3/3] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-08-26 13:19           ` [PATCHv9 bpf-next 0/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-08-26 13:19             ` Hangbin Liu [this message]
2020-08-28 21:56               ` [PATCHv9 bpf-next 1/5] bpf: add a new bpf argument type ARG_CONST_MAP_PTR_OR_NULL Daniel Borkmann
2020-09-03  9:15                 ` Hangbin Liu
2020-08-26 13:19             ` [PATCHv9 bpf-next 2/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-08-28 22:05               ` Daniel Borkmann
2020-08-26 13:20             ` [PATCHv9 bpf-next 3/5] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-08-26 13:20             ` [PATCHv9 bpf-next 4/5] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-08-26 13:20             ` [PATCHv9 bpf-next 5/5] selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL Hangbin Liu
2020-09-03 10:26             ` [PATCHv10 bpf-next 0/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-09-03 10:26               ` [PATCHv10 bpf-next 1/5] bpf: add a new bpf argument type ARG_CONST_MAP_PTR_OR_NULL Hangbin Liu
2020-09-04 14:26                 ` Daniel Borkmann
2020-09-03 10:26               ` [PATCHv10 bpf-next 2/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-09-04 14:22                 ` Daniel Borkmann
2020-09-03 10:26               ` [PATCHv10 bpf-next 3/5] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-09-03 10:27               ` [PATCHv10 bpf-next 4/5] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-09-03 10:27               ` [PATCHv10 bpf-next 5/5] selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL Hangbin Liu
2020-09-07  8:27               ` [PATCHv11 bpf-next 0/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-09-07  8:27                 ` [PATCHv11 bpf-next 1/5] bpf: add a new bpf argument type ARG_CONST_MAP_PTR_OR_NULL Hangbin Liu
2020-09-07  8:27                 ` [PATCHv11 bpf-next 2/5] xdp: add a new helper for dev map multicast support Hangbin Liu
2020-09-09 21:52                   ` Alexei Starovoitov
2020-09-10  2:35                     ` Hangbin Liu
2020-09-10  3:30                       ` David Ahern
2020-09-10  5:35                         ` Alexei Starovoitov
2020-09-10  9:44                           ` Toke Høiland-Jørgensen
2020-09-10 15:39                             ` Alexei Starovoitov
2020-09-10 17:50                             ` Jesper Dangaard Brouer
2020-09-10 18:35                               ` David Ahern
2020-09-11  7:58                                 ` Jesper Dangaard Brouer
2020-09-15 16:12                                   ` David Ahern
2020-09-07  8:27                 ` [PATCHv11 bpf-next 3/5] sample/bpf: add xdp_redirect_map_multicast test Hangbin Liu
2020-09-07  8:27                 ` [PATCHv11 bpf-next 4/5] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2020-09-07  8:27                 ` [PATCHv11 bpf-next 5/5] selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL Hangbin Liu

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