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authorDavid S. Miller <davem@davemloft.net>2017-05-10 11:38:07 -0700
committerDavid S. Miller <davem@davemloft.net>2017-05-11 14:19:00 -0400
commite07b98d9bffe410019dfcf62c3428d4a96c56a2c (patch)
tree52a3aede39b1bac6a409586bcdd272d9aa958868 /tools
parentc5fc9692d101d1318b0f53f9f691cd88ac029317 (diff)
bpf: Add strict alignment flag for BPF_PROG_LOAD.
Add a new field, "prog_flags", and an initial flag value BPF_F_STRICT_ALIGNMENT. When set, the verifier will enforce strict pointer alignment regardless of the setting of CONFIG_EFFICIENT_UNALIGNED_ACCESS. The verifier, in this mode, will also use a fixed value of "2" in place of NET_IP_ALIGN. This facilitates test cases that will exercise and validate this part of the verifier even when run on architectures where alignment doesn't matter. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/build/feature/test-bpf.c1
-rw-r--r--tools/include/uapi/linux/bpf.h11
2 files changed, 10 insertions, 2 deletions
diff --git a/tools/build/feature/test-bpf.c b/tools/build/feature/test-bpf.c
index ebc6dceddb58..7598361ef1f1 100644
--- a/tools/build/feature/test-bpf.c
+++ b/tools/build/feature/test-bpf.c
@@ -29,6 +29,7 @@ int main(void)
attr.log_size = 0;
attr.log_level = 0;
attr.kern_version = 0;
+ attr.prog_flags = 0;
/*
* Test existence of __NR_bpf and BPF_PROG_LOAD.
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e553529929f6..94dfa9def355 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -132,6 +132,13 @@ enum bpf_attach_type {
*/
#define BPF_F_ALLOW_OVERRIDE (1U << 0)
+/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
+ * verifier will perform strict alignment checking as if the kernel
+ * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
+ * and NET_IP_ALIGN defined to 2.
+ */
+#define BPF_F_STRICT_ALIGNMENT (1U << 0)
+
#define BPF_PSEUDO_MAP_FD 1
/* flags for BPF_MAP_UPDATE_ELEM command */
@@ -177,6 +184,7 @@ union bpf_attr {
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied buffer */
__u32 kern_version; /* checked when prog_type=kprobe */
+ __u32 prog_flags;
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -481,8 +489,7 @@ union bpf_attr {
* u32 bpf_get_socket_uid(skb)
* Get the owner uid of the socket stored inside sk_buff.
* @skb: pointer to skb
- * Return: uid of the socket owner on success or 0 if the socket pointer
- * inside sk_buff is NULL
+ * Return: uid of the socket owner on success or overflowuid if failed.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \

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