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-rw-r--r--include/linux/bpf.h4
-rw-r--r--include/uapi/linux/bpf.h10
-rw-r--r--kernel/bpf/inode.c16
-rw-r--r--kernel/bpf/syscall.c25
-rw-r--r--tools/include/uapi/linux/bpf.h10
5 files changed, 50 insertions, 15 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 36e4b2d8cca2..f58895830ada 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2077,8 +2077,8 @@ struct file *bpf_link_new_file(struct bpf_link *link, int *reserved_fd);
struct bpf_link *bpf_link_get_from_fd(u32 ufd);
struct bpf_link *bpf_link_get_curr_or_next(u32 *id);
-int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
-int bpf_obj_get_user(const char __user *pathname, int flags);
+int bpf_obj_pin_user(u32 ufd, int path_fd, const char __user *pathname);
+int bpf_obj_get_user(int path_fd, const char __user *pathname, int flags);
#define BPF_ITER_FUNC_PREFIX "bpf_iter_"
#define DEFINE_BPF_ITER_FUNC(target, args...) \
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 1bb11a6ee667..9273c654743c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1272,6 +1272,9 @@ enum {
/* Create a map that will be registered/unregesitered by the backed bpf_link */
BPF_F_LINK = (1U << 13),
+
+/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
+ BPF_F_PATH_FD = (1U << 14),
};
/* Flags for BPF_PROG_QUERY. */
@@ -1420,6 +1423,13 @@ union bpf_attr {
__aligned_u64 pathname;
__u32 bpf_fd;
__u32 file_flags;
+ /* Same as dirfd in openat() syscall; see openat(2)
+ * manpage for details of path FD and pathname semantics;
+ * path_fd should accompanied by BPF_F_PATH_FD flag set in
+ * file_flags field, otherwise it should be set to zero;
+ * if BPF_F_PATH_FD flag is not set, AT_FDCWD is assumed.
+ */
+ __s32 path_fd;
};
struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 329f27d5cacf..4174f76133df 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -435,7 +435,7 @@ static int bpf_iter_link_pin_kernel(struct dentry *parent,
return ret;
}
-static int bpf_obj_do_pin(const char __user *pathname, void *raw,
+static int bpf_obj_do_pin(int path_fd, const char __user *pathname, void *raw,
enum bpf_type type)
{
struct dentry *dentry;
@@ -444,7 +444,7 @@ static int bpf_obj_do_pin(const char __user *pathname, void *raw,
umode_t mode;
int ret;
- dentry = user_path_create(AT_FDCWD, pathname, &path, 0);
+ dentry = user_path_create(path_fd, pathname, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
@@ -477,7 +477,7 @@ out:
return ret;
}
-int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
+int bpf_obj_pin_user(u32 ufd, int path_fd, const char __user *pathname)
{
enum bpf_type type;
void *raw;
@@ -487,14 +487,14 @@ int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
if (IS_ERR(raw))
return PTR_ERR(raw);
- ret = bpf_obj_do_pin(pathname, raw, type);
+ ret = bpf_obj_do_pin(path_fd, pathname, raw, type);
if (ret != 0)
bpf_any_put(raw, type);
return ret;
}
-static void *bpf_obj_do_get(const char __user *pathname,
+static void *bpf_obj_do_get(int path_fd, const char __user *pathname,
enum bpf_type *type, int flags)
{
struct inode *inode;
@@ -502,7 +502,7 @@ static void *bpf_obj_do_get(const char __user *pathname,
void *raw;
int ret;
- ret = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW, &path);
+ ret = user_path_at(path_fd, pathname, LOOKUP_FOLLOW, &path);
if (ret)
return ERR_PTR(ret);
@@ -526,7 +526,7 @@ out:
return ERR_PTR(ret);
}
-int bpf_obj_get_user(const char __user *pathname, int flags)
+int bpf_obj_get_user(int path_fd, const char __user *pathname, int flags)
{
enum bpf_type type = BPF_TYPE_UNSPEC;
int f_flags;
@@ -537,7 +537,7 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
if (f_flags < 0)
return f_flags;
- raw = bpf_obj_do_get(pathname, &type, f_flags);
+ raw = bpf_obj_do_get(path_fd, pathname, &type, f_flags);
if (IS_ERR(raw))
return PTR_ERR(raw);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b2621089904b..c7f6807215e6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2697,23 +2697,38 @@ free_prog:
return err;
}
-#define BPF_OBJ_LAST_FIELD file_flags
+#define BPF_OBJ_LAST_FIELD path_fd
static int bpf_obj_pin(const union bpf_attr *attr)
{
- if (CHECK_ATTR(BPF_OBJ) || attr->file_flags != 0)
+ int path_fd;
+
+ if (CHECK_ATTR(BPF_OBJ) || attr->file_flags & ~BPF_F_PATH_FD)
+ return -EINVAL;
+
+ /* path_fd has to be accompanied by BPF_F_PATH_FD flag */
+ if (!(attr->file_flags & BPF_F_PATH_FD) && attr->path_fd)
return -EINVAL;
- return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname));
+ path_fd = attr->file_flags & BPF_F_PATH_FD ? attr->path_fd : AT_FDCWD;
+ return bpf_obj_pin_user(attr->bpf_fd, path_fd,
+ u64_to_user_ptr(attr->pathname));
}
static int bpf_obj_get(const union bpf_attr *attr)
{
+ int path_fd;
+
if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0 ||
- attr->file_flags & ~BPF_OBJ_FLAG_MASK)
+ attr->file_flags & ~(BPF_OBJ_FLAG_MASK | BPF_F_PATH_FD))
+ return -EINVAL;
+
+ /* path_fd has to be accompanied by BPF_F_PATH_FD flag */
+ if (!(attr->file_flags & BPF_F_PATH_FD) && attr->path_fd)
return -EINVAL;
- return bpf_obj_get_user(u64_to_user_ptr(attr->pathname),
+ path_fd = attr->file_flags & BPF_F_PATH_FD ? attr->path_fd : AT_FDCWD;
+ return bpf_obj_get_user(path_fd, u64_to_user_ptr(attr->pathname),
attr->file_flags);
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 1bb11a6ee667..9273c654743c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1272,6 +1272,9 @@ enum {
/* Create a map that will be registered/unregesitered by the backed bpf_link */
BPF_F_LINK = (1U << 13),
+
+/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
+ BPF_F_PATH_FD = (1U << 14),
};
/* Flags for BPF_PROG_QUERY. */
@@ -1420,6 +1423,13 @@ union bpf_attr {
__aligned_u64 pathname;
__u32 bpf_fd;
__u32 file_flags;
+ /* Same as dirfd in openat() syscall; see openat(2)
+ * manpage for details of path FD and pathname semantics;
+ * path_fd should accompanied by BPF_F_PATH_FD flag set in
+ * file_flags field, otherwise it should be set to zero;
+ * if BPF_F_PATH_FD flag is not set, AT_FDCWD is assumed.
+ */
+ __s32 path_fd;
};
struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
generated by cgit (git 2.34.1) at 2024-06-21 15:49:43 +0000