From 668be05fcab6ebd5077d38114621d84cca6da56a Mon Sep 17 00:00:00 2001
From: Luis Gerhorst <privat@luisgerhorst.de>
Date: Wed, 7 Jul 2021 14:43:50 +0200
Subject: [PATCH] bpf_task_iterdents64: Pass name_user to BPF callback
---
include/uapi/linux/bpf.h | 2 +-
kernel/bpf/task.c | 19 +++++++++++++++++--
tools/include/uapi/linux/bpf.h | 2 +-
3 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 340cbbd160232..cbb0defbd8418 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3845,7 +3845,7 @@ union bpf_attr {
* Return
* TODO.
*
- * int bpf_task_iterdents64(int dir_fd, int prog_fd)
+ * int bpf_task_iterdents64(u32 dir_fd, u32 prog_fd, void *name_user, u32 name_user_size)
* Description
* TODO.
* Return
diff --git a/kernel/bpf/task.c b/kernel/bpf/task.c
index 222f4efb11d5c..06313581b32cd 100644
--- a/kernel/bpf/task.c
+++ b/kernel/bpf/task.c
@@ -123,6 +123,8 @@ struct iterdents_callback64 {
struct bpf_prog *prog;
int dfd;
int error;
+ void __user *name_user;
+ size_t name_user_size;
};
static int iterdents64_actor(struct dir_context *ctx, const char *name, int namelen,
@@ -130,6 +132,8 @@ static int iterdents64_actor(struct dir_context *ctx, const char *name, int name
{
struct iterdents_callback64 *buf =
container_of(ctx, struct iterdents_callback64, ctx);
+ void __user *name_user = buf->name_user;
+ size_t name_user_size = buf->name_user_size;
/* TODO: Is the following required? */
/* buf->error = verify_dirent_name(name, namlen); */
@@ -137,9 +141,16 @@ static int iterdents64_actor(struct dir_context *ctx, const char *name, int name
/* goto ret; */
/* } */
+ if (name_user && namelen + 1 <= name_user_size) {
+ if (copy_to_user(name_user, name, namelen + 1)) {
+ buf->error = -EFAULT;
+ goto ret;
+ }
+ }
+
struct bpf_dirent64 d = {
.name = name,
- .name_end = name + namelen + 1, /* null byte */
+ .name_end = (void *) name + namelen + 1, /* null byte */
.namelen = namelen,
.offset = offset,
.ino = ino,
@@ -155,7 +166,7 @@ static int iterdents64_actor(struct dir_context *ctx, const char *name, int name
return buf->error;
}
-BPF_CALL_2(bpf_task_iterdents64, unsigned int, dfd, unsigned int, prog_fd)
+BPF_CALL_4(bpf_task_iterdents64, u32, dfd, u32, prog_fd, void *, name_user, u32, name_user_size)
{
int ret = 0;
int error;
@@ -163,6 +174,8 @@ BPF_CALL_2(bpf_task_iterdents64, unsigned int, dfd, unsigned int, prog_fd)
struct iterdents_callback64 buf = {
.ctx.actor = iterdents64_actor,
.dfd = dfd,
+ .name_user = name_user,
+ .name_user_size = name_user_size,
};
/* TODO: Check priviledge level / capability of current process before
@@ -201,6 +214,8 @@ const struct bpf_func_proto bpf_task_iterdents64_proto = {
.ret_type = RET_INTEGER,
.arg1_type = ARG_ANYTHING,
.arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_ANYTHING,
+ .arg4_type = ARG_ANYTHING,
};
long do_open_kernel(int dfd, const char *filename, int flags, umode_t mode);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 079cd34b3858d..09242c14dbc51 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3845,7 +3845,7 @@ union bpf_attr {
* Return
* TODO.
*
- * int bpf_task_iterdents64(int dir_fd, int prog_fd)
+ * int bpf_task_iterdents64(u32 dir_fd, u32 prog_fd, void *name_user, u32 name_user_size)
* Description
* TODO.
* Return
--
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