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Commit 040ee692 authored by Al Viro's avatar Al Viro
Browse files

fix "netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'" 



Descriptor table is a shared object; it's not a place where you can
stick temporary references to files, especially when we don't need
an opened file at all.

Cc: stable@vger.kernel.org # v4.14
Fixes: 98589a09 ("netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'")
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9ee332d9

include/linux/bpf.h

+10 −0
Original line number Diff line number Diff line
@@ -419,6 +419,8 @@ static inline int bpf_map_attr_numa_node(const union bpf_attr *attr) 
		attr->numa_node : NUMA_NO_NODE;

}



struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type);



#else /* !CONFIG_BPF_SYSCALL */

static inline struct bpf_prog *bpf_prog_get(u32 ufd)

{
@@ -506,6 +508,12 @@ static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, 
{

	return 0;

}



static inline struct bpf_prog *bpf_prog_get_type_path(const char *name,

				enum bpf_prog_type type)

{

	return ERR_PTR(-EOPNOTSUPP);

}

#endif /* CONFIG_BPF_SYSCALL */



static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
@@ -514,6 +522,8 @@ static inline struct bpf_prog *bpf_prog_get_type(u32 ufd, 
	return bpf_prog_get_type_dev(ufd, type, false);

}



bool bpf_prog_get_ok(struct bpf_prog *, enum bpf_prog_type *, bool);



int bpf_prog_offload_compile(struct bpf_prog *prog);

void bpf_prog_offload_destroy(struct bpf_prog *prog);

kernel/bpf/inode.c

+39 −1
Original line number Diff line number Diff line
@@ -368,7 +368,45 @@ int bpf_obj_get_user(const char __user *pathname, int flags) 
	putname(pname);

	return ret;

}

EXPORT_SYMBOL_GPL(bpf_obj_get_user);



static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)

{

	struct bpf_prog *prog;

	int ret = inode_permission(inode, MAY_READ | MAY_WRITE);

	if (ret)

		return ERR_PTR(ret);



	if (inode->i_op == &bpf_map_iops)

		return ERR_PTR(-EINVAL);

	if (inode->i_op != &bpf_prog_iops)

		return ERR_PTR(-EACCES);



	prog = inode->i_private;



	ret = security_bpf_prog(prog);

	if (ret < 0)

		return ERR_PTR(ret);



	if (!bpf_prog_get_ok(prog, &type, false))

		return ERR_PTR(-EINVAL);



	return bpf_prog_inc(prog);

}



struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type)

{

	struct bpf_prog *prog;

	struct path path;

	int ret = kern_path(name, LOOKUP_FOLLOW, &path);

	if (ret)

		return ERR_PTR(ret);

	prog = __get_prog_inode(d_backing_inode(path.dentry), type);

	if (!IS_ERR(prog))

		touch_atime(&path);

	path_put(&path);

	return prog;

}

EXPORT_SYMBOL(bpf_prog_get_type_path);



static void bpf_evict_inode(struct inode *inode)

{

kernel/bpf/syscall.c

+1 −1
Original line number Diff line number Diff line
@@ -1057,7 +1057,7 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) 
}

EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);



static bool bpf_prog_get_ok(struct bpf_prog *prog,

bool bpf_prog_get_ok(struct bpf_prog *prog,

			    enum bpf_prog_type *attach_type, bool attach_drv)

{

	/* not an attachment, just a refcount inc, always allow */

net/netfilter/xt_bpf.c

+2 −12
Original line number Diff line number Diff line
@@ -52,18 +52,8 @@ static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret) 


static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)

{

	mm_segment_t oldfs = get_fs();

	int retval, fd;



	set_fs(KERNEL_DS);

	fd = bpf_obj_get_user(path, 0);

	set_fs(oldfs);

	if (fd < 0)

		return fd;



	retval = __bpf_mt_check_fd(fd, ret);

	sys_close(fd);

	return retval;

	*ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);

	return PTR_ERR_OR_ZERO(*ret);

}



static int bpf_mt_check(const struct xt_mtchk_param *par)