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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.

Al Viro committed 8 years ago

Commit 040ee691 parent 9ee332d4 files · +52 −14Browse files

Unified · Split

4 files
  1. include/linux/bpf.h +10 −0
  2. kernel/bpf/inode.c +39 −1
  3. kernel/bpf/syscall.c +1 −1
  4. net/netfilter/xt_bpf.c +2 −12
include/linux/bpf.h+10−0
@@ -419,6 +419,8 @@ static inline int bpf_map_attr_numa_node(const union bpf_attr *attr) · 418 unmodified lines
419419 attr->numa_node : NUMA_NO_NODE;
420420 }
421421
422+struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type);
423+
422424 #else /* !CONFIG_BPF_SYSCALL */
423425 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
424426 {
@@ -506,6 +508,12 @@ static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, · 81 unmodified lines
506508 {
507509 return 0;
508510 }
511+
512+static inline struct bpf_prog *bpf_prog_get_type_path(const char *name,
513+ enum bpf_prog_type type)
514+{
515+ return ERR_PTR(-EOPNOTSUPP);
516+}
509517 #endif /* CONFIG_BPF_SYSCALL */
510518
511519 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, · 2 unmodified lines
514522 return bpf_prog_get_type_dev(ufd, type, false);
515523 }
516524
525+bool bpf_prog_get_ok(struct bpf_prog *, enum bpf_prog_type *, bool);
526+
517527 int bpf_prog_offload_compile(struct bpf_prog *prog);
518528 void bpf_prog_offload_destroy(struct bpf_prog *prog);
519529
kernel/bpf/inode.c+39−1
@@ -368,7 +368,45 @@ out: · 367 unmodified lines
368368 putname(pname);
369369 return ret;
370370 }
371−EXPORT_SYMBOL_GPL(bpf_obj_get_user);
371+
372+static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)
373+{
374+ struct bpf_prog *prog;
375+ int ret = inode_permission(inode, MAY_READ | MAY_WRITE);
376+ if (ret)
377+ return ERR_PTR(ret);
378+
379+ if (inode->i_op == &bpf_map_iops)
380+ return ERR_PTR(-EINVAL);
381+ if (inode->i_op != &bpf_prog_iops)
382+ return ERR_PTR(-EACCES);
383+
384+ prog = inode->i_private;
385+
386+ ret = security_bpf_prog(prog);
387+ if (ret < 0)
388+ return ERR_PTR(ret);
389+
390+ if (!bpf_prog_get_ok(prog, &type, false))
391+ return ERR_PTR(-EINVAL);
392+
393+ return bpf_prog_inc(prog);
394+}
395+
396+struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type)
397+{
398+ struct bpf_prog *prog;
399+ struct path path;
400+ int ret = kern_path(name, LOOKUP_FOLLOW, &path);
401+ if (ret)
402+ return ERR_PTR(ret);
403+ prog = __get_prog_inode(d_backing_inode(path.dentry), type);
404+ if (!IS_ERR(prog))
405+ touch_atime(&path);
406+ path_put(&path);
407+ return prog;
408+}
409+EXPORT_SYMBOL(bpf_prog_get_type_path);
372410
373411 static void bpf_evict_inode(struct inode *inode)
374412 {
kernel/bpf/syscall.c+1−1
@@ -1057,7 +1057,7 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) · 1056 unmodified lines
10571057 }
10581058 EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
10591059
1060−static bool bpf_prog_get_ok(struct bpf_prog *prog,
1060+bool bpf_prog_get_ok(struct bpf_prog *prog,
10611061 enum bpf_prog_type *attach_type, bool attach_drv)
10621062 {
10631063 /* not an attachment, just a refcount inc, always allow */
net/netfilter/xt_bpf.c+2−12
@@ -52,18 +52,8 @@ static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret) · 51 unmodified lines
5252
5353 static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
5454 {
55− mm_segment_t oldfs = get_fs();
56− int retval, fd;
57−
58− set_fs(KERNEL_DS);
59− fd = bpf_obj_get_user(path, 0);
60− set_fs(oldfs);
61− if (fd < 0)
62− return fd;
63−
64− retval = __bpf_mt_check_fd(fd, ret);
65− sys_close(fd);
66− return retval;
55+ *ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
56+ return PTR_ERR_OR_ZERO(*ret);
6757 }
6858
6959 static int bpf_mt_check(const struct xt_mtchk_param *par)