BACKPORT: bpf: Add file mode configuration into bpf maps
Introduce the map read/write flags to the eBPF syscalls that returns the
map fd. The flags is used to set up the file mode when construct a new
file descriptor for bpf maps. To not break the backward capability, the
f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise
it should be O_RDONLY or O_WRONLY. When the userspace want to modify or
read the map content, it will check the file mode to see if it is
allowed to make the change.
Signed-off-by: Chenbo Feng <fengc@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Deleted the file mode configuration code in unsupported map type and
removed the file mode check in non-existing helper functions.
(cherry-pick from net-next: 6e71b04a82248ccf13a94b85cbc674a9fefe53f5)
Bug: 30950746
Change-Id: Icfad20f1abb77f91068d244fb0d87fa40824dd1b
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index be85191..230aced 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -11,6 +11,9 @@
#include <linux/perf_event.h>
#include "percpu_freelist.h"
+#define STACK_CREATE_FLAG_MASK \
+ (BPF_F_RDONLY | BPF_F_WRONLY)
+
struct stack_map_bucket {
struct pcpu_freelist_node fnode;
u32 hash;
@@ -59,7 +62,7 @@
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
- if (attr->map_flags)
+ if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
/* check sanity of attributes */