bpf: move memory size checks to bpf_map_charge_init()

Most bpf map types doing similar checks and bytes to pages
conversion during memory allocation and charging.

Let's unify these checks by moving them into bpf_map_charge_init().

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4a5ebad99154..4c53cbd3329d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -205,11 +205,16 @@ static void bpf_uncharge_memlock(struct user_struct *user, u32 pages)
                 atomic_long_sub(pages, &user->locked_vm);
 }
 
-int bpf_map_charge_init(struct bpf_map_memory *mem, u32 pages)
+int bpf_map_charge_init(struct bpf_map_memory *mem, size_t size)
 {
-        struct user_struct *user = get_current_user();
+        u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT;
+        struct user_struct *user;
         int ret;
 
+        if (size >= U32_MAX - PAGE_SIZE)
+                return -E2BIG;
+
+        user = get_current_user();
         ret = bpf_charge_memlock(user, pages);
         if (ret) {
                 free_uid(user);