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authorBjörn Töpel <bjorn.topel@intel.com>2019-10-29 16:43:07 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2019-10-31 21:41:33 +0100
commitff1c08e1f74b6864854c39be48aa799a6a2e4d2b (patch)
tree7d4474d2002747c76fcc5b312d60bbd59edd59f5 /kernel
parent04ec044b7d30800296824783df7d9728d16d7567 (diff)
downloadlinux-ff1c08e1f74b6864854c39be48aa799a6a2e4d2b.tar.bz2
bpf: Change size to u64 for bpf_map_{area_alloc, charge_init}()
The functions bpf_map_area_alloc() and bpf_map_charge_init() prior this commit passed the size parameter as size_t. In this commit this is changed to u64. All users of these functions avoid size_t overflows on 32-bit systems, by explicitly using u64 when calculating the allocation size and memory charge cost. However, since the result was narrowed by the size_t when passing size and cost to the functions, the overflow handling was in vain. Instead of changing all call sites to size_t and handle overflow at the call site, the parameter is changed to u64 and checked in the functions above. Fixes: d407bd25a204 ("bpf: don't trigger OOM killer under pressure with map alloc") Fixes: c85d69135a91 ("bpf: move memory size checks to bpf_map_charge_init()") Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Link: https://lore.kernel.org/bpf/20191029154307.23053-1-bjorn.topel@gmail.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/syscall.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0937719b87e2..ace1cfaa24b6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -126,7 +126,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
return map;
}
-void *bpf_map_area_alloc(size_t size, int numa_node)
+void *bpf_map_area_alloc(u64 size, int numa_node)
{
/* We really just want to fail instead of triggering OOM killer
* under memory pressure, therefore we set __GFP_NORETRY to kmalloc,
@@ -141,6 +141,9 @@ void *bpf_map_area_alloc(size_t size, int numa_node)
const gfp_t flags = __GFP_NOWARN | __GFP_ZERO;
void *area;
+ if (size >= SIZE_MAX)
+ return NULL;
+
if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
area = kmalloc_node(size, GFP_USER | __GFP_NORETRY | flags,
numa_node);
@@ -197,7 +200,7 @@ 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, size_t size)
+int bpf_map_charge_init(struct bpf_map_memory *mem, u64 size)
{
u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT;
struct user_struct *user;