diff options
| author | Hou Tao <houtao1@huawei.com> | 2022-11-16 08:23:50 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2022-11-18 00:49:39 +0100 |
| commit | 64176bff2446cd825b163976ee451fb6e5cd851d (patch) | |
| tree | ce7ea47216f9fb50875065ea9e850d5e1f6975b9 /tools/lib | |
| parent | libbpf: Handle size overflow for ringbuf mmap (diff) | |
| download | linux-64176bff2446cd825b163976ee451fb6e5cd851d.tar.xz linux-64176bff2446cd825b163976ee451fb6e5cd851d.zip | |
libbpf: Handle size overflow for user ringbuf mmap
Similar with the overflow problem on ringbuf mmap, in user_ringbuf_map()
2 * max_entries may overflow u32 when mapping writeable region.
Fixing it by casting the size of writable mmap region into a __u64 and
checking whether or not there will be overflow during mmap.
Fixes: b66ccae01f1d ("bpf: Add libbpf logic for user-space ring buffer")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221116072351.1168938-4-houtao@huaweicloud.com
Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/bpf/ringbuf.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 8d26684f3f00..5c4401cac1db 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -352,6 +352,7 @@ static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd) { struct bpf_map_info info; __u32 len = sizeof(info); + __u64 mmap_sz; void *tmp; struct epoll_event *rb_epoll; int err; @@ -388,8 +389,13 @@ static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd) * simple reading and writing of samples that wrap around the end of * the buffer. See the kernel implementation for details. */ - tmp = mmap(NULL, rb->page_size + 2 * info.max_entries, - PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, rb->page_size); + mmap_sz = rb->page_size + 2 * (__u64)info.max_entries; + if (mmap_sz != (__u64)(size_t)mmap_sz) { + pr_warn("user ringbuf: ring buf size (%u) is too big\n", info.max_entries); + return -E2BIG; + } + tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED, + map_fd, rb->page_size); if (tmp == MAP_FAILED) { err = -errno; pr_warn("user ringbuf: failed to mmap data pages for map fd=%d: %d\n", |