Re: [PATCH v2] bpf: Fix integer overflow involving bucket_size

Hello:

This patch was applied to bpf/bpf.git (refs/heads/master):

On Sat,  7 Aug 2021 00:04:18 +0900 you wrote:

In __htab_map_lookup_and_delete_batch(), hash buckets are iterated over
to count the number of elements in each bucket (bucket_size).
If bucket_size is large enough, the multiplication to calculate
kvmalloc() size could overflow, resulting in out-of-bounds write
as reported by KASAN.

[...]
[  104.986052] BUG: KASAN: vmalloc-out-of-bounds in __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[  104.986489] Write of size 4194224 at addr ffffc9010503be70 by task crash/112
[  104.986889]
[  104.987193] CPU: 0 PID: 112 Comm: crash Not tainted 5.14.0-rc4 #13
[  104.987552] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[  104.988104] Call Trace:
[  104.988410]  dump_stack_lvl+0x34/0x44
[  104.988706]  print_address_description.constprop.0+0x21/0x140
[  104.988991]  ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[  104.989327]  ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[  104.989622]  kasan_report.cold+0x7f/0x11b
[  104.989881]  ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[  104.990239]  kasan_check_range+0x17c/0x1e0
[  104.990467]  memcpy+0x39/0x60
[  104.990670]  __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[  104.990982]  ? __wake_up_common+0x4d/0x230
[  104.991256]  ? htab_of_map_free+0x130/0x130
[  104.991541]  bpf_map_do_batch+0x1fb/0x220
[...]

[...]

Here is the summary with links:
  - [v2] bpf: Fix integer overflow involving bucket_size
    https://git.kernel.org/bpf/bpf/c/ccd37ad9ef0a

You are awesome, thank you!
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