From patchwork Fri Nov 15 12:53:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Fijalkowski, Maciej" X-Patchwork-Id: 13876199 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A83DC1BCA19; Fri, 15 Nov 2024 12:54:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731675242; cv=none; b=bQQGCWSR+cEUJwuqa4Rzr7ZYT16w1ibImEmacsyU6tNhq/4c9p0Fjz3XBgB6biRphdZnXgQ+uvC3UErteMaXNV66DBI26l0wP8QXv7BcnvWRcwg7mr4YOaGx7XEPikNrvnYZSUY3qDpFfjwh6NtA6Q1OFIqvzn0wCJG84+Xn1i8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731675242; c=relaxed/simple; bh=5gLwRkHtra4mGAlh8DUhPfiM3IoHF+mWNPxUInl0EX0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=sWXQk48AygiEHbwGP3HLwukMY87mpYFSRphwPXTTCzZBkgk3bwhC+Evmv2Ljk6LzdRUAkNMBgGEVL0Th2Lvc48ULc0FSUZoUnzMJyAaTpjJoBQXaot5fzkvVxZBWUF5wVpX3wYF19sg2zEK1F7vv5iojNKpAntJCqXbY4nJRYnY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=jOapYzWi; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="jOapYzWi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1731675241; x=1763211241; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=5gLwRkHtra4mGAlh8DUhPfiM3IoHF+mWNPxUInl0EX0=; b=jOapYzWieXxA0rvPgiHhVwqpFMJF21vWITEDpJkKjs3bHV9h95HaF0P3 lPA1jHCYohOZ8ADUlTqz2msRclUiluJ2pWmTJhReWBak8dGcvy952pL1m NPPfxI4hKWxWptaPiEWBgc5VVb16OHi81bJd7mau83cy+jbbA15QAbDJj In4FZkBh4OuSao2FelaW8sb13KN9Qcg5NDPRwugMx7AnP8asUhzcar08J J5XP/tccEIm9b8PnTxBBNCDuVE4BMmqe2ovvBTMOa5cksOgpEvaScEfRF WJ9u/R5itvpmDeljOabpnZ7lPwQM5gxfvBzstIKTG0ot96a7YRq9ZPTdZ Q==; X-CSE-ConnectionGUID: 7RvZupg4QECznYiX6uXNXQ== X-CSE-MsgGUID: kQmlDM62QYSGZ5YT88OadQ== X-IronPort-AV: E=McAfee;i="6700,10204,11257"; a="35607632" X-IronPort-AV: E=Sophos;i="6.12,156,1728975600"; d="scan'208";a="35607632" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Nov 2024 04:54:00 -0800 X-CSE-ConnectionGUID: pPFwgR3TT1WgqDYAoWAE5w== X-CSE-MsgGUID: jBd7WpgJSBOt88dreyBQwA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,156,1728975600"; d="scan'208";a="88555497" Received: from boxer.igk.intel.com ([10.102.20.173]) by orviesa009.jf.intel.com with ESMTP; 15 Nov 2024 04:53:57 -0800 From: Maciej Fijalkowski To: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: netdev@vger.kernel.org, magnus.karlsson@intel.com, bjorn@kernel.org, maciej.fijalkowski@intel.com, jordyzomer@google.com, security@kernel.org Subject: [PATCH bpf 1/2] xsk: fix OOB map writes when deleting elements Date: Fri, 15 Nov 2024 13:53:47 +0100 Message-Id: <20241115125348.654145-2-maciej.fijalkowski@intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20241115125348.654145-1-maciej.fijalkowski@intel.com> References: <20241115125348.654145-1-maciej.fijalkowski@intel.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Jordy says: " In the xsk_map_delete_elem function an unsigned integer (map->max_entries) is compared with a user-controlled signed integer (k). Due to implicit type conversion, a large unsigned value for map->max_entries can bypass the intended bounds check: if (k >= map->max_entries) return -EINVAL; This allows k to hold a negative value (between -2147483648 and -2), which is then used as an array index in m->xsk_map[k], which results in an out-of-bounds access. spin_lock_bh(&m->lock); map_entry = &m->xsk_map[k]; // Out-of-bounds map_entry old_xs = unrcu_pointer(xchg(map_entry, NULL)); // Oob write if (old_xs) xsk_map_sock_delete(old_xs, map_entry); spin_unlock_bh(&m->lock); The xchg operation can then be used to cause an out-of-bounds write. Moreover, the invalid map_entry passed to xsk_map_sock_delete can lead to further memory corruption. " It indeed results in following splat: [76612.897343] BUG: unable to handle page fault for address: ffffc8fc2e461108 [76612.904330] #PF: supervisor write access in kernel mode [76612.909639] #PF: error_code(0x0002) - not-present page [76612.914855] PGD 0 P4D 0 [76612.917431] Oops: Oops: 0002 [#1] PREEMPT SMP [76612.921859] CPU: 11 UID: 0 PID: 10318 Comm: a.out Not tainted 6.12.0-rc1+ #470 [76612.929189] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [76612.939781] RIP: 0010:xsk_map_delete_elem+0x2d/0x60 [76612.944738] Code: 00 00 41 54 55 53 48 63 2e 3b 6f 24 73 38 4c 8d a7 f8 00 00 00 48 89 fb 4c 89 e7 e8 2d bf 05 00 48 8d b4 eb 00 01 00 00 31 ff <48> 87 3e 48 85 ff 74 05 e8 16 ff ff ff 4c 89 e7 e8 3e bc 05 00 31 [76612.963774] RSP: 0018:ffffc9002e407df8 EFLAGS: 00010246 [76612.969079] RAX: 0000000000000000 RBX: ffffc9002e461000 RCX: 0000000000000000 [76612.976323] RDX: 0000000000000001 RSI: ffffc8fc2e461108 RDI: 0000000000000000 [76612.983569] RBP: ffffffff80000001 R08: 0000000000000000 R09: 0000000000000007 [76612.990812] R10: ffffc9002e407e18 R11: ffff888108a38858 R12: ffffc9002e4610f8 [76612.998060] R13: ffff888108a38858 R14: 00007ffd1ae0ac78 R15: ffffc9002e4610c0 [76613.005303] FS: 00007f80b6f59740(0000) GS:ffff8897e0ec0000(0000) knlGS:0000000000000000 [76613.013517] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [76613.019349] CR2: ffffc8fc2e461108 CR3: 000000011e3ef001 CR4: 00000000007726f0 [76613.026595] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [76613.033841] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [76613.041086] PKRU: 55555554 [76613.043842] Call Trace: [76613.046331] [76613.048468] ? __die+0x20/0x60 [76613.051581] ? page_fault_oops+0x15a/0x450 [76613.055747] ? search_extable+0x22/0x30 [76613.059649] ? search_bpf_extables+0x5f/0x80 [76613.063988] ? exc_page_fault+0xa9/0x140 [76613.067975] ? asm_exc_page_fault+0x22/0x30 [76613.072229] ? xsk_map_delete_elem+0x2d/0x60 [76613.076573] ? xsk_map_delete_elem+0x23/0x60 [76613.080914] __sys_bpf+0x19b7/0x23c0 [76613.084555] __x64_sys_bpf+0x1a/0x20 [76613.088194] do_syscall_64+0x37/0xb0 [76613.091832] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [76613.096962] RIP: 0033:0x7f80b6d1e88d [76613.100592] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 b5 0f 00 f7 d8 64 89 01 48 [76613.119631] RSP: 002b:00007ffd1ae0ac68 EFLAGS: 00000206 ORIG_RAX: 0000000000000141 [76613.131330] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f80b6d1e88d [76613.142632] RDX: 0000000000000098 RSI: 00007ffd1ae0ad20 RDI: 0000000000000003 [76613.153967] RBP: 00007ffd1ae0adc0 R08: 0000000000000000 R09: 0000000000000000 [76613.166030] R10: 00007f80b6f77040 R11: 0000000000000206 R12: 00007ffd1ae0aed8 [76613.177130] R13: 000055ddf42ce1e9 R14: 000055ddf42d0d98 R15: 00007f80b6fab040 [76613.188129] Fix this by simply changing key type from int to u32. Fixes: fbfc504a24f5 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP") Reported-by: Jordy Zomer Suggested-by: Jordy Zomer Signed-off-by: Maciej Fijalkowski Reviewed-by: Toke Høiland-Jørgensen Acked-by: John Fastabend --- net/xdp/xskmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c index e1c526f97ce3..afa457506274 100644 --- a/net/xdp/xskmap.c +++ b/net/xdp/xskmap.c @@ -224,7 +224,7 @@ static long xsk_map_delete_elem(struct bpf_map *map, void *key) struct xsk_map *m = container_of(map, struct xsk_map, map); struct xdp_sock __rcu **map_entry; struct xdp_sock *old_xs; - int k = *(u32 *)key; + u32 k = *(u32 *)key; if (k >= map->max_entries) return -EINVAL; From patchwork Fri Nov 15 12:53:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Fijalkowski, Maciej" X-Patchwork-Id: 13876200 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CBDDC1BF81B; Fri, 15 Nov 2024 12:54:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731675245; cv=none; b=qOy4kWAWsVrqkfnfiuvFlrnOW18blv/tLV6PCxuQsAH/Xd8Pf4Zu5lTwj9N8miCRXFEcI2u+woeAb/vcq647Mt+QRljlIYE+5Je4eE9/g3F3iCiZE7cyMDDHGyIOAdfTtoMZbxVlsoVAcHsUuKqiI5j/SEwBAAB4AwcJZ3PGJt0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731675245; c=relaxed/simple; bh=Pq42jzca9zpHieZF+Q8ufniBF3oBct0bsuYex6yoMj0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=acjv54zJElCUXdXorpjqvZwQ8I2fkyW+4FpSv0eWThWcX3AK6cgUlD9lS9pUtUpaHy1GD9IrDv4YuZ5wbncTRtR3EtGB37TjoBeTUHQPmph3kx1HHKEPjZNvuGVllKN69UYgLj+u4rTmTFYiwp8W0COw4EWOYhuF6ejDJA1blUo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=QotLqi8m; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QotLqi8m" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1731675244; x=1763211244; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Pq42jzca9zpHieZF+Q8ufniBF3oBct0bsuYex6yoMj0=; b=QotLqi8mCvNkQutqAitmw4LP0JV7+7nqRN9mRIzze5uUI4H1M0rGztZA j4m6DBnQyDHapnI5fLehWDAhlSlF9dPWJhwmaLERNF8jqMkQq8/Y+nGLb tYDzQkgUeoO0QDwg2CEEnoB4CvA1XQsQfBcfWHkSClU6PBLd/7loDsyYP 6FRQDzdCVazXXrSm439t9WsfDHBOCYofRqql/agSpJBPMXqMaVCw47+G0 4TsMRkuQfuCyuP28Yc1G+y2aT5SBPFoxsTu6gR+GO+4G9wlE3UZAwRF8p ZGLiLrQNCFcMrG82OL/CtWBQOk5wHBmOP+s7YGpHPIBb4cV2RzJI8LK25 A==; X-CSE-ConnectionGUID: PqyiUaTpRqeg3cmRZeEcWw== X-CSE-MsgGUID: h89ZwyJvSfWcGsSigwAKKQ== X-IronPort-AV: E=McAfee;i="6700,10204,11257"; a="35607638" X-IronPort-AV: E=Sophos;i="6.12,156,1728975600"; d="scan'208";a="35607638" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Nov 2024 04:54:03 -0800 X-CSE-ConnectionGUID: HAUjZ+CuRuS7SVsLOg95sg== X-CSE-MsgGUID: fkX3wC/kTsy3nEohA3wlcQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,156,1728975600"; d="scan'208";a="88555517" Received: from boxer.igk.intel.com ([10.102.20.173]) by orviesa009.jf.intel.com with ESMTP; 15 Nov 2024 04:54:00 -0800 From: Maciej Fijalkowski To: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: netdev@vger.kernel.org, magnus.karlsson@intel.com, bjorn@kernel.org, maciej.fijalkowski@intel.com, jordyzomer@google.com, security@kernel.org Subject: [PATCH bpf 2/2] bpf: fix OOB devmap writes when deleting elements Date: Fri, 15 Nov 2024 13:53:48 +0100 Message-Id: <20241115125348.654145-3-maciej.fijalkowski@intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20241115125348.654145-1-maciej.fijalkowski@intel.com> References: <20241115125348.654145-1-maciej.fijalkowski@intel.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Jordy reported issue against XSKMAP which also applies to DEVMAP - the index used for accessing map entry, due to being a signed integer, causes the OOB writes. Fix is simple as changing the type from int to u32, however, when compared to XSKMAP case, one more thing needs to be addressed. When map is released from system via dev_map_free(), we iterate through all of the entries and an iterator variable is also an int, which implies OOB accesses. Again, change it to be u32. Example splat below: [ 160.724676] BUG: unable to handle page fault for address: ffffc8fc2c001000 [ 160.731662] #PF: supervisor read access in kernel mode [ 160.736876] #PF: error_code(0x0000) - not-present page [ 160.742095] PGD 0 P4D 0 [ 160.744678] Oops: Oops: 0000 [#1] PREEMPT SMP [ 160.749106] CPU: 1 UID: 0 PID: 520 Comm: kworker/u145:12 Not tainted 6.12.0-rc1+ #487 [ 160.757050] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [ 160.767642] Workqueue: events_unbound bpf_map_free_deferred [ 160.773308] RIP: 0010:dev_map_free+0x77/0x170 [ 160.777735] Code: 00 e8 fd 91 ed ff e8 b8 73 ed ff 41 83 7d 18 19 74 6e 41 8b 45 24 49 8b bd f8 00 00 00 31 db 85 c0 74 48 48 63 c3 48 8d 04 c7 <48> 8b 28 48 85 ed 74 30 48 8b 7d 18 48 85 ff 74 05 e8 b3 52 fa ff [ 160.796777] RSP: 0018:ffffc9000ee1fe38 EFLAGS: 00010202 [ 160.802086] RAX: ffffc8fc2c001000 RBX: 0000000080000000 RCX: 0000000000000024 [ 160.809331] RDX: 0000000000000000 RSI: 0000000000000024 RDI: ffffc9002c001000 [ 160.816576] RBP: 0000000000000000 R08: 0000000000000023 R09: 0000000000000001 [ 160.823823] R10: 0000000000000001 R11: 00000000000ee6b2 R12: dead000000000122 [ 160.831066] R13: ffff88810c928e00 R14: ffff8881002df405 R15: 0000000000000000 [ 160.838310] FS: 0000000000000000(0000) GS:ffff8897e0c40000(0000) knlGS:0000000000000000 [ 160.846528] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 160.852357] CR2: ffffc8fc2c001000 CR3: 0000000005c32006 CR4: 00000000007726f0 [ 160.859604] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 160.866847] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 160.874092] PKRU: 55555554 [ 160.876847] Call Trace: [ 160.879338] [ 160.881477] ? __die+0x20/0x60 [ 160.884586] ? page_fault_oops+0x15a/0x450 [ 160.888746] ? search_extable+0x22/0x30 [ 160.892647] ? search_bpf_extables+0x5f/0x80 [ 160.896988] ? exc_page_fault+0xa9/0x140 [ 160.900973] ? asm_exc_page_fault+0x22/0x30 [ 160.905232] ? dev_map_free+0x77/0x170 [ 160.909043] ? dev_map_free+0x58/0x170 [ 160.912857] bpf_map_free_deferred+0x51/0x90 [ 160.917196] process_one_work+0x142/0x370 [ 160.921272] worker_thread+0x29e/0x3b0 [ 160.925082] ? rescuer_thread+0x4b0/0x4b0 [ 160.929157] kthread+0xd4/0x110 [ 160.932355] ? kthread_park+0x80/0x80 [ 160.936079] ret_from_fork+0x2d/0x50 [ 160.943396] ? kthread_park+0x80/0x80 [ 160.950803] ret_from_fork_asm+0x11/0x20 [ 160.958482] Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references") Reported-by: Jordy Zomer Suggested-by: Jordy Zomer Signed-off-by: Maciej Fijalkowski Reviewed-by: Toke Høiland-Jørgensen Acked-by: John Fastabend --- kernel/bpf/devmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 7878be18e9d2..3aa002a47a96 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -184,7 +184,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) static void dev_map_free(struct bpf_map *map) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); - int i; + u32 i; /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, * so the programs (can be more than one that used this map) were @@ -821,7 +821,7 @@ static long dev_map_delete_elem(struct bpf_map *map, void *key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); struct bpf_dtab_netdev *old_dev; - int k = *(u32 *)key; + u32 k = *(u32 *)key; if (k >= map->max_entries) return -EINVAL; @@ -838,7 +838,7 @@ static long dev_map_hash_delete_elem(struct bpf_map *map, void *key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); struct bpf_dtab_netdev *old_dev; - int k = *(u32 *)key; + u32 k = *(u32 *)key; unsigned long flags; int ret = -ENOENT;