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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
	Viacheslav Dubeyko <slava@dubeyko.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 11/38] hfs: fix high memory mapping in hfs_bnode_read
Date: Mon,  2 Aug 2021 15:44:33 +0200	[thread overview]
Message-ID: <20210802134335.194231488@linuxfoundation.org> (raw)
In-Reply-To: <20210802134334.835358048@linuxfoundation.org>

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

[ Upstream commit 54a5ead6f5e2b47131a7385d0c0af18e7b89cb02 ]

Pages that we read in hfs_bnode_read need to be kmapped into kernel
address space.  However, currently only the 0th page is kmapped.  If the
given offset + length exceeds this 0th page, then we have an invalid
memory access.

To fix this, we kmap relevant pages one by one and copy their relevant
portions of data.

An example of invalid memory access occurring without this fix can be seen
in the following crash report:

  ==================================================================
  BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:191 [inline]
  BUG: KASAN: use-after-free in hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26
  Read of size 2 at addr ffff888125fdcffe by task syz-executor5/4634

  CPU: 0 PID: 4634 Comm: syz-executor5 Not tainted 5.13.0-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:79 [inline]
   dump_stack+0x195/0x1f8 lib/dump_stack.c:120
   print_address_description.constprop.0+0x1d/0x110 mm/kasan/report.c:233
   __kasan_report mm/kasan/report.c:419 [inline]
   kasan_report.cold+0x7b/0xd4 mm/kasan/report.c:436
   check_region_inline mm/kasan/generic.c:180 [inline]
   kasan_check_range+0x154/0x1b0 mm/kasan/generic.c:186
   memcpy+0x24/0x60 mm/kasan/shadow.c:65
   memcpy include/linux/fortify-string.h:191 [inline]
   hfs_bnode_read+0xc4/0xe0 fs/hfs/bnode.c:26
   hfs_bnode_read_u16 fs/hfs/bnode.c:34 [inline]
   hfs_bnode_find+0x880/0xcc0 fs/hfs/bnode.c:365
   hfs_brec_find+0x2d8/0x540 fs/hfs/bfind.c:126
   hfs_brec_read+0x27/0x120 fs/hfs/bfind.c:165
   hfs_cat_find_brec+0x19a/0x3b0 fs/hfs/catalog.c:194
   hfs_fill_super+0xc13/0x1460 fs/hfs/super.c:419
   mount_bdev+0x331/0x3f0 fs/super.c:1368
   hfs_mount+0x35/0x40 fs/hfs/super.c:457
   legacy_get_tree+0x10c/0x220 fs/fs_context.c:592
   vfs_get_tree+0x93/0x300 fs/super.c:1498
   do_new_mount fs/namespace.c:2905 [inline]
   path_mount+0x13f5/0x20e0 fs/namespace.c:3235
   do_mount fs/namespace.c:3248 [inline]
   __do_sys_mount fs/namespace.c:3456 [inline]
   __se_sys_mount fs/namespace.c:3433 [inline]
   __x64_sys_mount+0x2b8/0x340 fs/namespace.c:3433
   do_syscall_64+0x37/0xc0 arch/x86/entry/common.c:47
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  RIP: 0033:0x45e63a
  Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 88 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
  RSP: 002b:00007f9404d410d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
  RAX: ffffffffffffffda RBX: 0000000020000248 RCX: 000000000045e63a
  RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f9404d41120
  RBP: 00007f9404d41120 R08: 00000000200002c0 R09: 0000000020000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
  R13: 0000000000000003 R14: 00000000004ad5d8 R15: 0000000000000000

  The buggy address belongs to the page:
  page:00000000dadbcf3e refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x125fdc
  flags: 0x2fffc0000000000(node=0|zone=2|lastcpupid=0x3fff)
  raw: 02fffc0000000000 ffffea000497f748 ffffea000497f6c8 0000000000000000
  raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888125fdce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff888125fdcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  >ffff888125fdcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                  ^
   ffff888125fdd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
   ffff888125fdd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
  ==================================================================

Link: https://lkml.kernel.org/r/20210701030756.58760-3-desmondcheongzx@gmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/bnode.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c
index 8aec5e732abf..bca3ea4137ee 100644
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -15,16 +15,31 @@
 
 #include "btree.h"
 
-void hfs_bnode_read(struct hfs_bnode *node, void *buf,
-		int off, int len)
+void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
 {
 	struct page *page;
+	int pagenum;
+	int bytes_read;
+	int bytes_to_read;
+	void *vaddr;
 
 	off += node->page_offset;
-	page = node->page[0];
+	pagenum = off >> PAGE_SHIFT;
+	off &= ~PAGE_MASK; /* compute page offset for the first page */
 
-	memcpy(buf, kmap(page) + off, len);
-	kunmap(page);
+	for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) {
+		if (pagenum >= node->tree->pages_per_bnode)
+			break;
+		page = node->page[pagenum];
+		bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
+
+		vaddr = kmap_atomic(page);
+		memcpy(buf + bytes_read, vaddr + off, bytes_to_read);
+		kunmap_atomic(vaddr);
+
+		pagenum++;
+		off = 0; /* page offset only applies to the first page */
+	}
 }
 
 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
-- 
2.30.2




  parent reply	other threads:[~2021-08-02 13:51 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:44 [PATCH 4.14 00/38] 4.14.242-rc1 review Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 01/38] selftest: fix build error in tools/testing/selftests/vm/userfaultfd.c Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 02/38] KVM: x86: determine if an exception has an error code only when injecting it Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 03/38] net: split out functions related to registering inflight socket files Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 04/38] af_unix: fix garbage collect vs MSG_PEEK Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 05/38] workqueue: fix UAF in pwq_unbound_release_workfn() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 06/38] net/802/mrp: fix memleak in mrp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 07/38] net/802/garp: fix memleak in garp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 08/38] net: annotate data race around sk_ll_usec Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 09/38] sctp: move 198 addresses from unusable to private scope Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 10/38] hfs: add missing clean-up in hfs_fill_super Greg Kroah-Hartman
2021-08-02 13:44 ` Greg Kroah-Hartman [this message]
2021-08-02 13:44 ` [PATCH 4.14 12/38] hfs: add lock nesting notation to hfs_find_init Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 13/38] ARM: dts: versatile: Fix up interrupt controller node names Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 14/38] virtio_net: Do not pull payload in skb->head Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 15/38] gro: ensure frag0 meets IP header alignment Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 16/38] x86/kvm: fix vcpu-id indexed array sizes Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 17/38] ocfs2: fix zero out valid data Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 18/38] ocfs2: issue zeroout to EOF blocks Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 19/38] can: raw: raw_setsockopt(): fix raw_rcv panic for sock UAF Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 20/38] can: mcba_usb_start(): add missing urb->transfer_dma initialization Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 21/38] can: usb_8dev: fix memory leak Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 22/38] can: ems_usb: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 23/38] can: esd_usb2: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 24/38] NIU: fix incorrect error return, missed in previous revert Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 25/38] nfc: nfcsim: fix use after free during module unload Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 26/38] x86/asm: Ensure asm/proto.h can be included stand-alone Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 27/38] cfg80211: Fix possible memory leak in function cfg80211_bss_update Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 28/38] netfilter: conntrack: adjust stop timestamp to real expiry value Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 29/38] netfilter: nft_nat: allow to specify layer 4 protocol NAT only Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 30/38] tipc: fix sleeping in tipc accept routine Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 31/38] mlx4: Fix missing error code in mlx4_load_one() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 32/38] net: llc: fix skb_over_panic Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 33/38] net/mlx5: Fix flow table chaining Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 34/38] sctp: fix return value check in __sctp_rcv_asconf_lookup Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 35/38] tulip: windbond-840: Fix missing pci_disable_device() in probe and remove Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 36/38] sis900: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 37/38] can: hi311x: fix a signedness bug in hi3110_cmd() Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 4.14 38/38] Revert "perf map: Fix dso->nsinfo refcounting" Greg Kroah-Hartman
2021-08-03 13:17 ` [PATCH 4.14 00/38] 4.14.242-rc1 review Naresh Kamboju
2021-08-03 19:15 ` Guenter Roeck
2021-08-04  2:56 ` Samuel Zou

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