From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Yoon Jungyeon <jungyeon@gatech.edu>,
Nikolay Borisov <nborisov@suse.com>, Qu Wenruo <wqu@suse.com>,
David Sterba <dsterba@suse.com>,
Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Subject: [PATCH 4.9 06/42] btrfs: inode: Verify inode mode to avoid NULL pointer dereference
Date: Tue, 1 Dec 2020 09:53:04 +0100 [thread overview]
Message-ID: <20201201084642.477500696@linuxfoundation.org> (raw)
In-Reply-To: <20201201084642.194933793@linuxfoundation.org>
From: Qu Wenruo <wqu@suse.com>
commit 6bf9e4bd6a277840d3fe8c5d5d530a1fbd3db592 upstream
[BUG]
When accessing a file on a crafted image, btrfs can crash in block layer:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
PGD 136501067 P4D 136501067 PUD 124519067 PMD 0
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.0.0-rc8-default #252
RIP: 0010:end_bio_extent_readpage+0x144/0x700
Call Trace:
<IRQ>
blk_update_request+0x8f/0x350
blk_mq_end_request+0x1a/0x120
blk_done_softirq+0x99/0xc0
__do_softirq+0xc7/0x467
irq_exit+0xd1/0xe0
call_function_single_interrupt+0xf/0x20
</IRQ>
RIP: 0010:default_idle+0x1e/0x170
[CAUSE]
The crafted image has a tricky corruption, the INODE_ITEM has a
different type against its parent dir:
item 20 key (268 INODE_ITEM 0) itemoff 2808 itemsize 160
generation 13 transid 13 size 1048576 nbytes 1048576
block group 0 mode 121644 links 1 uid 0 gid 0 rdev 0
sequence 9 flags 0x0(none)
This mode number 0120000 means it's a symlink.
But the dir item think it's still a regular file:
item 8 key (264 DIR_INDEX 5) itemoff 3707 itemsize 32
location key (268 INODE_ITEM 0) type FILE
transid 13 data_len 0 name_len 2
name: f4
item 40 key (264 DIR_ITEM 51821248) itemoff 1573 itemsize 32
location key (268 INODE_ITEM 0) type FILE
transid 13 data_len 0 name_len 2
name: f4
For symlink, we don't set BTRFS_I(inode)->io_tree.ops and leave it
empty, as symlink is only designed to have inlined extent, all handled
by tree block read. Thus no need to trigger btrfs_submit_bio_hook() for
inline file extent.
However end_bio_extent_readpage() expects tree->ops populated, as it's
reading regular data extent. This causes NULL pointer dereference.
[FIX]
This patch fixes the problem in two ways:
- Verify inode mode against its dir item when looking up inode
So in btrfs_lookup_dentry() if we find inode mode mismatch with dir
item, we error out so that corrupted inode will not be accessed.
- Verify inode mode when getting extent mapping
Only regular file should have regular or preallocated extent.
If we found regular/preallocated file extent for symlink or
the rest, we error out before submitting the read bio.
With this fix that crafted image can be rejected gracefully:
BTRFS critical (device loop0): inode mode mismatch with dir: inode mode=0121644 btrfs type=7 dir type=1
Reported-by: Yoon Jungyeon <jungyeon@gatech.edu>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202763
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[sudip: use original btrfs_inode_type(), btrfs_crit with root->fs_info,
ISREG with inode->i_mode and adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/btrfs/inode.c | 41 +++++++++++++++++++++++++++++++++--------
fs/btrfs/tests/inode-tests.c | 1 +
2 files changed, 34 insertions(+), 8 deletions(-)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5440,11 +5440,13 @@ no_delete:
}
/*
- * this returns the key found in the dir entry in the location pointer.
+ * Return the key found in the dir entry in the location pointer, fill @type
+ * with BTRFS_FT_*, and return 0.
+ *
* If no dir entries were found, location->objectid is 0.
*/
static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
- struct btrfs_key *location)
+ struct btrfs_key *location, u8 *type)
{
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
@@ -5466,6 +5468,8 @@ static int btrfs_inode_by_name(struct in
goto out_err;
btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
+ if (!ret)
+ *type = btrfs_dir_type(path->nodes[0], di);
out:
btrfs_free_path(path);
return ret;
@@ -5755,19 +5759,25 @@ static struct inode *new_simple_dir(stru
return inode;
}
+static inline u8 btrfs_inode_type(struct inode *inode)
+{
+ return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
+}
+
struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
{
struct inode *inode;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_root *sub_root = root;
struct btrfs_key location;
+ u8 di_type = 0;
int index;
int ret = 0;
if (dentry->d_name.len > BTRFS_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
- ret = btrfs_inode_by_name(dir, dentry, &location);
+ ret = btrfs_inode_by_name(dir, dentry, &location, &di_type);
if (ret < 0)
return ERR_PTR(ret);
@@ -5776,6 +5786,18 @@ struct inode *btrfs_lookup_dentry(struct
if (location.type == BTRFS_INODE_ITEM_KEY) {
inode = btrfs_iget(dir->i_sb, &location, root, NULL);
+ if (IS_ERR(inode))
+ return inode;
+
+ /* Do extra check against inode mode with di_type */
+ if (btrfs_inode_type(inode) != di_type) {
+ btrfs_crit(root->fs_info,
+"inode mode mismatch with dir: inode mode=0%o btrfs type=%u dir type=%u",
+ inode->i_mode, btrfs_inode_type(inode),
+ di_type);
+ iput(inode);
+ return ERR_PTR(-EUCLEAN);
+ }
return inode;
}
@@ -6391,11 +6413,6 @@ fail:
return ERR_PTR(ret);
}
-static inline u8 btrfs_inode_type(struct inode *inode)
-{
- return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
-}
-
/*
* utility function to add 'inode' into 'parent_inode' with
* a give name and a given sequence number.
@@ -6981,6 +6998,14 @@ again:
extent_start = found_key.offset;
if (found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+ /* Only regular file could have regular/prealloc extent */
+ if (!S_ISREG(inode->i_mode)) {
+ ret = -EUCLEAN;
+ btrfs_crit(root->fs_info,
+ "regular/prealloc extent found for non-regular inode %llu",
+ btrfs_ino(inode));
+ goto out;
+ }
extent_end = extent_start +
btrfs_file_extent_num_bytes(leaf, item);
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
--- a/fs/btrfs/tests/inode-tests.c
+++ b/fs/btrfs/tests/inode-tests.c
@@ -245,6 +245,7 @@ static noinline int test_btrfs_get_exten
return ret;
}
+ inode->i_mode = S_IFREG;
BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
BTRFS_I(inode)->location.objectid = BTRFS_FIRST_FREE_OBJECTID;
BTRFS_I(inode)->location.offset = 0;
next prev parent reply other threads:[~2020-12-01 8:56 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 8:52 [PATCH 4.9 00/42] 4.9.247-rc1 review Greg Kroah-Hartman
2020-12-01 8:52 ` [PATCH 4.9 01/42] perf event: Check ref_reloc_sym before using it Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 02/42] mm/userfaultfd: do not access vma->vm_mm after calling handle_userfault() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 03/42] btrfs: fix lockdep splat when reading qgroup config on mount Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 04/42] PCI: Add device even if driver attach failed Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 05/42] btrfs: tree-checker: Enhance chunk checker to validate chunk profile Greg Kroah-Hartman
2020-12-01 8:53 ` Greg Kroah-Hartman [this message]
2020-12-01 8:53 ` [PATCH 4.9 07/42] KVM: x86: Fix split-irqchip vs interrupt injection window request Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 08/42] arm64: pgtable: Fix pte_accessible() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 09/42] ALSA: hda/hdmi: Use single mutex unlock in error paths Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 10/42] ALSA: hda/hdmi: fix incorrect locking in hdmi_pcm_close Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 11/42] HID: cypress: Support Varmilo Keyboards media hotkeys Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 12/42] Input: i8042 - allow insmod to succeed on devices without an i8042 controller Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 13/42] HID: hid-sensor-hub: Fix issue with devices with no report ID Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 14/42] dmaengine: xilinx_dma: use readl_poll_timeout_atomic variant Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 15/42] x86/xen: dont unbind uninitialized lock_kicker_irq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 16/42] proc: dont allow async path resolution of /proc/self components Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 17/42] dmaengine: pl330: _prep_dma_memcpy: Fix wrong burst size Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 18/42] scsi: libiscsi: Fix NOP race condition Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 19/42] scsi: target: iscsi: Fix cmd abort fabric stop race Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 20/42] perf/x86: fix sysfs type mismatches Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 21/42] phy: tegra: xusb: Fix dangling pointer on probe failure Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 22/42] batman-adv: set .owner to THIS_MODULE Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 23/42] scsi: ufs: Fix race between shutdown and runtime resume flow Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 24/42] bnxt_en: fix error return code in bnxt_init_board() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 25/42] video: hyperv_fb: Fix the cache type when mapping the VRAM Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 26/42] bnxt_en: Release PCI regions when DMA mask setup fails during probe Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 27/42] IB/mthca: fix return value of error branch in mthca_init_cq() Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 28/42] nfc: s3fwrn5: use signed integer for parsing GPIO numbers Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 29/42] net: ena: set initial DMA width to avoid intel iommu issue Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 30/42] ibmvnic: fix NULL pointer dereference in ibmvic_reset_crq Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 31/42] efivarfs: revert "fix memory leak in efivarfs_create()" Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 32/42] can: gs_usb: fix endianess problem with candleLight firmware Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 33/42] platform/x86: toshiba_acpi: Fix the wrong variable assignment Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 34/42] perf probe: Fix to die_entrypc() returns error correctly Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 35/42] USB: core: Change %pK for __user pointers to %px Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 36/42] usb: gadget: f_midi: Fix memleak in f_midi_alloc Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 37/42] usb: gadget: Fix memleak in gadgetfs_fill_super Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 38/42] x86/speculation: Fix prctl() when spectre_v2_user={seccomp,prctl},ibpb Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 39/42] regulator: avoid resolve_supply() infinite recursion Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 40/42] regulator: workaround self-referent regulators Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 41/42] USB: core: add endpoint-blacklist quirk Greg Kroah-Hartman
2020-12-01 8:53 ` [PATCH 4.9 42/42] USB: core: Fix regression in Hercules audio card Greg Kroah-Hartman
2020-12-01 21:39 ` [PATCH 4.9 00/42] 4.9.247-rc1 review Guenter Roeck
2020-12-02 6:14 ` Naresh Kamboju
2020-12-02 17:04 ` Shuah Khan
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