linux-stable.git/net/bluetooth/hci_debugfs.c, branch linux-5.4.y

Bluetooth: Fix TOCTOU in HCI debugfs implementation

2024-04-13T10:51:33+00:00

commit 7835fcfd132eb88b87e8eb901f88436f63ab60f7 upstream.

struct hci_dev members conn_info_max_age, conn_info_min_age,
le_conn_max_interval, le_conn_min_interval, le_adv_max_interval,
and le_adv_min_interval can be modified from the HCI core code, as well
through debugfs.

The debugfs implementation, that's only available to privileged users,
will check for boundaries, making sure that the minimum value being set
is strictly above the maximum value that already exists, and vice-versa.

However, as both minimum and maximum values can be changed concurrently
to us modifying them, we need to make sure that the value we check is
the value we end up using.

For example, with ->conn_info_max_age set to 10, conn_info_min_age_set()
gets called from vfs handlers to set conn_info_min_age to 8.

In conn_info_min_age_set(), this goes through:
	if (val == 0 || val > hdev->conn_info_max_age)
		return -EINVAL;

Concurrently, conn_info_max_age_set() gets called to set to set the
conn_info_max_age to 7:
	if (val == 0 || val > hdev->conn_info_max_age)
		return -EINVAL;
That check will also pass because we used the old value (10) for
conn_info_max_age.

After those checks that both passed, the struct hci_dev access
is mutex-locked, disabling concurrent access, but that does not matter
because the invalid value checks both passed, and we'll end up with
conn_info_min_age = 8 and conn_info_max_age = 7

To fix this problem, we need to lock the structure access before so the
check and assignment are not interrupted.

This fix was originally devised by the BassCheck[1] team, and
considered the problem to be an atomicity one. This isn't the case as
there aren't any concerns about the variable changing while we check it,
but rather after we check it parallel to another change.

This patch fixes CVE-2024-24858 and CVE-2024-24857.

[1] https://sites.google.com/view/basscheck/

Co-developed-by: Gui-Dong Han <2045gemini@gmail.com>
Signed-off-by: Gui-Dong Han <2045gemini@gmail.com>
Link: https://lore.kernel.org/linux-bluetooth/20231222161317.6255-1-2045gemini@gmail.com/
Link: https://nvd.nist.gov/vuln/detail/CVE-2024-24858
Link: https://lore.kernel.org/linux-bluetooth/20231222162931.6553-1-2045gemini@gmail.com/
Link: https://lore.kernel.org/linux-bluetooth/20231222162310.6461-1-2045gemini@gmail.com/
Link: https://nvd.nist.gov/vuln/detail/CVE-2024-24857
Fixes: 31ad169148df ("Bluetooth: Add conn info lifetime parameters to debugfs")
Fixes: 729a1051da6f ("Bluetooth: Expose default LE advertising interval via debugfs")
Fixes: 71c3b60ec6d2 ("Bluetooth: Move BR/EDR debugfs file creation into hci_debugfs.c")
Signed-off-by: Bastien Nocera 
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: Add debug setting for changing minimum encryption key size

2019-08-17T10:54:40+00:00

For testing and qualification purposes it is useful to allow changing
the minimum encryption key size value that the host stack is going to
enforce. This adds a new debugfs setting min_encrypt_key_size to achieve
this functionality.

Signed-off-by: Marcel Holtmann 
Signed-off-by: Johan Hedberg

Bluetooth: Add support for LE ping feature

2019-07-06T13:29:12+00:00

Changes made to add HCI Write Authenticated Payload timeout
command for LE Ping feature.

As per the Core Specification 5.0 Volume 2 Part E Section 7.3.94,
the following code changes implements
HCI Write Authenticated Payload timeout command for LE Ping feature.

Signed-off-by: Spoorthi Ravishankar Koppad 
Signed-off-by: Marcel Holtmann

Bluetooth: Store Resolv list size

2018-07-06T10:40:08+00:00

When the controller supports the Read LE Resolv List size feature, the
maximum list size are read and now stored.

Before patch:
< HCI Command: LE Read White List... (0x08|0x000f) plen 0  #55 [hci0] 17.979791
> HCI Event: Command Complete (0x0e) plen 5                #56 [hci0] 17.980629
      LE Read White List Size (0x08|0x000f) ncmd 1
        Status: Success (0x00)
        Size: 25
< HCI Command: LE Clear White List (0x08|0x0010) plen 0    #57 [hci0] 17.980786
> HCI Event: Command Complete (0x0e) plen 4                #58 [hci0] 17.981627
      LE Clear White List (0x08|0x0010) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Read Maximum Dat.. (0x08|0x002f) plen 0  #59 [hci0] 17.981786
> HCI Event: Command Complete (0x0e) plen 12               #60 [hci0] 17.982636
      LE Read Maximum Data Length (0x08|0x002f) ncmd 1
        Status: Success (0x00)
        Max TX octets: 251
        Max TX time: 17040
        Max RX octets: 251
        Max RX time: 17040

After patch:
< HCI Command: LE Read White List... (0x08|0x000f) plen 0  #55 [hci0] 13.338168
> HCI Event: Command Complete (0x0e) plen 5                #56 [hci0] 13.338842
      LE Read White List Size (0x08|0x000f) ncmd 1
        Status: Success (0x00)
        Size: 25
< HCI Command: LE Clear White List (0x08|0x0010) plen 0    #57 [hci0] 13.339029
> HCI Event: Command Complete (0x0e) plen 4                #58 [hci0] 13.339939
      LE Clear White List (0x08|0x0010) ncmd 1
        Status: Success (0x00)
< HCI Command: LE Read Resolving L.. (0x08|0x002a) plen 0  #59 [hci0] 13.340152
> HCI Event: Command Complete (0x0e) plen 5                #60 [hci0] 13.340952
      LE Read Resolving List Size (0x08|0x002a) ncmd 1
        Status: Success (0x00)
        Size: 25
< HCI Command: LE Read Maximum Dat.. (0x08|0x002f) plen 0  #61 [hci0] 13.341180
> HCI Event: Command Complete (0x0e) plen 12               #62 [hci0] 13.341898
      LE Read Maximum Data Length (0x08|0x002f) ncmd 1
        Status: Success (0x00)
        Max TX octets: 251
        Max TX time: 17040
        Max RX octets: 251
        Max RX time: 17040

Signed-off-by: Ankit Navik 
Signed-off-by: Marcel Holtmann

Bluetooth: Re-use kstrtobool_from_user()

2018-05-30T06:16:04+00:00

Re-use kstrtobool_from_user() instead of open coded variant.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Marcel Holtmann

seq_file: Introduce DEFINE_SHOW_ATTRIBUTE() helper macro

2018-02-07T10:50:21+00:00

The DEFINE_SHOW_ATTRIBUTE() helper macro would be useful for current
users, which are many of them, and for new comers to decrease code
duplication.

Acked-by: Lee Jones 
Acked-by: Darren Hart (VMware) 
Signed-off-by: Andy Shevchenko

Bluetooth: introduce DEFINE_SHOW_ATTRIBUTE() macro

2017-12-13T19:20:34+00:00

This macro deduplicates a lot of similar code across the hci_debugfs.c
module. Targeting to be moved to seq_file.h eventually.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Marcel Holtmann

Bluetooth: Utilize %*ph specifier

2017-12-12T23:28:42+00:00

Instead of open coding byte-by-byte printing, re-use %*ph specifier.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Marcel Holtmann

Bluetooth: Add debugfs fields for hardware and firmware info

2016-07-18T06:33:28+00:00

Some Bluetooth controllers allow for reading hardware and firmware
related vendor specific infos. If they are available, then they can be
exposed via debugfs now.

Signed-off-by: Marcel Holtmann 
Signed-off-by: Johan Hedberg

Bluetooth: Expose current Device ID information via debugfs

2015-04-02T05:40:35+00:00

For debugging purposes it is good to be able to read the current
configured Device ID details.

Signed-off-by: Marcel Holtmann 
Signed-off-by: Johan Hedberg