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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: |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.