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When gmin_get_config_var() calls efi.get_variable() and the EFI variable
is larger than the expected buffer size, two behaviors combine to create
a stack buffer overflow:
1. gmin_get_config_var() does not return the proper error code when
efi.get_variable() fails. It returns the stale 'ret' value from
earlier operations instead of indicating the EFI failure.
2. When efi.get_variable() returns EFI_BUFFER_TOO_SMALL, it updates
*out_len to the required buffer size but writes no data to the output
buffer. However, due to bug #1, gmin_get_var_int() believes the call
succeeded.
The caller gmin_get_var_int() then performs:
- Allocates val[CFG_VAR_NAME_MAX + 1] (65 bytes) on stack
- Calls gmin_get_config_var(dev, is_gmin, var, val, &len) with len=64
- If EFI variable is >64 bytes, efi.get_variable() sets len=required_size
- Due to bug #1, thinks call succeeded with len=required_size
- Executes val[len] = 0, writing past end of 65-byte stack buffer
This creates a stack buffer overflow when EFI variables are larger than
64 bytes. Since EFI variables can be controlled by firmware or system
configuration, this could potentially be exploited for code execution.
Fix the bug by returning proper error codes from gmin_get_config_var()
based on EFI status instead of stale 'ret' value.
The gmin_get_var_int() function is called during device initialization
for camera sensor configuration on Intel Bay Trail and Cherry Trail
platforms using the atomisp camera stack.
Reported-by: zepta <z3ptaa@gmail.com>
Closes: https://lore.kernel.org/all/CAPBS6KoQyM7FMdPwOuXteXsOe44X4H3F8Fw+y_qWq6E+OdmxQA@mail.gmail.com
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.