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The commit91fb02f315("module: Move kallsyms support into a separate file") changed from using strlcpy() to using strscpy() which created a buffer overflow. That happened because: 1) an incorrect value was passed as the buffer length 2) strscpy() (unlike strlcpy()) may copy beyond the length of the input string when copying word-by-word. The assumption was that because it was already known that the strings being copied would fit in the space available, it was not necessary to correctly set the buffer length. strscpy() breaks that assumption because although it will not touch bytes beyond the given buffer length it may write bytes beyond the input string length when writing word-by-word. The result of the buffer overflow is to corrupt the symbol type information that follows. e.g. $ sudo cat -v /proc/kallsyms | grep '\^' | head ffffffffc0615000 ^@ rfcomm_session_get [rfcomm] ffffffffc061c060 ^@ session_list [rfcomm] ffffffffc06150d0 ^@ rfcomm_send_frame [rfcomm] ffffffffc0615130 ^@ rfcomm_make_uih [rfcomm] ffffffffc07ed58d ^@ bnep_exit [bnep] ffffffffc07ec000 ^@ bnep_rx_control [bnep] ffffffffc07ec1a0 ^@ bnep_session [bnep] ffffffffc07e7000 ^@ input_leds_event [input_leds] ffffffffc07e9000 ^@ input_leds_handler [input_leds] ffffffffc07e7010 ^@ input_leds_disconnect [input_leds] Notably, the null bytes (represented above by ^@) can confuse tools. Fix by correcting the buffer length. Fixes:91fb02f315("module: Move kallsyms support into a separate file") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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 Restructured Text 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.