Messages in this thread | | | Date | Mon, 11 Jul 2022 10:48:16 +0300 | Subject | Re: [PATCH] modules: Fix corruption of /proc/kallsyms | From | Adrian Hunter <> |
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On 2/07/22 00:40, Luis Chamberlain wrote: > On Fri, Jul 01, 2022 at 12:44:03PM +0300, Adrian Hunter wrote: >> The commit 91fb02f31505 ("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: 91fb02f31505 ("module: Move kallsyms support into a separate file") >> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > > Queued up thanks! > > Luis
Thanks for processing this.
I notice it is -rc6 and I do not see it in Linus' tree. This is a fix for a regression, shouldn't it be included in 5.19?
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