Messages in this thread | | | Date | Mon, 11 Jul 2022 09:02:28 -0700 | From | Luis Chamberlain <> | Subject | Re: [PATCH] modules: Fix corruption of /proc/kallsyms |
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On Mon, Jul 11, 2022 at 10:48:16AM +0300, Adrian Hunter wrote: > 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?
Yeah sorry this will get to Linus today.
Luis
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