Thank you for the fix, Philipp. Applied: https://github.com/crash-utility/crash/commit/01d20ca1861ffaf449c1c60aa0536e9f42200ad3
On Fri, Nov 12, 2021 at 1:03 AM <[email protected]> wrote: > Date: Thu, 11 Nov 2021 07:45:51 +0000 > From: HAGIO KAZUHITO(?????) <[email protected]> > To: Philipp Rudo <[email protected]> > Cc: "Discussion list for crash utility usage, maintenance and > development" <[email protected]> > Subject: Re: [Crash-utility] [PATCH] Fix live debugging with > lockdown=integrity > Message-ID: > < > tyypr01mb67772f7c8616e337ff66787cdd...@tyypr01mb6777.jpnprd01.prod.outlook.com > > > > Content-Type: text/plain; charset="iso-2022-jp" > > -----Original Message----- > > With kernel lockdown the access to kernel interfaces that allow to > > extract confidential information (lockdown=confidentiality) or modify a > > running kernel (lockdown=integrity) can be restricted. Two of the > > interfaces that can be restricted are /dev/mem (integrity & > > confidentiality) and /proc/kcore (confidentiality). With > > lockdown=integrity this leads to a situation where /dev/mem exists but > > is not readable while /proc/kcore exists and is readable. This breaks > > crash's live debugging when it is invoked without argument, i.e. > > > > $ crash > > [...] > > crash: /dev/mem: Operation not permitted > > > > while passing /proc/kcore as image succeeds. The reason for this is that > > crash always picks /dev/mem as source when it exits but doesn't check if > > it is readable. Fix this by only selecting /dev/mem when it is readable. > > > > Signed-off-by: Philipp Rudo <[email protected]> > > Thank you for the patch. > > Acked-by: Kazuhito Hagio <[email protected]> > > Kazu > > > --- > > filesys.c | 2 +- > > main.c | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/filesys.c b/filesys.c > > index 3361b6c..43cbe82 100644 > > --- a/filesys.c > > +++ b/filesys.c > > @@ -3666,7 +3666,7 @@ get_live_memory_source(void) > > if (pc->live_memsrc) > > goto live_report; > > > > - if (file_exists("/dev/mem", NULL)) > > + if (file_readable("/dev/mem")) > > pc->live_memsrc = "/dev/mem"; > > else if (file_exists("/proc/kcore", NULL)) { > > pc->flags &= ~DEVMEM; > > diff --git a/main.c b/main.c > > index 71c59d2..b278c22 100644 > > --- a/main.c > > +++ b/main.c > > @@ -1119,7 +1119,7 @@ setup_environment(int argc, char **argv) > > pc->flags2 |= REDZONE; > > pc->confd = -2; > > pc->machine_type = MACHINE_TYPE; > > - if (file_exists("/dev/mem", NULL)) { /* defaults until argv[] > is parsed */ > > + if (file_readable("/dev/mem")) { /* defaults until argv[] is > parsed */ > > pc->readmem = read_dev_mem; > > pc->writemem = write_dev_mem; > > } else if (file_exists("/proc/kcore", NULL)) { > > -- > > 2.31.1 >
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