Commit 5a0baf51 authored Oct 07, 2019 by Adrian Hunter Committed by Arnaldo Carvalho de Melo Oct 15, 2019

perf tools: Fix mode setting in copyfile_mode_ns()



slow_copyfile() opens the file by name, so "write" permissions must not
be removed in copyfile_mode_ns() before calling slow_copyfile().

Example:

 Before:

  $ sudo chmod +r /proc/kcore
  $ sudo setcap "cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_sys_rawio=ep" tools/perf/perf
  $ tools/perf/perf buildid-cache -k /proc/kcore
  Couldn't add /proc/kcore

 After:

  $ sudo chmod +r /proc/kcore
  $ sudo setcap "cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_sys_rawio=ep" tools/perf/perf
  $ tools/perf/perf buildid-cache -v -k /proc/kcore
  kcore added to build-id cache directory /home/ahunter/.debug/[kernel.kcore]/37e340b1b5a7cf4f57ba8de2bc777359588a957f/2019100709562289

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lore.kernel.org/lkml/20191007070221.11158-1-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent f948eb45

tools/perf/util/copyfile.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -101,14 +101,16 @@ static int copyfile_mode_ns(const char from, const char to, mode_t mode,
		if (tofd < 0)
		goto out;

		if (fchmod(tofd, mode))
		goto out_close_to;

		if (st.st_size == 0) { /* /proc? do it slowly... */
		err = slow_copyfile(from, tmp, nsi);
		if (!err && fchmod(tofd, mode))
		err = -1;
		goto out_close_to;
		}

		if (fchmod(tofd, mode))
		goto out_close_to;

		nsinfo__mountns_enter(nsi, &nsc);
		fromfd = open(from, O_RDONLY);
		nsinfo__mountns_exit(&nsc);

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