From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>, Jiri Olsa <jolsa@redhat.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] perf tools: Fix mode setting in copyfile_mode_ns()
Date: Mon, 7 Oct 2019 10:02:21 +0300 [thread overview]
Message-ID: <20191007070221.11158-1-adrian.hunter@intel.com> (raw)
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>
---
tools/perf/util/copyfile.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/copyfile.c b/tools/perf/util/copyfile.c
index 3fa0db136667..47e03de7c235 100644
--- a/tools/perf/util/copyfile.c
+++ b/tools/perf/util/copyfile.c
@@ -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);
--
2.17.1
next reply other threads:[~2019-10-07 7:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 7:02 Adrian Hunter [this message]
2019-10-07 10:47 ` [PATCH] perf tools: Fix mode setting in copyfile_mode_ns() Jiri Olsa
2019-10-15 15:07 ` Arnaldo Carvalho de Melo
2019-10-21 6:26 ` [tip: perf/urgent] " tip-bot2 for Adrian Hunter
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