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Subject[tip:perf/urgent] perf symbols: Check kptr_restrict for root
Commit-ID:  38272dc4f1b17437871b786d567e1242d0904f5a
Gitweb: http://git.kernel.org/tip/38272dc4f1b17437871b786d567e1242d0904f5a
Author: Wang Nan <wangnan0@huawei.com>
AuthorDate: Tue, 24 May 2016 09:21:27 +0000
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 27 May 2016 09:41:23 -0300

perf symbols: Check kptr_restrict for root

If kptr_restrict is set to 2, even root is not allowed to see pointers.
This patch checks kptr_restrict even if euid == 0. For root, report
error if kptr_restrict is 2.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464081688-167940-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 20f9cb3..54c4ff2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1933,17 +1933,17 @@ int setup_intlist(struct intlist **list, const char *list_str,
static bool symbol__read_kptr_restrict(void)
{
bool value = false;
+ FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");

- if (geteuid() != 0) {
- FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");
- if (fp != NULL) {
- char line[8];
+ if (fp != NULL) {
+ char line[8];

- if (fgets(line, sizeof(line), fp) != NULL)
- value = atoi(line) != 0;
+ if (fgets(line, sizeof(line), fp) != NULL)
+ value = (geteuid() != 0) ?
+ (atoi(line) != 0) :
+ (atoi(line) == 2);

- fclose(fp);
- }
+ fclose(fp);
}

return value;
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