api: null terminate readlink buffer in cgroup_get_procname_from_procfs()

Fix readlink buffer null termination warning, reported by Coverity tool:

CID 258273 (#2 of 2): String not null terminated (STRING_NULL).
string_null: Passing unterminated string buf to strdup, which expects a
null-terminated string.

As per the man pages (man 2 readlink):
"readlink() does not append a null byte to buf.  It  will (silently)
truncate the contents (to a length of bufsiz characters), in case the
buffer is too small to hold all of the contents."

Explicitly null terminate the buffer passed to readlink() in
cgroup_get_procname_from_procfs()

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
(cherry picked from commit 397554c9df86ec7d06e017b877573859c60c258f)

diff --git a/src/api.c b/src/api.c
index 39bd5f239f8a5a88cc1a4ade1132078ff2379440..2836e3d16d32f95b8f043c068c061105d1b323e8 100644 (file)
--- a/src/api.c
+++ b/src/api.c
@@ -5333,6 +5333,9 @@ int cgroup_get_procname_from_procfs(pid_t pid, char **procname)
                *procname = pname_status;
                return 0;
        }
+       /* readlink doesn't append a null */
+       buf[FILENAME_MAX - 1] = '\0';
+
        if (!strncmp(pname_status, basename(buf), TASK_COMM_LEN - 1)) {
                /*
                 * The taken process name from /proc/<pid>/status is