src/api.c: fix TOCTOU in cg_get_procname_from_proc_cmdline()

Fix a TOCTOU issue, reported by Coverity tool:

CID 258283 (#1 of 1): Time of check time of use (TOCTOU)1.
fs_check_call: Calling function readlink to perform check on path

Coverity gets confused when a char array is re-used for constructing
different paths and complains about TOCTOU for unrelated paths, fix it
by using different char arrays for different path, as a side effect it
also improves the readability of the code.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>

diff --git a/src/api.c b/src/api.c
index 979a7d56d95aff68ac1b90debddcda0aedd45dc7..72d44b9e0a0ee20e44b354dd4ee44ef34e47946e 100644 (file)
--- a/src/api.c
+++ b/src/api.c
@@ -5720,25 +5720,26 @@ static int cg_get_procname_from_proc_status(pid_t pid, char **procname_status)
 static int cg_get_procname_from_proc_cmdline(pid_t pid, const char *pname_status,
                                             char **pname_cmdline)
 {
+       char pid_cwd_path[FILENAME_MAX];
+       char pid_cmd_path[FILENAME_MAX];
        char buf_pname[FILENAME_MAX];
        char buf_cwd[FILENAME_MAX];
-       char path[FILENAME_MAX];
        int ret = ECGFAIL;
        int len = 0;
        int c = 0;
        FILE *f;
 
        memset(buf_cwd, '\0', sizeof(buf_cwd));
-       sprintf(path, "/proc/%d/cwd", pid);
+       sprintf(pid_cwd_path, "/proc/%d/cwd", pid);
 
-       if (readlink(path, buf_cwd, sizeof(buf_cwd)) < 0)
+       if (readlink(pid_cwd_path, buf_cwd, sizeof(buf_cwd)) < 0)
                return ECGROUPNOTEXIST;
 
        /* readlink doesn't append a null */
        buf_cwd[FILENAME_MAX - 1] = '\0';
 
-       sprintf(path, "/proc/%d/cmdline", pid);
-       f = fopen(path, "re");
+       sprintf(pid_cmd_path, "/proc/%d/cmdline", pid);
+       f = fopen(pid_cmd_path, "re");
        if (!f)
                return ECGROUPNOTEXIST;
 
@@ -5778,13 +5779,13 @@ static int cg_get_procname_from_proc_cmdline(pid_t pid, const char *pname_status
 
                strcat(buf_cwd, "/");
                strcat(buf_cwd, buf_pname);
-               if (!realpath(buf_cwd, path)) {
+               if (!realpath(buf_cwd, pid_cmd_path)) {
                        last_errno = errno;
                        ret = ECGOTHER;
                        break;
                }
 
-               *pname_cmdline = strdup(path);
+               *pname_cmdline = strdup(pid_cmd_path);
                if (*pname_cmdline == NULL) {
                        last_errno = errno;
                        ret = ECGOTHER;