On Thu, Feb 02, 2023 at 12:27:04PM +0100, Mateusz Grzonka wrote:
> Also check if autorebuild.pid is a symlink, which we shouldn't accept.
>
> Signed-off-by: Mateusz Grzonka <mateusz.grzonka@xxxxxxxxx>
Acked-by: Coly Li <colyli@xxxxxxx>
> ---
> Monitor.c | 89 ++++++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 62 insertions(+), 27 deletions(-)
>
> diff --git a/Monitor.c b/Monitor.c
> index 14a2dfe5..44918184 100644
> --- a/Monitor.c
> +++ b/Monitor.c
> @@ -32,6 +32,7 @@
> #include <libudev.h>
> #endif
>
> +#define TASK_COMM_LEN 16
> #define EVENT_NAME_MAX 32
> #define AUTOREBUILD_PID_PATH MDMON_DIR "/autorebuild.pid"
>
> @@ -224,7 +225,7 @@ int Monitor(struct mddev_dev *devlist,
> info.hostname[sizeof(info.hostname) - 1] = '\0';
>
> if (share){
> - if (check_one_sharer(c->scan))
> + if (check_one_sharer(c->scan) == 2)
> return 1;
> }
>
> @@ -406,39 +407,73 @@ static int make_daemon(char *pidfile)
> return -1;
> }
>
> +/*
> + * check_one_sharer() - Checks for other mdmon processes running.
> + *
> + * Return:
> + * 0 - no other processes running,
> + * 1 - warning,
> + * 2 - error, or when scan mode is enabled, and one mdmon process already exists
> + */
> static int check_one_sharer(int scan)
> {
> int pid;
> - FILE *comm_fp;
> - FILE *fp;
> + FILE *fp, *comm_fp;
> char comm_path[PATH_MAX];
> - char path[PATH_MAX];
> - char comm[20];
> -
> - sprintf(path, "%s/autorebuild.pid", MDMON_DIR);
> - fp = fopen(path, "r");
> - if (fp) {
> - if (fscanf(fp, "%d", &pid) != 1)
> - pid = -1;
> - snprintf(comm_path, sizeof(comm_path),
> - "/proc/%d/comm", pid);
> - comm_fp = fopen(comm_path, "r");
> - if (comm_fp) {
> - if (fscanf(comm_fp, "%19s", comm) &&
> - strncmp(basename(comm), Name, strlen(Name)) == 0) {
> - if (scan) {
> - pr_err("Only one autorebuild process allowed in scan mode, aborting\n");
> - fclose(comm_fp);
> - fclose(fp);
> - return 1;
> - } else {
> - pr_err("Warning: One autorebuild process already running.\n");
> - }
> - }
> + char comm[TASK_COMM_LEN];
> +
> + if (!is_directory(MDMON_DIR)) {
> + pr_err("%s is not a regular directory.\n", MDMON_DIR);
> + return 2;
> + }
> +
> + if (access(AUTOREBUILD_PID_PATH, F_OK) != 0)
> + return 0;
> +
> + if (!is_file(AUTOREBUILD_PID_PATH)) {
> + pr_err("%s is not a regular file.\n", AUTOREBUILD_PID_PATH);
> + return 2;
> + }
> +
> + fp = fopen(AUTOREBUILD_PID_PATH, "r");
> + if (!fp) {
> + pr_err("Cannot open %s file.\n", AUTOREBUILD_PID_PATH);
> + return 2;
> + }
> +
> + if (fscanf(fp, "%d", &pid) != 1) {
> + pr_err("Cannot read pid from %s file.\n", AUTOREBUILD_PID_PATH);
> + fclose(fp);
> + return 2;
> + }
> +
> + snprintf(comm_path, sizeof(comm_path), "/proc/%d/comm", pid);
> +
> + comm_fp = fopen(comm_path, "r");
> + if (!comm_fp) {
> + dprintf("Warning: Cannot open %s, continuing\n", comm_path);
> + fclose(fp);
> + return 1;
> + }
> +
> + if (fscanf(comm_fp, "%15s", comm) == 0) {
> + dprintf("Warning: Cannot read comm from %s, continuing\n", comm_path);
> + fclose(comm_fp);
> + fclose(fp);
> + return 1;
> + }
> +
> + if (strncmp(basename(comm), Name, strlen(Name)) == 0) {
> + if (scan) {
> + pr_err("Only one autorebuild process allowed in scan mode, aborting\n");
> fclose(comm_fp);
> + fclose(fp);
> + return 2;
> }
> - fclose(fp);
> + pr_err("Warning: One autorebuild process already running.\n");
> }
> + fclose(comm_fp);
> + fclose(fp);
> return 0;
> }
>
> --
> 2.26.2
>
--
Coly Li
