From 2d9fdb37fea53ba04eaa4ef99b731004ca37c2f4 Mon Sep 17 00:00:00 2001
From: Jianhui Zhao <zhaojh329@gmail.com>
Date: Sat, 30 Jan 2021 15:02:22 +0800
Subject: [PATCH] file: Change the owner to the operator

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>
---
 src/file.c  | 18 +++++++++++++++++
 src/file.h  |  2 ++
 src/utils.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/utils.h |  4 ++++
 4 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/src/file.c b/src/file.c
index e4462aa..0fc8e5f 100644
--- a/src/file.c
+++ b/src/file.c
@@ -181,6 +181,8 @@ bool detect_file_operation(uint8_t *buf, int len, int sid, struct file_context *
     char fifo_name[128];
     pid_t pid;
     int ctlfd;
+    uid_t uid;
+    gid_t gid;
 
     if (len != 12)
         return false;
@@ -190,6 +192,16 @@ bool detect_file_operation(uint8_t *buf, int len, int sid, struct file_context *
 
     memcpy(&pid, buf + 4, 4);
 
+    if (!getuid_pid(pid, &uid)) {
+        kill(pid, SIGTERM);
+        return true;
+    }
+
+    if (!getgid_pid(pid, &gid)) {
+        kill(pid, SIGTERM);
+        return true;
+    }
+
     sprintf(fifo_name, "/tmp/rtty-file-%d.fifo", pid);
 
     ctlfd = open(fifo_name, O_WRONLY);
@@ -218,6 +230,9 @@ bool detect_file_operation(uint8_t *buf, int len, int sid, struct file_context *
         memset(savepath, 0, sizeof(savepath));
         getcwd_pid(pid, savepath, sizeof(savepath) - 1);
         strcat(savepath, "/");
+
+        ctx->uid = uid;
+        ctx->gid = gid;
     } else {
         char path[PATH_MAX] = "";
         char link[128];
@@ -284,6 +299,9 @@ static void start_download_file(struct file_context *ctx, struct buffer *info, i
 
     log_info("download file: %s, size: %u\n", savepath, ctx->total_size);
 
+    if (fchown(fd, ctx->uid, ctx->gid) < 0)
+        log_err("fchown %s fail: %s\n", strerror(errno));
+
     if (ctx->total_size == 0)
         close(fd);
     else
diff --git a/src/file.h b/src/file.h
index ecf8548..3be2e7d 100644
--- a/src/file.h
+++ b/src/file.h
@@ -51,6 +51,8 @@ struct file_context {
     int fd;
     bool busy;
     int ctlfd;
+    uid_t uid;
+    gid_t gid;
     uint32_t total_size;
     uint32_t remain_size;
     struct ev_io iof;  /* used for upload file */
diff --git a/src/utils.c b/src/utils.c
index e8c90b6..3b5f3cd 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -167,4 +167,58 @@ ssize_t getcwd_pid(pid_t pid, char *buf, size_t bufsiz)
     sprintf(link, "/proc/%d/cwd", pid);
 
     return readlink(link, buf, bufsiz);
-}
\ No newline at end of file
+}
+
+bool getuid_pid(pid_t pid, uid_t *uid)
+{
+    char status[128];
+    char line[128];
+    int i = 9;
+    FILE *fp;
+
+    sprintf(status, "/proc/%d/status", pid);
+
+    fp = fopen(status, "r");
+    if (!fp)
+        return false;
+
+    while (i-- > 0) {
+        if (!fgets(line, sizeof(line), fp)) {
+            fclose(fp);
+            return false;
+        }
+    }
+
+    fclose(fp);
+    
+    sscanf(line, "Uid:\t%u", uid);
+    
+    return true;
+}
+
+bool getgid_pid(pid_t pid, gid_t *gid)
+{
+    char status[128];
+    char line[128];
+    int i = 10;
+    FILE *fp;
+
+    sprintf(status, "/proc/%d/status", pid);
+
+    fp = fopen(status, "r");
+    if (!fp)
+        return false;
+
+    while (i-- > 0) {
+        if (!fgets(line, sizeof(line), fp)) {
+            fclose(fp);
+            return false;
+        }
+    }
+
+    fclose(fp);
+    
+    sscanf(line, "Gid:\t%u", gid);
+    
+    return true;
+}
diff --git a/src/utils.h b/src/utils.h
index c7c14db..822ef7e 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -40,4 +40,8 @@ struct mntent *find_mount_point(const char *name);
 
 ssize_t getcwd_pid(pid_t pid, char *buf, size_t bufsiz);
 
+bool getuid_pid(pid_t pid, uid_t *uid);
+
+bool getgid_pid(pid_t pid, gid_t *gid);
+
 #endif