1 files changed, 55 insertions, 10 deletions

diff --git a/src/fcopy/main.c b/src/fcopy/main.c
index 01633be59..572e9f601 100644
--- a/src/fcopy/main.c
+++ b/src/fcopy/main.c
@@ -51,8 +51,9 @@ static int selinux_enabled = -1;
 #endif
 
 // copy from firejail/selinux.c
-static void selinux_relabel_path(const char *path, const char *inside_path)
-{
+static void selinux_relabel_path(const char *path, const char *inside_path) {
+        assert(path);
+        assert(inside_path);
 #if HAVE_SELINUX
         char procfs_path[64];
         char *fcon = NULL;
@@ -172,6 +173,51 @@ static void mkdir_attr(const char *fname, mode_t mode, uid_t uid, gid_t gid) {
         }
 }
 
+static char *proc_pid_to_self(const char *target) {
+        assert(target);
+        char *use_target = 0;
+        char *proc_pid = 0;
+
+        if (!(use_target = realpath(target, NULL)))
+                goto done;
+
+        // target is under /proc/<PID>?
+        static const char proc[] = "/proc/";
+        if (strncmp(use_target, proc, sizeof(proc) - 1))
+                goto done;
+
+        int digit = use_target[sizeof(proc) - 1];
+        if (digit < '1' || digit > '9')
+                goto done;
+
+        // check where /proc/self points to
+        static const char proc_self[] = "/proc/self";
+        if (!(proc_pid = realpath(proc_self, NULL)))
+                goto done;
+
+        // redirect /proc/PID/xxx -> /proc/self/XXX
+        size_t pfix = strlen(proc_pid);
+        if (strncmp(use_target, proc_pid, pfix))
+                goto done;
+
+        if (use_target[pfix] != 0 && use_target[pfix] != '/')
+                goto done;
+
+        char *tmp;
+        if (asprintf(&tmp, "%s%s", proc_self, use_target + pfix) != -1) {
+                if (arg_debug)
+                        fprintf(stderr, "SYMLINK %s\n  -->   %s\n", use_target, tmp);
+                free(use_target);
+                use_target = tmp;
+        }
+        else
+                errExit("asprintf");
+
+done:
+        if (proc_pid)
+                free(proc_pid);
+        return use_target;
+}
 
 void copy_link(const char *target, const char *linkpath, mode_t mode, uid_t uid, gid_t gid) {
         (void) mode;
@@ -183,7 +229,7 @@ void copy_link(const char *target, const char *linkpath, mode_t mode, uid_t uid,
         if (lstat(linkpath, &s) == 0)
                return;
 
-        char *rp = realpath(target, NULL);
+        char *rp = proc_pid_to_self(target);
         if (rp) {
                 if (symlink(rp, linkpath) == -1) {
                         free(rp);
@@ -227,16 +273,14 @@ static int fs_copydir(const char *infname, const struct stat *st, int ftype, str
                         first = 0;
                 else if (!arg_quiet)
                         fprintf(stderr, "Warning fcopy: skipping %s, file already present\n", infname);
-                free(outfname);
-                return 0;
+                goto out;
         }
 
         // extract mode and ownership
         if (stat(infname, &s) != 0) {
                 if (!arg_quiet)
                         fprintf(stderr, "Warning fcopy: skipping %s, cannot find inode\n", infname);
-                free(outfname);
-                return 0;
+                goto out;
         }
         uid_t uid = s.st_uid;
         gid_t gid = s.st_gid;
@@ -246,8 +290,7 @@ static int fs_copydir(const char *infname, const struct stat *st, int ftype, str
         if ((s.st_size + size_cnt) > copy_limit) {
                 fprintf(stderr, "Error fcopy: size limit of %lu MB reached\n", (copy_limit / 1024) / 1024);
                 size_limit_reached = 1;
-                free(outfname);
-                return 0;
+                goto out;
         }
 
         file_cnt++;
@@ -262,7 +305,8 @@ static int fs_copydir(const char *infname, const struct stat *st, int ftype, str
         else if (ftype == FTW_SL) {
                 copy_link(infname, outfname, mode, uid, gid);
         }
-
+out:
+        free(outfname);
         return(0);
 }
 
@@ -295,6 +339,7 @@ static char *check(const char *src) {
                 return rsrc;                      // normal exit from the function
 
 errexit:
+        free(rsrc);
         fprintf(stderr, "Error fcopy: invalid file %s\n", src);
         exit(1);
 }