diff options
| -rw-r--r-- | src/linux-user-chroot.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/linux-user-chroot.c b/src/linux-user-chroot.c index 6cac578..8b8700d 100644 --- a/src/linux-user-chroot.c +++ b/src/linux-user-chroot.c @@ -54,6 +54,16 @@ #define PR_SET_NO_NEW_PRIVS 38 #endif +/* Totally arbitrary; we're just trying to mitigate somewhat against + * DoS attacks. In practice uids can typically spawn multiple + * processes, so this isn't effective. What is needed is for the + * kernel to understand we're creating bind mounts on behalf of a + * given uid. Most likely this will happen if the kernel obsoletes + * this tool by allowing processes with PR_SET_NO_NEW_PRIVS to create + * private mounts or chroot. + */ +#define MAX_BIND_MOUNTS 1024 + static void fatal (const char *message, ...) __attribute__ ((noreturn)) __attribute__ ((format (printf, 1, 2))); static void fatal_errno (const char *message) __attribute__ ((noreturn)); @@ -145,7 +155,7 @@ main (int argc, gid_t rgid, egid, sgid; int after_mount_arg_index; unsigned int n_mounts = 0; - const unsigned int max_mounts = 50; /* Totally arbitrary... */ + const unsigned int max_mounts = MAX_BIND_MOUNTS; char **program_argv; MountSpec *bind_mounts = NULL; MountSpec *bind_mount_iter; |