Skip to content

L
lxc
Commit d6dddf6d by Christian Brauner Committed by Stéphane Graber
Options

Parse rootfs->path

The mount_entry_overlay_dirs() and mount_entry_aufs_dirs() functions create workdirs and upperdirs for overlay and aufs lxc.mount.entry entries. They try to make sure that the workdirs and upperdirs can only be created under the containerdir (e.g. /path/to/the/container/CONTAINERNAME). In order to do this the right hand side of if ((strncmp(upperdir, lxcpath, dirlen) == 0) && (strncmp(upperdir, rootfs->path, rootfslen) != 0)) was thought to check if the rootfs->path is not present in the workdir and upperdir mount options. But the current check is bogus since it will be trivially true whenever the container is a block-dev or overlay or aufs backed since the rootfs->path will then have a form like e.g. overlayfs:/some/path:/some/other/path This patch adds the function ovl_get_rootfs_dir() which parses rootfs->path by searching backwards for the first occurrence of the delimiter pair ":/". We do not simply search for ":" since it might be used in path names. If ":/" is not found we assume the container is directory backed and simply return strdup(rootfs->path). Signed-off-by: 's avatarChristian Brauner <christianvanbrauner@gmail.com> Acked-by: 's avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
parent 6c351aea
Showing with 73 additions and 25 deletions
src/lxc/conf.c
...@@ -1815,12 +1815,48 @@ static void cull_mntent_opt(struct mntent *mntent) ...@@ -1815,12 +1815,48 @@ static void cull_mntent_opt(struct mntent *mntent)
} }
} }
static char *ovl_get_rootfs_dir(const char *rootfs_path, size_t *rootfslen)
{
char *rootfsdir = NULL;
char *s1 = NULL;
char *s2 = NULL;
char *s3 = NULL;
if (!rootfs_path || !rootfslen)
return NULL;
s1 = strdup(rootfs_path);
if (!s1)
return NULL;
if ((s2 = strstr(s1, ":/"))) {
s2 = s2 + 1;
if ((s3 = strstr(s2, ":/")))
*s3 = '\0';
rootfsdir = strdup(s2);
if (!rootfsdir) {
free(s1);
return NULL;
}
}
if (!rootfsdir)
rootfsdir = s1;
else
free(s1);
*rootfslen = strlen(rootfsdir);
return rootfsdir;
}
static int mount_entry_create_overlay_dirs(const struct mntent *mntent, static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
const struct lxc_rootfs *rootfs, const struct lxc_rootfs *rootfs,
const char *lxc_name, const char *lxc_name,
const char *lxc_path) const char *lxc_path)
{ {
char lxcpath[MAXPATHLEN]; char lxcpath[MAXPATHLEN];
char *rootfsdir = NULL;
char *upperdir = NULL; char *upperdir = NULL;
char *workdir = NULL; char *workdir = NULL;
char **opts = NULL; char **opts = NULL;
...@@ -1832,13 +1868,13 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent, ...@@ -1832,13 +1868,13 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
size_t rootfslen = 0; size_t rootfslen = 0;
if (!rootfs->path || !lxc_name || !lxc_path) if (!rootfs->path || !lxc_name || !lxc_path)
return -1; goto err;
opts = lxc_string_split(mntent->mnt_opts, ','); opts = lxc_string_split(mntent->mnt_opts, ',');
if (opts) if (opts)
arrlen = lxc_array_len((void **)opts); arrlen = lxc_array_len((void **)opts);
else else
return -1; goto err;
for (i = 0; i < arrlen; i++) { for (i = 0; i < arrlen; i++) {
if (strstr(opts[i], "upperdir=") && (strlen(opts[i]) > (len = strlen("upperdir=")))) if (strstr(opts[i], "upperdir=") && (strlen(opts[i]) > (len = strlen("upperdir="))))
...@@ -1848,31 +1884,37 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent, ...@@ -1848,31 +1884,37 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
} }
ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name); ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
if (ret < 0 || ret >= MAXPATHLEN) { if (ret < 0 || ret >= MAXPATHLEN)
lxc_free_array((void **)opts, free); goto err;
return -1;
} rootfsdir = ovl_get_rootfs_dir(rootfs->path, &rootfslen);
if (!rootfsdir)
goto err;
dirlen = strlen(lxcpath); dirlen = strlen(lxcpath);
rootfslen = strlen(rootfs->path);
/* We neither allow users to create upperdirs and workdirs outside the /* We neither allow users to create upperdirs and workdirs outside the
* containerdir nor inside the rootfs. The latter might be debatable. */ * containerdir nor inside the rootfs. The latter might be debatable. */
if (upperdir) if (upperdir)
if ((strncmp(upperdir, lxcpath, dirlen) == 0) && (strncmp(upperdir, rootfs->path, rootfslen) != 0)) if ((strncmp(upperdir, lxcpath, dirlen) == 0) && (strncmp(upperdir, rootfsdir, rootfslen) != 0))
if (mkdir_p(upperdir, 0755) < 0) { if (mkdir_p(upperdir, 0755) < 0) {
WARN("Failed to create upperdir"); WARN("Failed to create upperdir");
} }
if (workdir) if (workdir)
if ((strncmp(workdir, lxcpath, dirlen) == 0) && (strncmp(workdir, rootfs->path, rootfslen) != 0)) if ((strncmp(workdir, lxcpath, dirlen) == 0) && (strncmp(workdir, rootfsdir, rootfslen) != 0))
if (mkdir_p(workdir, 0755) < 0) { if (mkdir_p(workdir, 0755) < 0) {
WARN("Failed to create workdir"); WARN("Failed to create workdir");
} }
free(rootfsdir);
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return 0; return 0;
err:
free(rootfsdir);
lxc_free_array((void **)opts, free);
return -1;
} }
static int mount_entry_create_aufs_dirs(const struct mntent *mntent, static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
...@@ -1881,6 +1923,7 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent, ...@@ -1881,6 +1923,7 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
const char *lxc_path) const char *lxc_path)
{ {
char lxcpath[MAXPATHLEN]; char lxcpath[MAXPATHLEN];
char *rootfsdir = NULL;
char *scratch = NULL; char *scratch = NULL;
char *tmp = NULL; char *tmp = NULL;
char *upperdir = NULL; char *upperdir = NULL;
...@@ -1889,46 +1932,51 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent, ...@@ -1889,46 +1932,51 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
size_t arrlen = 0; size_t arrlen = 0;
size_t i; size_t i;
size_t len = 0; size_t len = 0;
size_t rootfslen = 0;
if (!rootfs->path || !lxc_name || !lxc_path) if (!rootfs->path || !lxc_name || !lxc_path)
return -1; goto err;
opts = lxc_string_split(mntent->mnt_opts, ','); opts = lxc_string_split(mntent->mnt_opts, ',');
if (opts) if (opts)
arrlen = lxc_array_len((void **)opts); arrlen = lxc_array_len((void **)opts);
else else
return -1; goto err;
for (i = 0; i < arrlen; i++) { for (i = 0; i < arrlen; i++) {
if (strstr(opts[i], "br=") && (strlen(opts[i]) > (len = strlen("br=")))) if (strstr(opts[i], "br=") && (strlen(opts[i]) > (len = strlen("br="))))
tmp = opts[i] + len; tmp = opts[i] + len;
} }
if (!tmp) { if (!tmp)
lxc_free_array((void **)opts, free); goto err;
return -1;
}
upperdir = strtok_r(tmp, ":=", &scratch); upperdir = strtok_r(tmp, ":=", &scratch);
if (!upperdir) { if (!upperdir)
lxc_free_array((void **)opts, free); goto err;
return -1;
}
ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name); ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
if (ret < 0 || ret >= MAXPATHLEN) { if (ret < 0 || ret >= MAXPATHLEN)
lxc_free_array((void **)opts, free); goto err;
return -1;
} rootfsdir = ovl_get_rootfs_dir(rootfs->path, &rootfslen);
if (!rootfsdir)
goto err;
/* We neither allow users to create upperdirs outside the containerdir /* We neither allow users to create upperdirs outside the containerdir
* nor inside the rootfs. The latter might be debatable. */ * nor inside the rootfs. The latter might be debatable. */
if ((strncmp(upperdir, lxcpath, strlen(lxcpath)) == 0) && (strncmp(upperdir, rootfs->path, strlen(rootfs->path)) != 0)) if ((strncmp(upperdir, lxcpath, strlen(lxcpath)) == 0) && (strncmp(upperdir, rootfsdir, rootfslen) != 0))
if (mkdir_p(upperdir, 0755) < 0) { if (mkdir_p(upperdir, 0755) < 0) {
WARN("Failed to create upperdir"); WARN("Failed to create upperdir");
} }
free(rootfsdir);
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return 0; return 0;
err:
free(rootfsdir);
lxc_free_array((void **)opts, free);
return -1;
} }
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment