On Mon, Oct 19, 2015 at 02:50:11PM +0000, Serge Hallyn wrote: > Quoting Christian Brauner (christianvanbrau...@gmail.com): > > 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 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. > > > > Signed-off-by: Christian Brauner <christianvanbrau...@gmail.com> > > --- > > src/lxc/conf.c | 126 > > ++++++++++++++++++++++++++++++++++++++++++++++----------- > > 1 file changed, 103 insertions(+), 23 deletions(-) > > > > diff --git a/src/lxc/conf.c b/src/lxc/conf.c > > index 16a62f8..a730a67 100644 > > --- a/src/lxc/conf.c > > +++ b/src/lxc/conf.c > > @@ -1821,6 +1821,11 @@ static int mount_entry_create_overlay_dirs(const > > struct mntent *mntent, > > const char *lxc_path) > > { > > char lxcpath[MAXPATHLEN]; > > + char *end = NULL; > > + char *rootfsdir = NULL; > > + char *s = NULL; > > + char *s1 = NULL; > > + char *tmp = NULL; > > char *upperdir = NULL; > > char *workdir = NULL; > > char **opts = NULL; > > @@ -1830,15 +1835,16 @@ static int mount_entry_create_overlay_dirs(const > > struct mntent *mntent, > > size_t i; > > size_t len = 0; > > size_t rootfslen = 0; > > + size_t slen = 0; > > > > if (!rootfs->path || !lxc_name || !lxc_path) > > - return -1; > > + goto err; > > > > opts = lxc_string_split(mntent->mnt_opts, ','); > > if (opts) > > arrlen = lxc_array_len((void **)opts); > > else > > - return -1; > > + goto err; > > > > for (i = 0; i < arrlen; i++) { > > if (strstr(opts[i], "upperdir=") && (strlen(opts[i]) > (len = > > strlen("upperdir=")))) > > @@ -1848,31 +1854,66 @@ static int mount_entry_create_overlay_dirs(const > > struct mntent *mntent, > > } > > > > ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name); > > - if (ret < 0 || ret >= MAXPATHLEN) { > > - lxc_free_array((void **)opts, free); > > - return -1; > > - } > > + if (ret < 0 || ret >= MAXPATHLEN) > > + goto err; > > > > dirlen = strlen(lxcpath); > > - rootfslen = strlen(rootfs->path); > > + > > Could you put this stuff into a helper, i.e. Can do. Do you mean putting it as a static helper function in conf.c, or in utils.c?
> > rootfsdir = ovl_get_rootfs_dir(rootfs->path, &rootfslen); > > + s = strdup(rootfs->path); > > + if (!s) > > + goto err; > > + > > + s1 = malloc(strlen(rootfs->path) + 1); > > + if (!s1) > > + goto err; > > + end = stpcpy(s1, rootfs->path); > > + > > + /* If we find :/ in rootfs->path it means we either have a block-dev or > > + * overlay or aufs container. */ > > + while ((tmp = strrchr(s, ':'))) { > > + len = strlen(tmp); > > + rootfslen += len; > > + if (strncmp(tmp, ":/", 2) == 0) { > > + rootfsdir = end - rootfslen + 1; > > + rootfslen = strlen(rootfsdir); > > + break; > > + } else { > > + slen = strlen(s); > > + s[slen - len] = '\0'; > > + } > > + } > > + > > + /* If rootfsdir is empty at this point we have a simple directory > > + * container. */ > > + if (!rootfsdir) { > > + rootfsdir = rootfs->path; > > + rootfslen = strlen(rootfs->path); > > + } > > > > /* We neither allow users to create upperdirs and workdirs outside the > > * containerdir nor inside the rootfs. The latter might be debatable. */ > > 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) { > > WARN("Failed to create upperdir"); > > } > > > > > > 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) { > > WARN("Failed to create workdir"); > > } > > > > + free(s); > > + free(s1); > > lxc_free_array((void **)opts, free); > > return 0; > > +err: > > + free(s); > > + free(s1); > > + lxc_free_array((void **)opts, free); > > + return -1; > > } > > > > static int mount_entry_create_aufs_dirs(const struct mntent *mntent, > > @@ -1881,6 +1922,10 @@ static int mount_entry_create_aufs_dirs(const struct > > mntent *mntent, > > const char *lxc_path) > > { > > char lxcpath[MAXPATHLEN]; > > + char *end = NULL; > > + char *rootfsdir = NULL; > > + char *s = NULL; > > + char *s1 = NULL; > > char *scratch = NULL; > > char *tmp = NULL; > > char *upperdir = NULL; > > @@ -1889,44 +1934,79 @@ static int mount_entry_create_aufs_dirs(const > > struct mntent *mntent, > > size_t arrlen = 0; > > size_t i; > > size_t len = 0; > > + size_t rootfslen = 0; > > + size_t slen = 0; > > > > if (!rootfs->path || !lxc_name || !lxc_path) > > - return -1; > > + goto err; > > > > opts = lxc_string_split(mntent->mnt_opts, ','); > > if (opts) > > arrlen = lxc_array_len((void **)opts); > > else > > - return -1; > > + goto err; > > > > for (i = 0; i < arrlen; i++) { > > if (strstr(opts[i], "br=") && (strlen(opts[i]) > (len = > > strlen("br=")))) > > tmp = opts[i] + len; > > } > > - if (!tmp) { > > - lxc_free_array((void **)opts, free); > > - return -1; > > - } > > + if (!tmp) > > + goto err; > > > > upperdir = strtok_r(tmp, ":=", &scratch); > > - if (!upperdir) { > > - lxc_free_array((void **)opts, free); > > - return -1; > > - } > > + if (!upperdir) > > + goto err; > > > > ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name); > > - if (ret < 0 || ret >= MAXPATHLEN) { > > - lxc_free_array((void **)opts, free); > > - return -1; > > + if (ret < 0 || ret >= MAXPATHLEN) > > + goto err; > > + > > + s = strdup(rootfs->path); > > + if (!s) > > + goto err; > > + > > + s1 = malloc(strlen(rootfs->path) + 1); > > + if (!s1) > > + goto err; > > + end = stpcpy(s1, rootfs->path); > > + > > + /* If we find :/ in rootfs->path it means we either have a block-dev or > > + * overlay or aufs container. */ > > + while ((tmp = strrchr(s, ':'))) { > > + len = strlen(tmp); > > + rootfslen += len; > > + if (strncmp(tmp, ":/", 2) == 0) { > > + rootfsdir = end - rootfslen + 1; > > + rootfslen = strlen(rootfsdir); > > + break; > > + } else { > > + slen = strlen(s); > > + s[slen - len] = '\0'; > > + } > > + } > > + > > + /* If rootfsdir is empty at this point we have a simple directory > > + * container. */ > > + if (!rootfsdir) { > > + rootfsdir = rootfs->path; > > + rootfslen = strlen(rootfs->path); > > } > > > > /* We neither allow users to create upperdirs outside the containerdir > > * 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) { > > WARN("Failed to create upperdir"); > > } > > > > + free(s); > > + free(s1); > > + lxc_free_array((void **)opts, free); > > + return 0; > > + > > +err: > > + free(s); > > + free(s1); > > lxc_free_array((void **)opts, free); > > return 0; > > } > > -- > > 2.6.1 > >
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