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Make mount_entry_create_*_dirs() more robust

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The mount_entry_create_*_dirs() functions currently assume that the rootfs of
the container is actually named "rootfs". This has the consequence that

	del = strstr(lxcpath, "/rootfs");
	if (!del) {
		free(lxcpath);
		lxc_free_array((void **)opts, free);
		return -1;
	}
	*del = '\0';

will return NULL when the rootfs of a container is not actually named "rootfs".
This means the we return -1 and do not create the necessary upperdir/workdir
directories required for the overlay/aufs mount to work. Hence, let's not make
that assumption. We now pass lxc_path and lxc_name to
mount_entry_create_*_dirs() and create the path directly. To prevent failure we
also have mount_entry_create_*_dirs() check that lxc_name and lxc_path are not
empty when they are passed in.

Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
This commit is contained in:
Christian Brauner 2015-10-07 19:34:02 +02:00 committed by Stéphane Graber
parent d0b2a43477
commit 0a2dddd479
1 changed files with 41 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
src/lxc/conf.c
View File

@ -1816,20 +1816,22 @@ static void cull_mntent_opt(struct mntent *mntent)
} }
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_path)
{ {
char *del = NULL; char lxcpath[MAXPATHLEN];
char *lxcpath = NULL;
char *upperdir = NULL; char *upperdir = NULL;
char *workdir = NULL; char *workdir = NULL;
char **opts = NULL; char **opts = NULL;
int ret = 0;
size_t arrlen = 0; size_t arrlen = 0;
size_t dirlen = 0; size_t dirlen = 0;
size_t i; size_t i;
size_t len = 0; size_t len = 0;
size_t rootfslen = 0; size_t rootfslen = 0;
if (!rootfs->path) if (!rootfs->path || !lxc_name || !lxc_path)
return -1; return -1;
opts = lxc_string_split(mntent->mnt_opts, ','); opts = lxc_string_split(mntent->mnt_opts, ',');
@ -1845,20 +1847,12 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
workdir = opts[i] + len; workdir = opts[i] + len;
} }
lxcpath = strdup(rootfs->path); ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
if (!lxcpath) { if (ret < 0 || ret >= MAXPATHLEN) {
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return -1; return -1;
} }
del = strstr(lxcpath, "/rootfs");
if (!del) {
free(lxcpath);
lxc_free_array((void **)opts, free);
return -1;
}
*del = '\0';
dirlen = strlen(lxcpath); dirlen = strlen(lxcpath);
rootfslen = strlen(rootfs->path); rootfslen = strlen(rootfs->path);
@ -1877,25 +1871,26 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
WARN("Failed to create workdir"); WARN("Failed to create workdir");
} }
free(lxcpath);
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return 0; return 0;
} }
static int mount_entry_create_aufs_dirs(const struct mntent *mntent, static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
const struct lxc_rootfs *rootfs) const struct lxc_rootfs *rootfs,
const char *lxc_name,
const char *lxc_path)
{ {
char *del = NULL; char lxcpath[MAXPATHLEN];
char *lxcpath = NULL;
char *scratch = NULL; char *scratch = NULL;
char *tmp = NULL; char *tmp = NULL;
char *upperdir = NULL; char *upperdir = NULL;
char **opts = NULL; char **opts = NULL;
int ret = 0;
size_t arrlen = 0; size_t arrlen = 0;
size_t i; size_t i;
size_t len = 0; size_t len = 0;
if (!rootfs->path) if (!rootfs->path || !lxc_name || !lxc_path)
return -1; return -1;
opts = lxc_string_split(mntent->mnt_opts, ','); opts = lxc_string_split(mntent->mnt_opts, ',');
@ -1919,20 +1914,12 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
return -1; return -1;
} }
lxcpath = strdup(rootfs->path); ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
if (!lxcpath) { if (ret < 0 || ret >= MAXPATHLEN) {
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return -1; return -1;
} }
del = strstr(lxcpath, "/rootfs");
if (!del) {
free(lxcpath);
lxc_free_array((void **)opts, free);
return -1;
}
*del = '\0';
/* 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, rootfs->path, strlen(rootfs->path)) != 0))
@ -1940,23 +1927,24 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
WARN("Failed to create upperdir"); WARN("Failed to create upperdir");
} }
free(lxcpath);
lxc_free_array((void **)opts, free); lxc_free_array((void **)opts, free);
return 0; return 0;
} }
static int mount_entry_create_dir_file(const struct mntent *mntent, static int mount_entry_create_dir_file(const struct mntent *mntent,
const char* path, const struct lxc_rootfs *rootfs) const char* path, const struct lxc_rootfs *rootfs,
const char *lxc_name, const char *lxc_path)
{ {
char *pathdirname = NULL; char *pathdirname = NULL;
int ret = 0; int ret = 0;
FILE *pathfile = NULL; FILE *pathfile = NULL;
if (strncmp(mntent->mnt_type, "overlay", 7) == 0) { if (strncmp(mntent->mnt_type, "overlay", 7) == 0) {
if (mount_entry_create_overlay_dirs(mntent, rootfs) < 0) if (mount_entry_create_overlay_dirs(mntent, rootfs, lxc_name, lxc_path) < 0)
return -1; return -1;
} else if (strncmp(mntent->mnt_type, "aufs", 4) == 0) { } else if (strncmp(mntent->mnt_type, "aufs", 4) == 0) {
if (mount_entry_create_aufs_dirs(mntent, rootfs) < 0) if (mount_entry_create_aufs_dirs(mntent, rootfs, lxc_name, lxc_path) < 0)
return -1; return -1;
} }
@ -1986,14 +1974,15 @@ static int mount_entry_create_dir_file(const struct mntent *mntent,
} }
static inline int mount_entry_on_generic(struct mntent *mntent, static inline int mount_entry_on_generic(struct mntent *mntent,
const char* path, const struct lxc_rootfs *rootfs) const char* path, const struct lxc_rootfs *rootfs,
const char *lxc_name, const char *lxc_path)
{ {
unsigned long mntflags; unsigned long mntflags;
char *mntdata; char *mntdata;
int ret; int ret;
bool optional = hasmntopt(mntent, "optional") != NULL; bool optional = hasmntopt(mntent, "optional") != NULL;
ret = mount_entry_create_dir_file(mntent, path, rootfs); ret = mount_entry_create_dir_file(mntent, path, rootfs, lxc_name, lxc_path);
if (ret < 0) if (ret < 0)
return optional ? 0 : -1; return optional ? 0 : -1;
@ -2015,12 +2004,13 @@ static inline int mount_entry_on_generic(struct mntent *mntent,
static inline int mount_entry_on_systemfs(struct mntent *mntent) static inline int mount_entry_on_systemfs(struct mntent *mntent)
{ {
return mount_entry_on_generic(mntent, mntent->mnt_dir, NULL); return mount_entry_on_generic(mntent, mntent->mnt_dir, NULL, NULL, NULL);
} }
static int mount_entry_on_absolute_rootfs(struct mntent *mntent, static int mount_entry_on_absolute_rootfs(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)
{ {
char *aux; char *aux;
char path[MAXPATHLEN]; char path[MAXPATHLEN];
@ -2062,11 +2052,13 @@ skipabs:
return -1; return -1;
} }
return mount_entry_on_generic(mntent, path, rootfs); return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
} }
static int mount_entry_on_relative_rootfs(struct mntent *mntent, static int mount_entry_on_relative_rootfs(struct mntent *mntent,
const struct lxc_rootfs *rootfs) const struct lxc_rootfs *rootfs,
const char *lxc_name,
const char *lxc_path)
{ {
char path[MAXPATHLEN]; char path[MAXPATHLEN];
int ret; int ret;
@ -2078,11 +2070,11 @@ static int mount_entry_on_relative_rootfs(struct mntent *mntent,
return -1; return -1;
} }
return mount_entry_on_generic(mntent, path, rootfs); return mount_entry_on_generic(mntent, path, rootfs, lxc_name, lxc_path);
} }
static int mount_file_entries(const struct lxc_rootfs *rootfs, FILE *file, static int mount_file_entries(const struct lxc_rootfs *rootfs, FILE *file,
const char *lxc_name) const char *lxc_name, const char *lxc_path)
{ {
struct mntent mntent; struct mntent mntent;
char buf[4096]; char buf[4096];
@ -2098,13 +2090,12 @@ static int mount_file_entries(const struct lxc_rootfs *rootfs, FILE *file,
/* We have a separate root, mounts are relative to it */ /* We have a separate root, mounts are relative to it */
if (mntent.mnt_dir[0] != '/') { if (mntent.mnt_dir[0] != '/') {
if (mount_entry_on_relative_rootfs(&mntent, if (mount_entry_on_relative_rootfs(&mntent, rootfs, lxc_name, lxc_path))
rootfs))
goto out; goto out;
continue; continue;
} }
if (mount_entry_on_absolute_rootfs(&mntent, rootfs, lxc_name)) if (mount_entry_on_absolute_rootfs(&mntent, rootfs, lxc_name, lxc_path))
goto out; goto out;
} }
@ -2116,7 +2107,7 @@ out:
} }
static int setup_mount(const struct lxc_rootfs *rootfs, const char *fstab, static int setup_mount(const struct lxc_rootfs *rootfs, const char *fstab,
const char *lxc_name) const char *lxc_name, const char *lxc_path)
{ {
FILE *file; FILE *file;
int ret; int ret;
@ -2130,7 +2121,7 @@ static int setup_mount(const struct lxc_rootfs *rootfs, const char *fstab,
return -1; return -1;
} }
ret = mount_file_entries(rootfs, file, lxc_name); ret = mount_file_entries(rootfs, file, lxc_name, lxc_path);
endmntent(file); endmntent(file);
return ret; return ret;
@ -2158,7 +2149,7 @@ FILE *write_mount_file(struct lxc_list *mount)
} }
static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list *mount, static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list *mount,
const char *lxc_name) const char *lxc_name, const char *lxc_path)
{ {
FILE *file; FILE *file;
int ret; int ret;
@ -2167,7 +2158,7 @@ static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list
if (!file) if (!file)
return -1; return -1;
ret = mount_file_entries(rootfs, file, lxc_name); ret = mount_file_entries(rootfs, file, lxc_name, lxc_path);
fclose(file); fclose(file);
return ret; return ret;
@ -3891,12 +3882,12 @@ int lxc_setup(struct lxc_handler *handler)
return -1; return -1;
} }
if (setup_mount(&lxc_conf->rootfs, lxc_conf->fstab, name)) { if (setup_mount(&lxc_conf->rootfs, lxc_conf->fstab, name, lxcpath)) {
ERROR("failed to setup the mounts for '%s'", name); ERROR("failed to setup the mounts for '%s'", name);
return -1; return -1;
} }
if (!lxc_list_empty(&lxc_conf->mount_list) && setup_mount_entries(&lxc_conf->rootfs, &lxc_conf->mount_list, name)) { if (!lxc_list_empty(&lxc_conf->mount_list) && setup_mount_entries(&lxc_conf->rootfs, &lxc_conf->mount_list, name, lxcpath)) {
ERROR("failed to setup the mount entries for '%s'", name); ERROR("failed to setup the mount entries for '%s'", name);
return -1; return -1;
} }