[lxc-devel] [PATCH] Make mount_entry_create_*_dirs() more robust
Christian Brauner
christianvanbrauner at gmail.com
Wed Oct 7 17:34:02 UTC 2015
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 at gmail.com>
---
src/lxc/conf.c | 91 ++++++++++++++++++++++++++--------------------------------
1 file changed, 41 insertions(+), 50 deletions(-)
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 0e3421b..16a62f8 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1816,20 +1816,22 @@ static void cull_mntent_opt(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 = NULL;
+ char lxcpath[MAXPATHLEN];
char *upperdir = NULL;
char *workdir = NULL;
char **opts = NULL;
+ int ret = 0;
size_t arrlen = 0;
size_t dirlen = 0;
size_t i;
size_t len = 0;
size_t rootfslen = 0;
- if (!rootfs->path)
+ if (!rootfs->path || !lxc_name || !lxc_path)
return -1;
opts = lxc_string_split(mntent->mnt_opts, ',');
@@ -1845,19 +1847,11 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
workdir = opts[i] + len;
}
- lxcpath = strdup(rootfs->path);
- if (!lxcpath) {
- lxc_free_array((void **)opts, free);
- return -1;
- }
-
- del = strstr(lxcpath, "/rootfs");
- if (!del) {
- free(lxcpath);
+ ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
+ if (ret < 0 || ret >= MAXPATHLEN) {
lxc_free_array((void **)opts, free);
return -1;
}
- *del = '\0';
dirlen = strlen(lxcpath);
rootfslen = strlen(rootfs->path);
@@ -1877,25 +1871,26 @@ static int mount_entry_create_overlay_dirs(const struct mntent *mntent,
WARN("Failed to create workdir");
}
- free(lxcpath);
lxc_free_array((void **)opts, free);
return 0;
}
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 = NULL;
+ char lxcpath[MAXPATHLEN];
char *scratch = NULL;
char *tmp = NULL;
char *upperdir = NULL;
char **opts = NULL;
+ int ret = 0;
size_t arrlen = 0;
size_t i;
size_t len = 0;
- if (!rootfs->path)
+ if (!rootfs->path || !lxc_name || !lxc_path)
return -1;
opts = lxc_string_split(mntent->mnt_opts, ',');
@@ -1919,19 +1914,11 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
return -1;
}
- lxcpath = strdup(rootfs->path);
- if (!lxcpath) {
- lxc_free_array((void **)opts, free);
- return -1;
- }
-
- del = strstr(lxcpath, "/rootfs");
- if (!del) {
- free(lxcpath);
+ ret = snprintf(lxcpath, MAXPATHLEN, "%s/%s", lxc_path, lxc_name);
+ if (ret < 0 || ret >= MAXPATHLEN) {
lxc_free_array((void **)opts, free);
return -1;
}
- *del = '\0';
/* We neither allow users to create upperdirs outside the containerdir
* nor inside the rootfs. The latter might be debatable. */
@@ -1940,23 +1927,24 @@ static int mount_entry_create_aufs_dirs(const struct mntent *mntent,
WARN("Failed to create upperdir");
}
- free(lxcpath);
lxc_free_array((void **)opts, free);
return 0;
}
+
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;
int ret = 0;
FILE *pathfile = NULL;
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;
} 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;
}
@@ -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,
- 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;
char *mntdata;
int ret;
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)
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)
{
- 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,
const struct lxc_rootfs *rootfs,
- const char *lxc_name)
+ const char *lxc_name,
+ const char *lxc_path)
{
char *aux;
char path[MAXPATHLEN];
@@ -2062,11 +2052,13 @@ skipabs:
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,
- const struct lxc_rootfs *rootfs)
+ const struct lxc_rootfs *rootfs,
+ const char *lxc_name,
+ const char *lxc_path)
{
char path[MAXPATHLEN];
int ret;
@@ -2078,11 +2070,11 @@ static int mount_entry_on_relative_rootfs(struct mntent *mntent,
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,
- const char *lxc_name)
+ const char *lxc_name, const char *lxc_path)
{
struct mntent mntent;
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 */
if (mntent.mnt_dir[0] != '/') {
- if (mount_entry_on_relative_rootfs(&mntent,
- rootfs))
+ if (mount_entry_on_relative_rootfs(&mntent, rootfs, lxc_name, lxc_path))
goto out;
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;
}
@@ -2116,7 +2107,7 @@ out:
}
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;
int ret;
@@ -2130,7 +2121,7 @@ static int setup_mount(const struct lxc_rootfs *rootfs, const char *fstab,
return -1;
}
- ret = mount_file_entries(rootfs, file, lxc_name);
+ ret = mount_file_entries(rootfs, file, lxc_name, lxc_path);
endmntent(file);
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,
- const char *lxc_name)
+ const char *lxc_name, const char *lxc_path)
{
FILE *file;
int ret;
@@ -2167,7 +2158,7 @@ static int setup_mount_entries(const struct lxc_rootfs *rootfs, struct lxc_list
if (!file)
return -1;
- ret = mount_file_entries(rootfs, file, lxc_name);
+ ret = mount_file_entries(rootfs, file, lxc_name, lxc_path);
fclose(file);
return ret;
@@ -3891,12 +3882,12 @@ int lxc_setup(struct lxc_handler *handler)
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);
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);
return -1;
}
--
2.6.1
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