From: Ian Kent <[email protected]> Add function call_usermodehelper_ns() to allow passing a namespace token to lookup previously stored namespace information for usermode helper execution.
Signed-off-by: Ian Kent <[email protected]> Cc: Benjamin Coddington <[email protected]> Cc: Al Viro <[email protected]> Cc: J. Bruce Fields <[email protected]> Cc: David Howells <[email protected]> Cc: Trond Myklebust <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Eric W. Biederman <[email protected]> Cc: Jeff Layton <[email protected]> --- include/linux/kmod.h | 24 +++++++++++++ kernel/kmod.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 120 insertions(+) diff --git a/include/linux/kmod.h b/include/linux/kmod.h index 77f41ce..a761650 100644 --- a/include/linux/kmod.h +++ b/include/linux/kmod.h @@ -87,9 +87,33 @@ static inline long umh_ns_get_token(long token) static inline void umh_ns_put_token(long token) { } + +static inline int +call_usermodehelper_ns(char *path, char **argv, char **envp, + unsigned int flags, long token) +{ + return -ENOTSUP; +} + +static inline struct subprocess_info * +call_usermodehelper_setup_ns(char *path, char **argv, char **envp, gfp_t gfp_mask, + int (*init)(struct subprocess_info *info, struct cred *new), + void (*cleanup)(struct subprocess_info *), void *data, + long token) +{ + return -ENOTSUP; +} #else extern long umh_ns_get_token(long token); extern void umh_ns_put_token(long token); +extern int +call_usermodehelper_ns(char *path, char **argv, char **envp, + unsigned int flags, long token); +extern struct subprocess_info * +call_usermodehelper_setup_ns(char *path, char **argv, char **envp, gfp_t gfp_mask, + int (*init)(struct subprocess_info *info, struct cred *new), + void (*cleanup)(struct subprocess_info *), void *data, + long token); #endif extern int diff --git a/kernel/kmod.c b/kernel/kmod.c index ddd41f1..d711240 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -842,6 +842,62 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, } EXPORT_SYMBOL(call_usermodehelper_setup); +#ifdef CONFIG_NAMESPACES +/** + * call_usermodehelper_setup_ns - prepare to call a usermode helper + * within a namespace + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @gfp_mask: gfp mask for memory allocation + * @cleanup: a cleanup function + * @init: an init function + * @data: arbitrary context sensitive data + * @token: token used to locate namespace setup. + * + * Returns either an errno error cast, or a subprocess_info structure. + * This should be passed to call_usermodehelper_exec to exec the process + * and free the structure. + * + * The init function is used to customize the helper process prior to + * exec. A non-zero return code causes the process to error out, exit, + * and return the failure to the calling process + * + * The cleanup function is run just before the subprocess_info is about + * to be freed. This can be used for freeing the argv and envp. The + * Function must be runnable in either a process context or the + * context in which call_usermodehelper_exec is called. + */ +struct subprocess_info *call_usermodehelper_setup_ns(char *path, char **argv, + char **envp, gfp_t gfp_mask, + int (*init)(struct subprocess_info *info, struct cred *new), + void (*cleanup)(struct subprocess_info *info), + void *data, long token) +{ + struct subprocess_info *info; + unsigned int nowait = gfp_mask == GFP_ATOMIC ? 1 : 0; + struct umh_ns_entry *entry; + + info = call_usermodehelper_setup(path, argv, envp, + gfp_mask, NULL, NULL, NULL); + if (!info) + return ERR_PTR(-ENOMEM); + + entry = umh_ns_find_entry(token, nowait); + if (IS_ERR(entry)) { + kfree(info); + info = ERR_CAST(entry); + goto out; + } + get_nsproxy(entry->nsinfo.nsproxy); + info->nsinfo.nsproxy = entry->nsinfo.nsproxy; + info->nsinfo.user_ns = get_user_ns(entry->nsinfo.user_ns); +out: + return info; +} +EXPORT_SYMBOL(call_usermodehelper_setup_ns); +#endif /* CONFIG_NAMESPACES */ + /** * call_usermodehelper_exec - start a usermode application * @sub_info: information about the subprocessa @@ -939,6 +995,46 @@ int call_usermodehelper(char *path, } EXPORT_SYMBOL(call_usermodehelper); +#ifdef CONFIG_NAMESPACES +/** + * call_usermodehelper_ns() - prepare and start a usermode application and + * execute using the stored namspace information + * corresponding to the passed token + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @flags: wait for the application to finish and return status. + * when UMH_NO_WAIT don't wait at all, but you get no useful error back + * when the program couldn't be exec'ed. This makes it safe to call + * from interrupt context. + * @token: key of stored namespace to use or 0 to use the namespace of + * init process of the caller. + * + * Returns 0 or an errno error if not successful. + */ +int call_usermodehelper_ns(char *path, char **argv, char **envp, + unsigned int flags, long token) +{ + struct subprocess_info *info; + unsigned int nowait = flags & UMH_NO_WAIT; + gfp_t gfp_mask = nowait ? GFP_ATOMIC : GFP_KERNEL; + + if (token < 0) + return -EINVAL; + + if (!token) + return call_usermodehelper(path, argv, envp, flags|UMH_USE_NS); + + info = call_usermodehelper_setup_ns(path, argv, envp, + gfp_mask, NULL, NULL, NULL, token); + if (IS_ERR(info)) + return PTR_ERR(info); + + return call_usermodehelper_exec(info, flags|UMH_USE_NS); +} +EXPORT_SYMBOL(call_usermodehelper_ns); +#endif /* CONFIG_NAMESPACES */ + static int proc_cap_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
