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author | Eric Paris <eparis@redhat.com> | 2009-08-13 09:44:57 -0400 |
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committer | James Morris <jmorris@namei.org> | 2009-08-14 11:18:37 +1000 |
commit | 9188499cdb117d86a1ea6b04374095b098d56936 (patch) | |
tree | 7c0dd23f2c98630c426cbd0bfbf5e46cc689091e | |
parent | a8f80e8ff94ecba629542d9b4b5f5a8ee3eb565c (diff) | |
download | kernel_samsung_crespo-9188499cdb117d86a1ea6b04374095b098d56936.zip kernel_samsung_crespo-9188499cdb117d86a1ea6b04374095b098d56936.tar.gz kernel_samsung_crespo-9188499cdb117d86a1ea6b04374095b098d56936.tar.bz2 |
security: introducing security_request_module
Calling request_module() will trigger a userspace upcall which will load a
new module into the kernel. This can be a dangerous event if the process
able to trigger request_module() is able to control either the modprobe
binary or the module binary. This patch adds a new security hook to
request_module() which can be used by an LSM to control a processes ability
to call request_module().
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
-rw-r--r-- | include/linux/security.h | 10 | ||||
-rw-r--r-- | kernel/kmod.c | 4 | ||||
-rw-r--r-- | security/capability.c | 6 | ||||
-rw-r--r-- | security/security.c | 5 |
4 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index 57ead99..1e3dd86 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -678,6 +678,9 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @inode points to the inode to use as a reference. * The current task must be the one that nominated @inode. * Return 0 if successful. + * @kernel_module_request: + * Ability to trigger the kernel to automatically upcall to userspace for + * userspace to load a kernel module with the given name. * @task_setuid: * Check permission before setting one or more of the user identity * attributes of the current process. The @flags parameter indicates @@ -1489,6 +1492,7 @@ struct security_operations { void (*cred_commit)(struct cred *new, const struct cred *old); int (*kernel_act_as)(struct cred *new, u32 secid); int (*kernel_create_files_as)(struct cred *new, struct inode *inode); + int (*kernel_module_request)(void); int (*task_setuid) (uid_t id0, uid_t id1, uid_t id2, int flags); int (*task_fix_setuid) (struct cred *new, const struct cred *old, int flags); @@ -1741,6 +1745,7 @@ int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp); void security_commit_creds(struct cred *new, const struct cred *old); int security_kernel_act_as(struct cred *new, u32 secid); int security_kernel_create_files_as(struct cred *new, struct inode *inode); +int security_kernel_module_request(void); int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags); int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags); @@ -2292,6 +2297,11 @@ static inline int security_kernel_create_files_as(struct cred *cred, return 0; } +static inline int security_kernel_module_request(void) +{ + return 0; +} + static inline int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags) { diff --git a/kernel/kmod.c b/kernel/kmod.c index 385c31a..5a7ae57 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -78,6 +78,10 @@ int __request_module(bool wait, const char *fmt, ...) #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; + ret = security_kernel_module_request(); + if (ret) + return ret; + va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); diff --git a/security/capability.c b/security/capability.c index ec05730..1b943f5 100644 --- a/security/capability.c +++ b/security/capability.c @@ -396,6 +396,11 @@ static int cap_kernel_create_files_as(struct cred *new, struct inode *inode) return 0; } +static int cap_kernel_module_request(void) +{ + return 0; +} + static int cap_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags) { return 0; @@ -945,6 +950,7 @@ void security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, cred_commit); set_to_cap_if_null(ops, kernel_act_as); set_to_cap_if_null(ops, kernel_create_files_as); + set_to_cap_if_null(ops, kernel_module_request); set_to_cap_if_null(ops, task_setuid); set_to_cap_if_null(ops, task_fix_setuid); set_to_cap_if_null(ops, task_setgid); diff --git a/security/security.c b/security/security.c index 4501c5e..0e993f4 100644 --- a/security/security.c +++ b/security/security.c @@ -709,6 +709,11 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode) return security_ops->kernel_create_files_as(new, inode); } +int security_kernel_module_request(void) +{ + return security_ops->kernel_module_request(); +} + int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags) { return security_ops->task_setuid(id0, id1, id2, flags); |