| Message ID | 20190621185233.6766-16-casey@schaufler-ca.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | LSM: Module stacking for AppArmor | expand |
On Fri, Jun 21, 2019 at 11:52:24AM -0700, Casey Schaufler wrote: > Create a new entry "display" in /proc/.../attr for controlling > which LSM security information is displayed for a process. > The name of an active LSM that supplies hooks for human readable > data may be written to "display" to set the value. The name of > the LSM currently in use can be read from "display". > At this point there can only be one LSM capable of display > active. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > --- > fs/proc/base.c | 1 + > security/security.c | 110 +++++++++++++++++++++++++++++++++++--------- > 2 files changed, 90 insertions(+), 21 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index ddef482f1334..7bf70e041315 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -2618,6 +2618,7 @@ static const struct pid_entry attr_dir_stuff[] = { > ATTR(NULL, "fscreate", 0666), > ATTR(NULL, "keycreate", 0666), > ATTR(NULL, "sockcreate", 0666), > + ATTR(NULL, "display", 0666), > #ifdef CONFIG_SECURITY_SMACK > DIR("smack", 0555, > proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops), > diff --git a/security/security.c b/security/security.c > index aa8e1c73a062..92c5aa427b53 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -46,7 +46,9 @@ static struct kmem_cache *lsm_file_cache; > static struct kmem_cache *lsm_inode_cache; > > char *lsm_names; > -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init; > +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = { > + .lbs_task = sizeof(int), /* slot number for the "display" LSM */ > +}; > > /* Boot-time LSM user choice */ > static __initdata const char *chosen_lsm_order; > @@ -583,6 +585,8 @@ int lsm_inode_alloc(struct inode *inode) > */ > static int lsm_task_alloc(struct task_struct *task) > { > + int *display; > + > if (blob_sizes.lbs_task == 0) { > task->security = NULL; > return 0; > @@ -591,6 +595,15 @@ static int lsm_task_alloc(struct task_struct *task) > task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL); > if (task->security == NULL) > return -ENOMEM; > + > + /* > + * The start of the task blob contains the "display" LSM slot number. > + * Start with it set to the invalid slot number, indicating that the > + * default first registered LSM be displayed. > + */ > + display = task->security; > + *display = LSMBLOB_INVALID; > + > return 0; > } > > @@ -1579,14 +1592,24 @@ int security_file_open(struct file *file) > > int security_task_alloc(struct task_struct *task, unsigned long clone_flags) > { > + int *odisplay = current->security; > + int *ndisplay; > int rc = lsm_task_alloc(task); > > - if (rc) > + if (unlikely(rc)) > return rc; > + > rc = call_int_hook(task_alloc, 0, task, clone_flags); > - if (unlikely(rc)) > + if (unlikely(rc)) { > security_task_free(task); > - return rc; > + return rc; > + } > + > + ndisplay = task->security; > + if (ndisplay && odisplay) > + *ndisplay = *odisplay; > + > + return 0; > } > > void security_task_free(struct task_struct *task) > @@ -1972,10 +1995,28 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, > char **value) > { > struct security_hook_list *hp; > + int *display = current->security; > + > + if (!strcmp(name, "display")) { > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, > + list) { > + if (*display == LSMBLOB_INVALID || > + hp->slot == *display) { > + *value = kstrdup(hp->lsm, GFP_KERNEL); > + if (*value) > + return strlen(hp->lsm); > + return -ENOMEM; > + } > + } > + return -EINVAL; > + } > > hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { > if (lsm != NULL && strcmp(lsm, hp->lsm)) > continue; > + if (lsm == NULL && *display != LSMBLOB_INVALID && > + *display != hp->slot) > + continue; > return hp->hook.getprocattr(p, name, value); > } > return -EINVAL; > @@ -1985,10 +2026,27 @@ int security_setprocattr(const char *lsm, const char *name, void *value, > size_t size) > { > struct security_hook_list *hp; > + int *display = current->security; > + int len; > + > + if (!strcmp(name, "display")) { > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, > + list) { > + len = strlen(hp->lsm); > + if (size >= len && !strncmp(value, hp->lsm, len)) { > + *display = hp->slot; > + return size; > + } > + } > + return -EINVAL; > + } > > hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { > if (lsm != NULL && strcmp(lsm, hp->lsm)) > continue; > + if (lsm == NULL && *display != LSMBLOB_INVALID && > + *display != hp->slot) > + continue; > return hp->hook.setprocattr(name, value, size); > } > return -EINVAL; > @@ -2008,14 +2066,12 @@ EXPORT_SYMBOL(security_ismaclabel); > int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen) > { > struct security_hook_list *hp; > - int rc; > + int *display = current->security; > > - hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) { > - rc = hp->hook.secid_to_secctx(blob->secid[hp->slot], > - secdata, seclen); > - if (rc != 0) > - return rc; > - } > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.secid_to_secctx(blob->secid[hp->slot], > + secdata, seclen); > return 0; > } > EXPORT_SYMBOL(security_secid_to_secctx); > @@ -2024,22 +2080,27 @@ int security_secctx_to_secid(const char *secdata, u32 seclen, > struct lsmblob *blob) > { > struct security_hook_list *hp; > - int rc; > + int *display = current->security; > > lsmblob_init(blob, 0); > - hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) { > - rc = hp->hook.secctx_to_secid(secdata, seclen, > - &blob->secid[hp->slot]); > - if (rc != 0) > - return rc; > - } > + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.secctx_to_secid(secdata, seclen, > + &blob->secid[hp->slot]); > return 0; > } > EXPORT_SYMBOL(security_secctx_to_secid); > > void security_release_secctx(char *secdata, u32 seclen) > { > - call_void_hook(release_secctx, secdata, seclen); > + struct security_hook_list *hp; > + int *display = current->security; > + > + hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) { > + hp->hook.release_secctx(secdata, seclen); > + return; > + } > } > EXPORT_SYMBOL(security_release_secctx); > > @@ -2164,8 +2225,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb); > int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, > int __user *optlen, unsigned len) > { > - return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock, > - optval, optlen, len); > + int *display = current->security; > + struct security_hook_list *hp; > + > + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream, > + list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.socket_getpeersec_stream(sock, optval, > + optlen, len); > + return -ENOPROTOOPT; > } > > int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, > -- > 2.20.1 >
On 6/21/19 11:52 AM, Casey Schaufler wrote: > Create a new entry "display" in /proc/.../attr for controlling > which LSM security information is displayed for a process. > The name of an active LSM that supplies hooks for human readable > data may be written to "display" to set the value. The name of > the LSM currently in use can be read from "display". > At this point there can only be one LSM capable of display > active. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> there is small issue, see below Also I want to get rid of the list search for the display lsm but that can come as a separate patch later > --- > fs/proc/base.c | 1 + > security/security.c | 110 +++++++++++++++++++++++++++++++++++--------- > 2 files changed, 90 insertions(+), 21 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index ddef482f1334..7bf70e041315 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -2618,6 +2618,7 @@ static const struct pid_entry attr_dir_stuff[] = { > ATTR(NULL, "fscreate", 0666), > ATTR(NULL, "keycreate", 0666), > ATTR(NULL, "sockcreate", 0666), > + ATTR(NULL, "display", 0666), > #ifdef CONFIG_SECURITY_SMACK > DIR("smack", 0555, > proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops), > diff --git a/security/security.c b/security/security.c > index aa8e1c73a062..92c5aa427b53 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -46,7 +46,9 @@ static struct kmem_cache *lsm_file_cache; > static struct kmem_cache *lsm_inode_cache; > > char *lsm_names; > -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init; > +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = { > + .lbs_task = sizeof(int), /* slot number for the "display" LSM */ > +}; > > /* Boot-time LSM user choice */ > static __initdata const char *chosen_lsm_order; > @@ -583,6 +585,8 @@ int lsm_inode_alloc(struct inode *inode) > */ > static int lsm_task_alloc(struct task_struct *task) > { > + int *display; > + > if (blob_sizes.lbs_task == 0) { > task->security = NULL; > return 0; > @@ -591,6 +595,15 @@ static int lsm_task_alloc(struct task_struct *task) > task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL); > if (task->security == NULL) > return -ENOMEM; > + > + /* > + * The start of the task blob contains the "display" LSM slot number. > + * Start with it set to the invalid slot number, indicating that the > + * default first registered LSM be displayed. > + */ > + display = task->security; > + *display = LSMBLOB_INVALID; > + > return 0; > } > > @@ -1579,14 +1592,24 @@ int security_file_open(struct file *file) > > int security_task_alloc(struct task_struct *task, unsigned long clone_flags) > { > + int *odisplay = current->security; > + int *ndisplay; > int rc = lsm_task_alloc(task); > > - if (rc) > + if (unlikely(rc)) > return rc; > + > rc = call_int_hook(task_alloc, 0, task, clone_flags); > - if (unlikely(rc)) > + if (unlikely(rc)) { > security_task_free(task); > - return rc; > + return rc; > + } > + > + ndisplay = task->security; > + if (ndisplay && odisplay) > + *ndisplay = *odisplay; > + > + return 0; > } > > void security_task_free(struct task_struct *task) > @@ -1972,10 +1995,28 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, > char **value) > { > struct security_hook_list *hp; > + int *display = current->security; > + > + if (!strcmp(name, "display")) { > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, > + list) { > + if (*display == LSMBLOB_INVALID || > + hp->slot == *display) { > + *value = kstrdup(hp->lsm, GFP_KERNEL); > + if (*value) > + return strlen(hp->lsm); > + return -ENOMEM; > + } > + } > + return -EINVAL; > + } > > hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { > if (lsm != NULL && strcmp(lsm, hp->lsm)) > continue; > + if (lsm == NULL && *display != LSMBLOB_INVALID && > + *display != hp->slot) > + continue; > return hp->hook.getprocattr(p, name, value); > } > return -EINVAL; > @@ -1985,10 +2026,27 @@ int security_setprocattr(const char *lsm, const char *name, void *value, > size_t size) > { > struct security_hook_list *hp; > + int *display = current->security; > + int len; > + > + if (!strcmp(name, "display")) { > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, > + list) { > + len = strlen(hp->lsm); > + if (size >= len && !strncmp(value, hp->lsm, len)) { This isn't quite right. It allows a value that contains a prefix of an lsm to match. That is selinux2 etc would match to selinux. While it isn't a real problem atm. Its not something I want as part of the user space API which would make it so we can't fix it. > + *display = hp->slot; > + return size; > + } > + } > + return -EINVAL; > + } > > hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { > if (lsm != NULL && strcmp(lsm, hp->lsm)) > continue; > + if (lsm == NULL && *display != LSMBLOB_INVALID && > + *display != hp->slot) > + continue; > return hp->hook.setprocattr(name, value, size); > } > return -EINVAL; > @@ -2008,14 +2066,12 @@ EXPORT_SYMBOL(security_ismaclabel); > int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen) > { > struct security_hook_list *hp; > - int rc; > + int *display = current->security; > > - hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) { > - rc = hp->hook.secid_to_secctx(blob->secid[hp->slot], > - secdata, seclen); > - if (rc != 0) > - return rc; > - } > + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.secid_to_secctx(blob->secid[hp->slot], > + secdata, seclen); > return 0; > } > EXPORT_SYMBOL(security_secid_to_secctx); > @@ -2024,22 +2080,27 @@ int security_secctx_to_secid(const char *secdata, u32 seclen, > struct lsmblob *blob) > { > struct security_hook_list *hp; > - int rc; > + int *display = current->security; > > lsmblob_init(blob, 0); > - hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) { > - rc = hp->hook.secctx_to_secid(secdata, seclen, > - &blob->secid[hp->slot]); > - if (rc != 0) > - return rc; > - } > + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.secctx_to_secid(secdata, seclen, > + &blob->secid[hp->slot]); > return 0; > } > EXPORT_SYMBOL(security_secctx_to_secid); > > void security_release_secctx(char *secdata, u32 seclen) > { > - call_void_hook(release_secctx, secdata, seclen); > + struct security_hook_list *hp; > + int *display = current->security; > + > + hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) { > + hp->hook.release_secctx(secdata, seclen); > + return; > + } > } > EXPORT_SYMBOL(security_release_secctx); > > @@ -2164,8 +2225,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb); > int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, > int __user *optlen, unsigned len) > { > - return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock, > - optval, optlen, len); > + int *display = current->security; > + struct security_hook_list *hp; > + > + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream, > + list) > + if (*display == LSMBLOB_INVALID || *display == hp->slot) > + return hp->hook.socket_getpeersec_stream(sock, optval, > + optlen, len); > + return -ENOPROTOOPT; > } > > int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, >
diff --git a/fs/proc/base.c b/fs/proc/base.c index ddef482f1334..7bf70e041315 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2618,6 +2618,7 @@ static const struct pid_entry attr_dir_stuff[] = { ATTR(NULL, "fscreate", 0666), ATTR(NULL, "keycreate", 0666), ATTR(NULL, "sockcreate", 0666), + ATTR(NULL, "display", 0666), #ifdef CONFIG_SECURITY_SMACK DIR("smack", 0555, proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops), diff --git a/security/security.c b/security/security.c index aa8e1c73a062..92c5aa427b53 100644 --- a/security/security.c +++ b/security/security.c @@ -46,7 +46,9 @@ static struct kmem_cache *lsm_file_cache; static struct kmem_cache *lsm_inode_cache; char *lsm_names; -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init; +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = { + .lbs_task = sizeof(int), /* slot number for the "display" LSM */ +}; /* Boot-time LSM user choice */ static __initdata const char *chosen_lsm_order; @@ -583,6 +585,8 @@ int lsm_inode_alloc(struct inode *inode) */ static int lsm_task_alloc(struct task_struct *task) { + int *display; + if (blob_sizes.lbs_task == 0) { task->security = NULL; return 0; @@ -591,6 +595,15 @@ static int lsm_task_alloc(struct task_struct *task) task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL); if (task->security == NULL) return -ENOMEM; + + /* + * The start of the task blob contains the "display" LSM slot number. + * Start with it set to the invalid slot number, indicating that the + * default first registered LSM be displayed. + */ + display = task->security; + *display = LSMBLOB_INVALID; + return 0; } @@ -1579,14 +1592,24 @@ int security_file_open(struct file *file) int security_task_alloc(struct task_struct *task, unsigned long clone_flags) { + int *odisplay = current->security; + int *ndisplay; int rc = lsm_task_alloc(task); - if (rc) + if (unlikely(rc)) return rc; + rc = call_int_hook(task_alloc, 0, task, clone_flags); - if (unlikely(rc)) + if (unlikely(rc)) { security_task_free(task); - return rc; + return rc; + } + + ndisplay = task->security; + if (ndisplay && odisplay) + *ndisplay = *odisplay; + + return 0; } void security_task_free(struct task_struct *task) @@ -1972,10 +1995,28 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, char **value) { struct security_hook_list *hp; + int *display = current->security; + + if (!strcmp(name, "display")) { + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, + list) { + if (*display == LSMBLOB_INVALID || + hp->slot == *display) { + *value = kstrdup(hp->lsm, GFP_KERNEL); + if (*value) + return strlen(hp->lsm); + return -ENOMEM; + } + } + return -EINVAL; + } hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { if (lsm != NULL && strcmp(lsm, hp->lsm)) continue; + if (lsm == NULL && *display != LSMBLOB_INVALID && + *display != hp->slot) + continue; return hp->hook.getprocattr(p, name, value); } return -EINVAL; @@ -1985,10 +2026,27 @@ int security_setprocattr(const char *lsm, const char *name, void *value, size_t size) { struct security_hook_list *hp; + int *display = current->security; + int len; + + if (!strcmp(name, "display")) { + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, + list) { + len = strlen(hp->lsm); + if (size >= len && !strncmp(value, hp->lsm, len)) { + *display = hp->slot; + return size; + } + } + return -EINVAL; + } hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { if (lsm != NULL && strcmp(lsm, hp->lsm)) continue; + if (lsm == NULL && *display != LSMBLOB_INVALID && + *display != hp->slot) + continue; return hp->hook.setprocattr(name, value, size); } return -EINVAL; @@ -2008,14 +2066,12 @@ EXPORT_SYMBOL(security_ismaclabel); int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen) { struct security_hook_list *hp; - int rc; + int *display = current->security; - hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) { - rc = hp->hook.secid_to_secctx(blob->secid[hp->slot], - secdata, seclen); - if (rc != 0) - return rc; - } + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) + if (*display == LSMBLOB_INVALID || *display == hp->slot) + return hp->hook.secid_to_secctx(blob->secid[hp->slot], + secdata, seclen); return 0; } EXPORT_SYMBOL(security_secid_to_secctx); @@ -2024,22 +2080,27 @@ int security_secctx_to_secid(const char *secdata, u32 seclen, struct lsmblob *blob) { struct security_hook_list *hp; - int rc; + int *display = current->security; lsmblob_init(blob, 0); - hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) { - rc = hp->hook.secctx_to_secid(secdata, seclen, - &blob->secid[hp->slot]); - if (rc != 0) - return rc; - } + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) + if (*display == LSMBLOB_INVALID || *display == hp->slot) + return hp->hook.secctx_to_secid(secdata, seclen, + &blob->secid[hp->slot]); return 0; } EXPORT_SYMBOL(security_secctx_to_secid); void security_release_secctx(char *secdata, u32 seclen) { - call_void_hook(release_secctx, secdata, seclen); + struct security_hook_list *hp; + int *display = current->security; + + hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list) + if (*display == LSMBLOB_INVALID || *display == hp->slot) { + hp->hook.release_secctx(secdata, seclen); + return; + } } EXPORT_SYMBOL(security_release_secctx); @@ -2164,8 +2225,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb); int security_socket_getpeersec_stream(struct socket *sock, char __user *optval, int __user *optlen, unsigned len) { - return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock, - optval, optlen, len); + int *display = current->security; + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream, + list) + if (*display == LSMBLOB_INVALID || *display == hp->slot) + return hp->hook.socket_getpeersec_stream(sock, optval, + optlen, len); + return -ENOPROTOOPT; } int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
Create a new entry "display" in /proc/.../attr for controlling which LSM security information is displayed for a process. The name of an active LSM that supplies hooks for human readable data may be written to "display" to set the value. The name of the LSM currently in use can be read from "display". At this point there can only be one LSM capable of display active. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- fs/proc/base.c | 1 + security/security.c | 110 +++++++++++++++++++++++++++++++++++--------- 2 files changed, 90 insertions(+), 21 deletions(-)