* [PATCH 1/2] LSM: SafeSetID: gate setgid transitions
@ 2019-02-15 22:22 mortonm
2019-02-16 16:43 ` Serge E. Hallyn
0 siblings, 1 reply; 4+ messages in thread
From: mortonm @ 2019-02-15 22:22 UTC (permalink / raw)
To: jmorris, serge, keescook, casey, sds, linux-security-module; +Cc: Micah Morton
From: Micah Morton <mortonm@chromium.org>
This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the
existing 'task_fix_setuid' LSM hook, and calls this new hook from the
setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to
govern setgid transitions in addition to setuid transitions. This change
also makes sure the setgid functions in kernel/sys.c call
security_capable_setid rather than the ordinary security_capable
function, so that the security_capable hook in the SafeSetID LSM knows
it is being invoked from a setid function.
Signed-off-by: Micah Morton <mortonm@chromium.org>
---
Tested with slight mod to test in tools/testing/selftests/safesetid for
testing setgid as well as setuid.
include/linux/lsm_hooks.h | 12 ++++++++++++
include/linux/security.h | 10 ++++++++++
kernel/sys.c | 27 +++++++++++++++++++++------
security/security.c | 6 ++++++
4 files changed, 49 insertions(+), 6 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 22fc786d723a..f252ed3e95ef 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -603,6 +603,15 @@
* @old is the set of credentials that are being replaces
* @flags contains one of the LSM_SETID_* values.
* Return 0 on success.
+ * @task_fix_setgid:
+ * Update the module's state after setting one or more of the group
+ * identity attributes of the current process. The @flags parameter
+ * indicates which of the set*gid system calls invoked this hook.
+ * @new is the set of credentials that will be installed. Modifications
+ * should be made to this rather than to @current->cred.
+ * @old is the set of credentials that are being replaced
+ * @flags contains one of the LSM_SETID_* values.
+ * Return 0 on success.
* @task_setpgid:
* Check permission before setting the process group identifier of the
* process @p to @pgid.
@@ -1596,6 +1605,8 @@ union security_list_options {
enum kernel_read_file_id id);
int (*task_fix_setuid)(struct cred *new, const struct cred *old,
int flags);
+ int (*task_fix_setgid)(struct cred *new, const struct cred *old,
+ int flags);
int (*task_setpgid)(struct task_struct *p, pid_t pgid);
int (*task_getpgid)(struct task_struct *p);
int (*task_getsid)(struct task_struct *p);
@@ -1887,6 +1898,7 @@ struct security_hook_heads {
struct hlist_head kernel_post_read_file;
struct hlist_head kernel_module_request;
struct hlist_head task_fix_setuid;
+ struct hlist_head task_fix_setgid;
struct hlist_head task_setpgid;
struct hlist_head task_getpgid;
struct hlist_head task_getsid;
diff --git a/include/linux/security.h b/include/linux/security.h
index 13537a49ae97..f3d095e8dfc1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr);
extern int cap_mmap_file(struct file *file, unsigned long reqprot,
unsigned long prot, unsigned long flags);
extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
+extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags);
extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5);
extern int cap_task_setscheduler(struct task_struct *p);
@@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
enum kernel_read_file_id id);
int security_task_fix_setuid(struct cred *new, const struct cred *old,
int flags);
+int security_task_fix_setgid(struct cred *new, const struct cred *old,
+ int flags);
int security_task_setpgid(struct task_struct *p, pid_t pgid);
int security_task_getpgid(struct task_struct *p);
int security_task_getsid(struct task_struct *p);
@@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new,
return cap_task_fix_setuid(new, old, flags);
}
+static inline int security_task_fix_setgid(struct cred *new,
+ const struct cred *old,
+ int flags)
+{
+ return cap_task_fix_setgid(new, old, flags);
+}
+
static inline int security_task_setpgid(struct task_struct *p, pid_t pgid)
{
return 0;
diff --git a/kernel/sys.c b/kernel/sys.c
index c5f875048aef..76f1c46ac66f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
if (rgid != (gid_t) -1) {
if (gid_eq(old->gid, krgid) ||
gid_eq(old->egid, krgid) ||
- ns_capable(old->user_ns, CAP_SETGID))
+ ns_capable_setid(old->user_ns, CAP_SETGID))
new->gid = krgid;
else
goto error;
@@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
if (gid_eq(old->gid, kegid) ||
gid_eq(old->egid, kegid) ||
gid_eq(old->sgid, kegid) ||
- ns_capable(old->user_ns, CAP_SETGID))
+ ns_capable_setid(old->user_ns, CAP_SETGID))
new->egid = kegid;
else
goto error;
@@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid)
new->sgid = new->egid;
new->fsgid = new->egid;
+ retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
+ if (retval < 0)
+ goto error;
+
return commit_creds(new);
error:
@@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid)
old = current_cred();
retval = -EPERM;
- if (ns_capable(old->user_ns, CAP_SETGID))
+ if (ns_capable_setid(old->user_ns, CAP_SETGID))
new->gid = new->egid = new->sgid = new->fsgid = kgid;
else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
new->egid = new->fsgid = kgid;
else
goto error;
+ retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
+ if (retval < 0)
+ goto error;
+
return commit_creds(new);
error:
@@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
old = current_cred();
retval = -EPERM;
- if (!ns_capable(old->user_ns, CAP_SETGID)) {
+ if (!ns_capable_setid(old->user_ns, CAP_SETGID)) {
if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
!gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
goto error;
@@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
new->sgid = ksgid;
new->fsgid = new->egid;
+ retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
+ if (retval < 0)
+ goto error;
+
return commit_creds(new);
error:
@@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid)
if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
- ns_capable(old->user_ns, CAP_SETGID)) {
+ ns_capable_setid(old->user_ns, CAP_SETGID)) {
if (!gid_eq(kgid, old->fsgid)) {
new->fsgid = kgid;
- goto change_okay;
+ if (security_task_fix_setgid(new,
+ old,
+ LSM_SETID_FS) == 0)
+ goto change_okay;
}
}
diff --git a/security/security.c b/security/security.c
index b6bff646d373..4264a1e77ce8 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
return call_int_hook(task_fix_setuid, 0, new, old, flags);
}
+int security_task_fix_setgid(struct cred *new, const struct cred *old,
+ int flags)
+{
+ return call_int_hook(task_fix_setgid, 0, new, old, flags);
+}
+
int security_task_setpgid(struct task_struct *p, pid_t pgid)
{
return call_int_hook(task_setpgid, 0, p, pgid);
--
2.21.0.rc0.258.g878e2cd30e-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] LSM: SafeSetID: gate setgid transitions
2019-02-15 22:22 [PATCH 1/2] LSM: SafeSetID: gate setgid transitions mortonm
@ 2019-02-16 16:43 ` Serge E. Hallyn
2019-02-19 17:00 ` Micah Morton
0 siblings, 1 reply; 4+ messages in thread
From: Serge E. Hallyn @ 2019-02-16 16:43 UTC (permalink / raw)
To: mortonm; +Cc: jmorris, serge, keescook, casey, sds, linux-security-module
On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote:
> From: Micah Morton <mortonm@chromium.org>
>
> This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the
> existing 'task_fix_setuid' LSM hook, and calls this new hook from the
> setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to
> govern setgid transitions in addition to setuid transitions. This change
> also makes sure the setgid functions in kernel/sys.c call
> security_capable_setid rather than the ordinary security_capable
Sorry, where security_capable_setid this defined? I assume it was in a recent
patchset, but google and grep are failing me.
> function, so that the security_capable hook in the SafeSetID LSM knows
> it is being invoked from a setid function.
>
> Signed-off-by: Micah Morton <mortonm@chromium.org>
> ---
> Tested with slight mod to test in tools/testing/selftests/safesetid for
> testing setgid as well as setuid.
>
> include/linux/lsm_hooks.h | 12 ++++++++++++
> include/linux/security.h | 10 ++++++++++
> kernel/sys.c | 27 +++++++++++++++++++++------
> security/security.c | 6 ++++++
> 4 files changed, 49 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 22fc786d723a..f252ed3e95ef 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -603,6 +603,15 @@
> * @old is the set of credentials that are being replaces
> * @flags contains one of the LSM_SETID_* values.
> * Return 0 on success.
> + * @task_fix_setgid:
> + * Update the module's state after setting one or more of the group
> + * identity attributes of the current process. The @flags parameter
> + * indicates which of the set*gid system calls invoked this hook.
> + * @new is the set of credentials that will be installed. Modifications
> + * should be made to this rather than to @current->cred.
> + * @old is the set of credentials that are being replaced
> + * @flags contains one of the LSM_SETID_* values.
> + * Return 0 on success.
> * @task_setpgid:
> * Check permission before setting the process group identifier of the
> * process @p to @pgid.
> @@ -1596,6 +1605,8 @@ union security_list_options {
> enum kernel_read_file_id id);
> int (*task_fix_setuid)(struct cred *new, const struct cred *old,
> int flags);
> + int (*task_fix_setgid)(struct cred *new, const struct cred *old,
> + int flags);
> int (*task_setpgid)(struct task_struct *p, pid_t pgid);
> int (*task_getpgid)(struct task_struct *p);
> int (*task_getsid)(struct task_struct *p);
> @@ -1887,6 +1898,7 @@ struct security_hook_heads {
> struct hlist_head kernel_post_read_file;
> struct hlist_head kernel_module_request;
> struct hlist_head task_fix_setuid;
> + struct hlist_head task_fix_setgid;
> struct hlist_head task_setpgid;
> struct hlist_head task_getpgid;
> struct hlist_head task_getsid;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 13537a49ae97..f3d095e8dfc1 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr);
> extern int cap_mmap_file(struct file *file, unsigned long reqprot,
> unsigned long prot, unsigned long flags);
> extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
> +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags);
> extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> unsigned long arg4, unsigned long arg5);
> extern int cap_task_setscheduler(struct task_struct *p);
> @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
> enum kernel_read_file_id id);
> int security_task_fix_setuid(struct cred *new, const struct cred *old,
> int flags);
> +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> + int flags);
> int security_task_setpgid(struct task_struct *p, pid_t pgid);
> int security_task_getpgid(struct task_struct *p);
> int security_task_getsid(struct task_struct *p);
> @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new,
> return cap_task_fix_setuid(new, old, flags);
> }
>
> +static inline int security_task_fix_setgid(struct cred *new,
> + const struct cred *old,
> + int flags)
> +{
> + return cap_task_fix_setgid(new, old, flags);
> +}
> +
> static inline int security_task_setpgid(struct task_struct *p, pid_t pgid)
> {
> return 0;
> diff --git a/kernel/sys.c b/kernel/sys.c
> index c5f875048aef..76f1c46ac66f 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> if (rgid != (gid_t) -1) {
> if (gid_eq(old->gid, krgid) ||
> gid_eq(old->egid, krgid) ||
> - ns_capable(old->user_ns, CAP_SETGID))
> + ns_capable_setid(old->user_ns, CAP_SETGID))
> new->gid = krgid;
> else
> goto error;
> @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> if (gid_eq(old->gid, kegid) ||
> gid_eq(old->egid, kegid) ||
> gid_eq(old->sgid, kegid) ||
> - ns_capable(old->user_ns, CAP_SETGID))
> + ns_capable_setid(old->user_ns, CAP_SETGID))
> new->egid = kegid;
> else
> goto error;
> @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> new->sgid = new->egid;
> new->fsgid = new->egid;
>
> + retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
> + if (retval < 0)
> + goto error;
> +
> return commit_creds(new);
>
> error:
> @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid)
> old = current_cred();
>
> retval = -EPERM;
> - if (ns_capable(old->user_ns, CAP_SETGID))
> + if (ns_capable_setid(old->user_ns, CAP_SETGID))
> new->gid = new->egid = new->sgid = new->fsgid = kgid;
> else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
> new->egid = new->fsgid = kgid;
> else
> goto error;
>
> + retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
> + if (retval < 0)
> + goto error;
> +
> return commit_creds(new);
>
> error:
> @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> old = current_cred();
>
> retval = -EPERM;
> - if (!ns_capable(old->user_ns, CAP_SETGID)) {
> + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) {
> if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
> !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
> goto error;
> @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> new->sgid = ksgid;
> new->fsgid = new->egid;
>
> + retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
> + if (retval < 0)
> + goto error;
> +
> return commit_creds(new);
>
> error:
> @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid)
>
> if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
> gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
> - ns_capable(old->user_ns, CAP_SETGID)) {
> + ns_capable_setid(old->user_ns, CAP_SETGID)) {
> if (!gid_eq(kgid, old->fsgid)) {
> new->fsgid = kgid;
> - goto change_okay;
> + if (security_task_fix_setgid(new,
> + old,
> + LSM_SETID_FS) == 0)
> + goto change_okay;
> }
> }
>
> diff --git a/security/security.c b/security/security.c
> index b6bff646d373..4264a1e77ce8 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
> return call_int_hook(task_fix_setuid, 0, new, old, flags);
> }
>
> +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> + int flags)
> +{
> + return call_int_hook(task_fix_setgid, 0, new, old, flags);
> +}
> +
> int security_task_setpgid(struct task_struct *p, pid_t pgid)
> {
> return call_int_hook(task_setpgid, 0, p, pgid);
> --
> 2.21.0.rc0.258.g878e2cd30e-goog
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] LSM: SafeSetID: gate setgid transitions
2019-02-16 16:43 ` Serge E. Hallyn
@ 2019-02-19 17:00 ` Micah Morton
2019-02-19 18:20 ` Serge E. Hallyn
0 siblings, 1 reply; 4+ messages in thread
From: Micah Morton @ 2019-02-19 17:00 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: James Morris, Kees Cook, Casey Schaufler, Stephen Smalley,
linux-security-module
On Sat, Feb 16, 2019 at 8:43 AM Serge E. Hallyn <serge@hallyn.com> wrote:
>
> On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote:
> > From: Micah Morton <mortonm@chromium.org>
> >
> > This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the
> > existing 'task_fix_setuid' LSM hook, and calls this new hook from the
> > setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to
> > govern setgid transitions in addition to setuid transitions. This change
> > also makes sure the setgid functions in kernel/sys.c call
> > security_capable_setid rather than the ordinary security_capable
>
> Sorry, where security_capable_setid this defined? I assume it was in a recent
> patchset, but google and grep are failing me.
It was defined in commit 40852275a94afb3e836be9248399e036982d1a79 on
the origin/next-general branch of
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git.
>
> > function, so that the security_capable hook in the SafeSetID LSM knows
> > it is being invoked from a setid function.
> >
> > Signed-off-by: Micah Morton <mortonm@chromium.org>
> > ---
> > Tested with slight mod to test in tools/testing/selftests/safesetid for
> > testing setgid as well as setuid.
> >
> > include/linux/lsm_hooks.h | 12 ++++++++++++
> > include/linux/security.h | 10 ++++++++++
> > kernel/sys.c | 27 +++++++++++++++++++++------
> > security/security.c | 6 ++++++
> > 4 files changed, 49 insertions(+), 6 deletions(-)
> >
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index 22fc786d723a..f252ed3e95ef 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -603,6 +603,15 @@
> > * @old is the set of credentials that are being replaces
> > * @flags contains one of the LSM_SETID_* values.
> > * Return 0 on success.
> > + * @task_fix_setgid:
> > + * Update the module's state after setting one or more of the group
> > + * identity attributes of the current process. The @flags parameter
> > + * indicates which of the set*gid system calls invoked this hook.
> > + * @new is the set of credentials that will be installed. Modifications
> > + * should be made to this rather than to @current->cred.
> > + * @old is the set of credentials that are being replaced
> > + * @flags contains one of the LSM_SETID_* values.
> > + * Return 0 on success.
> > * @task_setpgid:
> > * Check permission before setting the process group identifier of the
> > * process @p to @pgid.
> > @@ -1596,6 +1605,8 @@ union security_list_options {
> > enum kernel_read_file_id id);
> > int (*task_fix_setuid)(struct cred *new, const struct cred *old,
> > int flags);
> > + int (*task_fix_setgid)(struct cred *new, const struct cred *old,
> > + int flags);
> > int (*task_setpgid)(struct task_struct *p, pid_t pgid);
> > int (*task_getpgid)(struct task_struct *p);
> > int (*task_getsid)(struct task_struct *p);
> > @@ -1887,6 +1898,7 @@ struct security_hook_heads {
> > struct hlist_head kernel_post_read_file;
> > struct hlist_head kernel_module_request;
> > struct hlist_head task_fix_setuid;
> > + struct hlist_head task_fix_setgid;
> > struct hlist_head task_setpgid;
> > struct hlist_head task_getpgid;
> > struct hlist_head task_getsid;
> > diff --git a/include/linux/security.h b/include/linux/security.h
> > index 13537a49ae97..f3d095e8dfc1 100644
> > --- a/include/linux/security.h
> > +++ b/include/linux/security.h
> > @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr);
> > extern int cap_mmap_file(struct file *file, unsigned long reqprot,
> > unsigned long prot, unsigned long flags);
> > extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
> > +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags);
> > extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> > unsigned long arg4, unsigned long arg5);
> > extern int cap_task_setscheduler(struct task_struct *p);
> > @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
> > enum kernel_read_file_id id);
> > int security_task_fix_setuid(struct cred *new, const struct cred *old,
> > int flags);
> > +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> > + int flags);
> > int security_task_setpgid(struct task_struct *p, pid_t pgid);
> > int security_task_getpgid(struct task_struct *p);
> > int security_task_getsid(struct task_struct *p);
> > @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new,
> > return cap_task_fix_setuid(new, old, flags);
> > }
> >
> > +static inline int security_task_fix_setgid(struct cred *new,
> > + const struct cred *old,
> > + int flags)
> > +{
> > + return cap_task_fix_setgid(new, old, flags);
> > +}
> > +
> > static inline int security_task_setpgid(struct task_struct *p, pid_t pgid)
> > {
> > return 0;
> > diff --git a/kernel/sys.c b/kernel/sys.c
> > index c5f875048aef..76f1c46ac66f 100644
> > --- a/kernel/sys.c
> > +++ b/kernel/sys.c
> > @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > if (rgid != (gid_t) -1) {
> > if (gid_eq(old->gid, krgid) ||
> > gid_eq(old->egid, krgid) ||
> > - ns_capable(old->user_ns, CAP_SETGID))
> > + ns_capable_setid(old->user_ns, CAP_SETGID))
> > new->gid = krgid;
> > else
> > goto error;
> > @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > if (gid_eq(old->gid, kegid) ||
> > gid_eq(old->egid, kegid) ||
> > gid_eq(old->sgid, kegid) ||
> > - ns_capable(old->user_ns, CAP_SETGID))
> > + ns_capable_setid(old->user_ns, CAP_SETGID))
> > new->egid = kegid;
> > else
> > goto error;
> > @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > new->sgid = new->egid;
> > new->fsgid = new->egid;
> >
> > + retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
> > + if (retval < 0)
> > + goto error;
> > +
> > return commit_creds(new);
> >
> > error:
> > @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid)
> > old = current_cred();
> >
> > retval = -EPERM;
> > - if (ns_capable(old->user_ns, CAP_SETGID))
> > + if (ns_capable_setid(old->user_ns, CAP_SETGID))
> > new->gid = new->egid = new->sgid = new->fsgid = kgid;
> > else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
> > new->egid = new->fsgid = kgid;
> > else
> > goto error;
> >
> > + retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
> > + if (retval < 0)
> > + goto error;
> > +
> > return commit_creds(new);
> >
> > error:
> > @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> > old = current_cred();
> >
> > retval = -EPERM;
> > - if (!ns_capable(old->user_ns, CAP_SETGID)) {
> > + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) {
> > if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
> > !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
> > goto error;
> > @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> > new->sgid = ksgid;
> > new->fsgid = new->egid;
> >
> > + retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
> > + if (retval < 0)
> > + goto error;
> > +
> > return commit_creds(new);
> >
> > error:
> > @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid)
> >
> > if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
> > gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
> > - ns_capable(old->user_ns, CAP_SETGID)) {
> > + ns_capable_setid(old->user_ns, CAP_SETGID)) {
> > if (!gid_eq(kgid, old->fsgid)) {
> > new->fsgid = kgid;
> > - goto change_okay;
> > + if (security_task_fix_setgid(new,
> > + old,
> > + LSM_SETID_FS) == 0)
> > + goto change_okay;
> > }
> > }
> >
> > diff --git a/security/security.c b/security/security.c
> > index b6bff646d373..4264a1e77ce8 100644
> > --- a/security/security.c
> > +++ b/security/security.c
> > @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
> > return call_int_hook(task_fix_setuid, 0, new, old, flags);
> > }
> >
> > +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> > + int flags)
> > +{
> > + return call_int_hook(task_fix_setgid, 0, new, old, flags);
> > +}
> > +
> > int security_task_setpgid(struct task_struct *p, pid_t pgid)
> > {
> > return call_int_hook(task_setpgid, 0, p, pgid);
> > --
> > 2.21.0.rc0.258.g878e2cd30e-goog
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] LSM: SafeSetID: gate setgid transitions
2019-02-19 17:00 ` Micah Morton
@ 2019-02-19 18:20 ` Serge E. Hallyn
0 siblings, 0 replies; 4+ messages in thread
From: Serge E. Hallyn @ 2019-02-19 18:20 UTC (permalink / raw)
To: Micah Morton
Cc: Serge E. Hallyn, James Morris, Kees Cook, Casey Schaufler,
Stephen Smalley, linux-security-module
On Tue, Feb 19, 2019 at 09:00:13AM -0800, Micah Morton wrote:
> On Sat, Feb 16, 2019 at 8:43 AM Serge E. Hallyn <serge@hallyn.com> wrote:
> >
> > On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote:
> > > From: Micah Morton <mortonm@chromium.org>
> > >
> > > This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the
> > > existing 'task_fix_setuid' LSM hook, and calls this new hook from the
> > > setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to
> > > govern setgid transitions in addition to setuid transitions. This change
> > > also makes sure the setgid functions in kernel/sys.c call
> > > security_capable_setid rather than the ordinary security_capable
> >
> > Sorry, where security_capable_setid this defined? I assume it was in a recent
> > patchset, but google and grep are failing me.
>
> It was defined in commit 40852275a94afb3e836be9248399e036982d1a79 on
> the origin/next-general branch of
> git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git.
Thanks.
> > > function, so that the security_capable hook in the SafeSetID LSM knows
> > > it is being invoked from a setid function.
> > >
> > > Signed-off-by: Micah Morton <mortonm@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
> > > ---
> > > Tested with slight mod to test in tools/testing/selftests/safesetid for
> > > testing setgid as well as setuid.
> > >
> > > include/linux/lsm_hooks.h | 12 ++++++++++++
> > > include/linux/security.h | 10 ++++++++++
> > > kernel/sys.c | 27 +++++++++++++++++++++------
> > > security/security.c | 6 ++++++
> > > 4 files changed, 49 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > > index 22fc786d723a..f252ed3e95ef 100644
> > > --- a/include/linux/lsm_hooks.h
> > > +++ b/include/linux/lsm_hooks.h
> > > @@ -603,6 +603,15 @@
> > > * @old is the set of credentials that are being replaces
> > > * @flags contains one of the LSM_SETID_* values.
> > > * Return 0 on success.
> > > + * @task_fix_setgid:
> > > + * Update the module's state after setting one or more of the group
> > > + * identity attributes of the current process. The @flags parameter
> > > + * indicates which of the set*gid system calls invoked this hook.
> > > + * @new is the set of credentials that will be installed. Modifications
> > > + * should be made to this rather than to @current->cred.
> > > + * @old is the set of credentials that are being replaced
> > > + * @flags contains one of the LSM_SETID_* values.
> > > + * Return 0 on success.
> > > * @task_setpgid:
> > > * Check permission before setting the process group identifier of the
> > > * process @p to @pgid.
> > > @@ -1596,6 +1605,8 @@ union security_list_options {
> > > enum kernel_read_file_id id);
> > > int (*task_fix_setuid)(struct cred *new, const struct cred *old,
> > > int flags);
> > > + int (*task_fix_setgid)(struct cred *new, const struct cred *old,
> > > + int flags);
> > > int (*task_setpgid)(struct task_struct *p, pid_t pgid);
> > > int (*task_getpgid)(struct task_struct *p);
> > > int (*task_getsid)(struct task_struct *p);
> > > @@ -1887,6 +1898,7 @@ struct security_hook_heads {
> > > struct hlist_head kernel_post_read_file;
> > > struct hlist_head kernel_module_request;
> > > struct hlist_head task_fix_setuid;
> > > + struct hlist_head task_fix_setgid;
> > > struct hlist_head task_setpgid;
> > > struct hlist_head task_getpgid;
> > > struct hlist_head task_getsid;
> > > diff --git a/include/linux/security.h b/include/linux/security.h
> > > index 13537a49ae97..f3d095e8dfc1 100644
> > > --- a/include/linux/security.h
> > > +++ b/include/linux/security.h
> > > @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr);
> > > extern int cap_mmap_file(struct file *file, unsigned long reqprot,
> > > unsigned long prot, unsigned long flags);
> > > extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
> > > +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags);
> > > extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> > > unsigned long arg4, unsigned long arg5);
> > > extern int cap_task_setscheduler(struct task_struct *p);
> > > @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
> > > enum kernel_read_file_id id);
> > > int security_task_fix_setuid(struct cred *new, const struct cred *old,
> > > int flags);
> > > +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> > > + int flags);
> > > int security_task_setpgid(struct task_struct *p, pid_t pgid);
> > > int security_task_getpgid(struct task_struct *p);
> > > int security_task_getsid(struct task_struct *p);
> > > @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new,
> > > return cap_task_fix_setuid(new, old, flags);
> > > }
> > >
> > > +static inline int security_task_fix_setgid(struct cred *new,
> > > + const struct cred *old,
> > > + int flags)
> > > +{
> > > + return cap_task_fix_setgid(new, old, flags);
> > > +}
> > > +
> > > static inline int security_task_setpgid(struct task_struct *p, pid_t pgid)
> > > {
> > > return 0;
> > > diff --git a/kernel/sys.c b/kernel/sys.c
> > > index c5f875048aef..76f1c46ac66f 100644
> > > --- a/kernel/sys.c
> > > +++ b/kernel/sys.c
> > > @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > > if (rgid != (gid_t) -1) {
> > > if (gid_eq(old->gid, krgid) ||
> > > gid_eq(old->egid, krgid) ||
> > > - ns_capable(old->user_ns, CAP_SETGID))
> > > + ns_capable_setid(old->user_ns, CAP_SETGID))
> > > new->gid = krgid;
> > > else
> > > goto error;
> > > @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > > if (gid_eq(old->gid, kegid) ||
> > > gid_eq(old->egid, kegid) ||
> > > gid_eq(old->sgid, kegid) ||
> > > - ns_capable(old->user_ns, CAP_SETGID))
> > > + ns_capable_setid(old->user_ns, CAP_SETGID))
> > > new->egid = kegid;
> > > else
> > > goto error;
> > > @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid)
> > > new->sgid = new->egid;
> > > new->fsgid = new->egid;
> > >
> > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
> > > + if (retval < 0)
> > > + goto error;
> > > +
> > > return commit_creds(new);
> > >
> > > error:
> > > @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid)
> > > old = current_cred();
> > >
> > > retval = -EPERM;
> > > - if (ns_capable(old->user_ns, CAP_SETGID))
> > > + if (ns_capable_setid(old->user_ns, CAP_SETGID))
> > > new->gid = new->egid = new->sgid = new->fsgid = kgid;
> > > else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
> > > new->egid = new->fsgid = kgid;
> > > else
> > > goto error;
> > >
> > > + retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
> > > + if (retval < 0)
> > > + goto error;
> > > +
> > > return commit_creds(new);
> > >
> > > error:
> > > @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> > > old = current_cred();
> > >
> > > retval = -EPERM;
> > > - if (!ns_capable(old->user_ns, CAP_SETGID)) {
> > > + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) {
> > > if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
> > > !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
> > > goto error;
> > > @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
> > > new->sgid = ksgid;
> > > new->fsgid = new->egid;
> > >
> > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
> > > + if (retval < 0)
> > > + goto error;
> > > +
> > > return commit_creds(new);
> > >
> > > error:
> > > @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid)
> > >
> > > if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
> > > gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
> > > - ns_capable(old->user_ns, CAP_SETGID)) {
> > > + ns_capable_setid(old->user_ns, CAP_SETGID)) {
> > > if (!gid_eq(kgid, old->fsgid)) {
> > > new->fsgid = kgid;
> > > - goto change_okay;
> > > + if (security_task_fix_setgid(new,
> > > + old,
> > > + LSM_SETID_FS) == 0)
> > > + goto change_okay;
> > > }
> > > }
> > >
> > > diff --git a/security/security.c b/security/security.c
> > > index b6bff646d373..4264a1e77ce8 100644
> > > --- a/security/security.c
> > > +++ b/security/security.c
> > > @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
> > > return call_int_hook(task_fix_setuid, 0, new, old, flags);
> > > }
> > >
> > > +int security_task_fix_setgid(struct cred *new, const struct cred *old,
> > > + int flags)
> > > +{
> > > + return call_int_hook(task_fix_setgid, 0, new, old, flags);
> > > +}
> > > +
> > > int security_task_setpgid(struct task_struct *p, pid_t pgid)
> > > {
> > > return call_int_hook(task_setpgid, 0, p, pgid);
> > > --
> > > 2.21.0.rc0.258.g878e2cd30e-goog
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-02-19 18:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-02-15 22:22 [PATCH 1/2] LSM: SafeSetID: gate setgid transitions mortonm
2019-02-16 16:43 ` Serge E. Hallyn
2019-02-19 17:00 ` Micah Morton
2019-02-19 18:20 ` Serge E. Hallyn
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