Add lsm_name_to_attr(), which translates a text string to a
LSM_ATTR value if one is available.
Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
the trailing attribute value.
All are used in module specific components of LSM system calls.
Signed-off-by: Casey Schaufler <[email protected]>
Reviewed-by: Serge Hallyn <[email protected]>
---
include/linux/security.h | 14 +++++++++++++
security/lsm_syscalls.c | 24 ++++++++++++++++++++++
security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 82 insertions(+)
diff --git a/include/linux/security.h b/include/linux/security.h
index 475d0abfebda..75ac91223c2d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -32,6 +32,7 @@
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/sockptr.h>
+#include <uapi/linux/lsm.h>
struct linux_binprm;
struct cred;
@@ -263,6 +264,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb);
/* prototypes */
extern int security_init(void);
extern int early_security_init(void);
+extern u64 lsm_name_to_attr(const char *name);
/* Security operations */
int security_binder_set_context_mgr(const struct cred *mgr);
@@ -488,6 +490,8 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
int security_locked_down(enum lockdown_reason what);
+int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags);
#else /* CONFIG_SECURITY */
static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
@@ -505,6 +509,11 @@ static inline int unregister_blocking_lsm_notifier(struct notifier_block *nb)
return 0;
}
+static inline u64 lsm_name_to_attr(const char *name)
+{
+ return LSM_ATTR_UNDEF;
+}
+
static inline void security_free_mnt_opts(void **mnt_opts)
{
}
@@ -1408,6 +1417,11 @@ static inline int security_locked_down(enum lockdown_reason what)
{
return 0;
}
+static inline int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_SECURITY */
#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index f03f2d17ab49..bc22f05e2d8c 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -17,6 +17,30 @@
#include <linux/lsm_hooks.h>
#include <uapi/linux/lsm.h>
+/**
+ * lsm_name_to_attr - map an LSM attribute name to its ID
+ * @name: name of the attribute
+ *
+ * Returns the LSM attribute value associated with @name, or 0 if
+ * there is no mapping.
+ */
+u64 lsm_name_to_attr(const char *name)
+{
+ if (!strcmp(name, "current"))
+ return LSM_ATTR_CURRENT;
+ if (!strcmp(name, "exec"))
+ return LSM_ATTR_EXEC;
+ if (!strcmp(name, "fscreate"))
+ return LSM_ATTR_FSCREATE;
+ if (!strcmp(name, "keycreate"))
+ return LSM_ATTR_KEYCREATE;
+ if (!strcmp(name, "prev"))
+ return LSM_ATTR_PREV;
+ if (!strcmp(name, "sockcreate"))
+ return LSM_ATTR_SOCKCREATE;
+ return LSM_ATTR_UNDEF;
+}
+
/**
* sys_lsm_set_self_attr - Set current task's security module attribute
* @attr: which attribute to set
diff --git a/security/security.c b/security/security.c
index 199db23581f1..72ad7197b2c9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -770,6 +770,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
return 0;
}
+/**
+ * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
+ * @ctx: an LSM context to be filled
+ * @context: the new context value
+ * @context_size: the size of the new context value
+ * @id: LSM id
+ * @flags: LSM defined flags
+ *
+ * Fill all of the fields in a user space lsm_ctx structure.
+ * Caller is assumed to have verified that @ctx has enough space
+ * for @context.
+ *
+ * The total length is padded to a multiple of 64 bits to
+ * accomodate possible alignment issues.
+ *
+ * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
+ * if memory can't be allocated.
+ */
+int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
+ size_t context_size, u64 id, u64 flags)
+{
+ struct lsm_ctx *lctx;
+ size_t locallen = struct_size(lctx, ctx, context_size);
+ int rc = 0;
+
+ lctx = kzalloc(locallen, GFP_KERNEL);
+ if (lctx == NULL)
+ return -ENOMEM;
+
+ lctx->id = id;
+ lctx->flags = flags;
+ lctx->ctx_len = context_size;
+ lctx->len = locallen;
+
+ memcpy(lctx->ctx, context, context_size);
+
+ if (copy_to_user(ctx, lctx, locallen))
+ rc = -EFAULT;
+
+ kfree(lctx);
+
+ return rc;
+}
+
/*
* The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
* can be accessed with:
--
2.40.1
On Jun 29, 2023 Casey Schaufler <[email protected]> wrote:
>
> Add lsm_name_to_attr(), which translates a text string to a
> LSM_ATTR value if one is available.
>
> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
> the trailing attribute value.
>
> All are used in module specific components of LSM system calls.
>
> Signed-off-by: Casey Schaufler <[email protected]>
> Reviewed-by: Serge Hallyn <[email protected]>
> ---
> include/linux/security.h | 14 +++++++++++++
> security/lsm_syscalls.c | 24 ++++++++++++++++++++++
> security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 82 insertions(+)
...
> diff --git a/security/security.c b/security/security.c
> index 199db23581f1..72ad7197b2c9 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -770,6 +770,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
> return 0;
> }
>
> +/**
> + * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
> + * @ctx: an LSM context to be filled
> + * @context: the new context value
> + * @context_size: the size of the new context value
> + * @id: LSM id
> + * @flags: LSM defined flags
> + *
> + * Fill all of the fields in a user space lsm_ctx structure.
> + * Caller is assumed to have verified that @ctx has enough space
> + * for @context.
> + *
> + * The total length is padded to a multiple of 64 bits to
> + * accomodate possible alignment issues.
We should drop the sentence above now that alignment is the caller's
responsibility, but since that was largely my fault I can fix this up
during the merge assuming you're okay with that Casey.
> + * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
> + * if memory can't be allocated.
> + */
> +int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
> + size_t context_size, u64 id, u64 flags)
> +{
> + struct lsm_ctx *lctx;
> + size_t locallen = struct_size(lctx, ctx, context_size);
> + int rc = 0;
> +
> + lctx = kzalloc(locallen, GFP_KERNEL);
> + if (lctx == NULL)
> + return -ENOMEM;
> +
> + lctx->id = id;
> + lctx->flags = flags;
> + lctx->ctx_len = context_size;
> + lctx->len = locallen;
> +
> + memcpy(lctx->ctx, context, context_size);
> +
> + if (copy_to_user(ctx, lctx, locallen))
> + rc = -EFAULT;
> +
> + kfree(lctx);
> +
> + return rc;
> +}
> +
> /*
> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
> * can be accessed with:
> --
> 2.40.1
--
paul-moore.com
On 6/29/2023 7:14 PM, Paul Moore wrote:
> On Jun 29, 2023 Casey Schaufler <[email protected]> wrote:
>> Add lsm_name_to_attr(), which translates a text string to a
>> LSM_ATTR value if one is available.
>>
>> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
>> the trailing attribute value.
>>
>> All are used in module specific components of LSM system calls.
>>
>> Signed-off-by: Casey Schaufler <[email protected]>
>> Reviewed-by: Serge Hallyn <[email protected]>
>> ---
>> include/linux/security.h | 14 +++++++++++++
>> security/lsm_syscalls.c | 24 ++++++++++++++++++++++
>> security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 82 insertions(+)
> ..
>
>> diff --git a/security/security.c b/security/security.c
>> index 199db23581f1..72ad7197b2c9 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -770,6 +770,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
>> return 0;
>> }
>>
>> +/**
>> + * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
>> + * @ctx: an LSM context to be filled
>> + * @context: the new context value
>> + * @context_size: the size of the new context value
>> + * @id: LSM id
>> + * @flags: LSM defined flags
>> + *
>> + * Fill all of the fields in a user space lsm_ctx structure.
>> + * Caller is assumed to have verified that @ctx has enough space
>> + * for @context.
>> + *
>> + * The total length is padded to a multiple of 64 bits to
>> + * accomodate possible alignment issues.
> We should drop the sentence above now that alignment is the caller's
> responsibility, but since that was largely my fault I can fix this up
> during the merge assuming you're okay with that Casey.
I have to fix the error in patch 8/11 anyway. I can fix this, too.
>
>> + * Returns 0 on success, -EFAULT on a copyout error, -ENOMEM
>> + * if memory can't be allocated.
>> + */
>> +int lsm_fill_user_ctx(struct lsm_ctx __user *ctx, void *context,
>> + size_t context_size, u64 id, u64 flags)
>> +{
>> + struct lsm_ctx *lctx;
>> + size_t locallen = struct_size(lctx, ctx, context_size);
>> + int rc = 0;
>> +
>> + lctx = kzalloc(locallen, GFP_KERNEL);
>> + if (lctx == NULL)
>> + return -ENOMEM;
>> +
>> + lctx->id = id;
>> + lctx->flags = flags;
>> + lctx->ctx_len = context_size;
>> + lctx->len = locallen;
>> +
>> + memcpy(lctx->ctx, context, context_size);
>> +
>> + if (copy_to_user(ctx, lctx, locallen))
>> + rc = -EFAULT;
>> +
>> + kfree(lctx);
>> +
>> + return rc;
>> +}
>> +
>> /*
>> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
>> * can be accessed with:
>> --
>> 2.40.1
> --
> paul-moore.com
On Fri, Jun 30, 2023 at 1:11 PM Casey Schaufler <[email protected]> wrote:
>
> On 6/29/2023 7:14 PM, Paul Moore wrote:
> > On Jun 29, 2023 Casey Schaufler <[email protected]> wrote:
> >> Add lsm_name_to_attr(), which translates a text string to a
> >> LSM_ATTR value if one is available.
> >>
> >> Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including
> >> the trailing attribute value.
> >>
> >> All are used in module specific components of LSM system calls.
> >>
> >> Signed-off-by: Casey Schaufler <[email protected]>
> >> Reviewed-by: Serge Hallyn <[email protected]>
> >> ---
> >> include/linux/security.h | 14 +++++++++++++
> >> security/lsm_syscalls.c | 24 ++++++++++++++++++++++
> >> security/security.c | 44 ++++++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 82 insertions(+)
> > ..
> >
> >> diff --git a/security/security.c b/security/security.c
> >> index 199db23581f1..72ad7197b2c9 100644
> >> --- a/security/security.c
> >> +++ b/security/security.c
> >> @@ -770,6 +770,50 @@ static int lsm_superblock_alloc(struct super_block *sb)
> >> return 0;
> >> }
> >>
> >> +/**
> >> + * lsm_fill_user_ctx - Fill a user space lsm_ctx structure
> >> + * @ctx: an LSM context to be filled
> >> + * @context: the new context value
> >> + * @context_size: the size of the new context value
> >> + * @id: LSM id
> >> + * @flags: LSM defined flags
> >> + *
> >> + * Fill all of the fields in a user space lsm_ctx structure.
> >> + * Caller is assumed to have verified that @ctx has enough space
> >> + * for @context.
> >> + *
> >> + * The total length is padded to a multiple of 64 bits to
> >> + * accomodate possible alignment issues.
> > We should drop the sentence above now that alignment is the caller's
> > responsibility, but since that was largely my fault I can fix this up
> > during the merge assuming you're okay with that Casey.
>
> I have to fix the error in patch 8/11 anyway. I can fix this, too.
Great, thanks.
--
paul-moore.com