diff options
| author | Casey Schaufler <casey@schaufler-ca.com> | 2024-10-23 14:21:54 -0700 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2024-12-04 10:46:26 -0500 |
| commit | 6fba89813ccf333d2bc4d5caea04cd5f3c39eb50 (patch) | |
| tree | b81fee3690bd96f7009b49f7dca8f4a33bc11f01 /include/linux/security.h | |
| parent | 40384c840ea1944d7c5a392e8975ed088ecf0b37 (diff) | |
| download | lwn-6fba89813ccf333d2bc4d5caea04cd5f3c39eb50.tar.gz lwn-6fba89813ccf333d2bc4d5caea04cd5f3c39eb50.zip | |
lsm: ensure the correct LSM context releaser
Add a new lsm_context data structure to hold all the information about a
"security context", including the string, its size and which LSM allocated
the string. The allocation information is necessary because LSMs have
different policies regarding the lifecycle of these strings. SELinux
allocates and destroys them on each use, whereas Smack provides a pointer
to an entry in a list that never goes away.
Update security_release_secctx() to use the lsm_context instead of a
(char *, len) pair. Change its callers to do likewise. The LSMs
supporting this hook have had comments added to remind the developer
that there is more work to be done.
The BPF security module provides all LSM hooks. While there has yet to
be a known instance of a BPF configuration that uses security contexts,
the possibility is real. In the existing implementation there is
potential for multiple frees in that case.
Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: linux-nfs@vger.kernel.org
Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'include/linux/security.h')
| -rw-r--r-- | include/linux/security.h | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/include/linux/security.h b/include/linux/security.h index cbdba435b798..68e56935716b 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -226,6 +226,37 @@ extern unsigned long dac_mmap_min_addr; #endif /* + * A "security context" is the text representation of + * the information used by LSMs. + * This structure contains the string, its length, and which LSM + * it is useful for. + */ +struct lsm_context { + char *context; /* Provided by the module */ + u32 len; + int id; /* Identifies the module */ +}; + +/** + * lsmcontext_init - initialize an lsmcontext structure. + * @cp: Pointer to the context to initialize + * @context: Initial context, or NULL + * @size: Size of context, or 0 + * @id: Which LSM provided the context + * + * Fill in the lsmcontext from the provided information. + * This is a scaffolding function that will be removed when + * lsm_context integration is complete. + */ +static inline void lsmcontext_init(struct lsm_context *cp, char *context, + u32 size, int id) +{ + cp->id = id; + cp->context = context; + cp->len = size; +} + +/* * Values used in the task_security_ops calls */ /* setuid or setgid, id0 == uid or gid */ @@ -556,7 +587,7 @@ int security_ismaclabel(const char *name); int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); int security_lsmprop_to_secctx(struct lsm_prop *prop, char **secdata, u32 *seclen); int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); -void security_release_secctx(char *secdata, u32 seclen); +void security_release_secctx(struct lsm_context *cp); void security_inode_invalidate_secctx(struct inode *inode); int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); @@ -1545,7 +1576,7 @@ static inline int security_secctx_to_secid(const char *secdata, return -EOPNOTSUPP; } -static inline void security_release_secctx(char *secdata, u32 seclen) +static inline void security_release_secctx(struct lsm_context *cp) { } |