[PATCH v2 3/6] LSM: Use lsm_context in security_inode_getsecctx
Casey Schaufler
casey at schaufler-ca.com
Mon Oct 14 15:14:47 UTC 2024
Change the security_inode_getsecctx() interface to fill a lsm_context
structure instead of data and length pointers. This provides
the information about which LSM created the context so that
security_release_secctx() can use the correct hook.
Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
Cc: linux-nfs at vger.kernel.org
---
fs/nfsd/nfs4xdr.c | 26 ++++++++++----------------
include/linux/lsm_hook_defs.h | 4 ++--
include/linux/security.h | 5 +++--
security/security.c | 12 ++++++------
security/selinux/hooks.c | 10 ++++++----
security/smack/smack_lsm.c | 7 ++++---
6 files changed, 31 insertions(+), 33 deletions(-)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 537ad363d70a..93faa238b979 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2827,11 +2827,11 @@ static __be32 nfsd4_encode_nfsace4(struct xdr_stream *xdr, struct svc_rqst *rqst
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
static inline __be32
nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
- void *context, int len)
+ const struct lsm_context *context)
{
__be32 *p;
- p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
+ p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
if (!p)
return nfserr_resource;
@@ -2841,13 +2841,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
*/
*p++ = cpu_to_be32(0); /* lfs */
*p++ = cpu_to_be32(0); /* pi */
- p = xdr_encode_opaque(p, context, len);
+ p = xdr_encode_opaque(p, context->context, context->len);
return 0;
}
#else
static inline __be32
nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
- void *context, int len)
+ struct lsm_context *context)
{ return 0; }
#endif
@@ -2930,8 +2930,7 @@ struct nfsd4_fattr_args {
struct nfs4_acl *acl;
u64 size;
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
- void *context;
- int contextlen;
+ struct lsm_context context;
#endif
u32 rdattr_err;
bool contextsupport;
@@ -3386,8 +3385,7 @@ static __be32 nfsd4_encode_fattr4_suppattr_exclcreat(struct xdr_stream *xdr,
static __be32 nfsd4_encode_fattr4_sec_label(struct xdr_stream *xdr,
const struct nfsd4_fattr_args *args)
{
- return nfsd4_encode_security_label(xdr, args->rqstp,
- args->context, args->contextlen);
+ return nfsd4_encode_security_label(xdr, args->rqstp, &args->context);
}
#endif
@@ -3538,7 +3536,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
args.ignore_crossmnt = (ignore_crossmnt != 0);
args.acl = NULL;
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
- args.context = NULL;
+ args.context.context = NULL;
#endif
/*
@@ -3616,7 +3614,7 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
attrmask[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
err = security_inode_getsecctx(d_inode(dentry),
- &args.context, &args.contextlen);
+ &args.context);
else
err = -EOPNOTSUPP;
args.contextsupport = (err == 0);
@@ -3653,12 +3651,8 @@ nfsd4_encode_fattr4(struct svc_rqst *rqstp, struct xdr_stream *xdr,
out:
#ifdef CONFIG_NFSD_V4_SECURITY_LABEL
- if (args.context) {
- struct lsm_context scaff; /* scaffolding */
-
- lsmcontext_init(&scaff, args.context, args.contextlen, 0);
- security_release_secctx(&scaff);
- }
+ if (args.context.context)
+ security_release_secctx(&args.context);
#endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
kfree(args.acl);
if (tempfh) {
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 01e5a8e09bba..69e1076448c6 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -303,8 +303,8 @@ LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp)
LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode)
LSM_HOOK(int, 0, inode_notifysecctx, struct inode *inode, void *ctx, u32 ctxlen)
LSM_HOOK(int, 0, inode_setsecctx, struct dentry *dentry, void *ctx, u32 ctxlen)
-LSM_HOOK(int, -EOPNOTSUPP, inode_getsecctx, struct inode *inode, void **ctx,
- u32 *ctxlen)
+LSM_HOOK(int, -EOPNOTSUPP, inode_getsecctx, struct inode *inode,
+ struct lsm_context *cp)
#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
LSM_HOOK(int, 0, post_notification, const struct cred *w_cred,
diff --git a/include/linux/security.h b/include/linux/security.h
index 64e8b18e6ea5..7d0adc1833ab 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -591,7 +591,7 @@ 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);
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp);
int security_locked_down(enum lockdown_reason what);
int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
void *val, size_t val_len, u64 id, u64 flags);
@@ -1591,7 +1591,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
{
return -EOPNOTSUPP;
}
-static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static inline int security_inode_getsecctx(struct inode *inode,
+ struct lsm_context *cp)
{
return -EOPNOTSUPP;
}
diff --git a/security/security.c b/security/security.c
index 914d8c8beea7..4ca3c9e28b6f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -4431,17 +4431,17 @@ EXPORT_SYMBOL(security_inode_setsecctx);
/**
* security_inode_getsecctx() - Get the security label of an inode
* @inode: inode
- * @ctx: secctx
- * @ctxlen: length of secctx
+ * @cp: security context
*
- * On success, returns 0 and fills out @ctx and @ctxlen with the security
- * context for the given @inode.
+ * On success, returns 0 and fills out @cp with the security context
+ * for the given @inode.
*
* Return: Returns 0 on success, error on failure.
*/
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
{
- return call_int_hook(inode_getsecctx, inode, ctx, ctxlen);
+ memset(cp, 0, sizeof(*cp));
+ return call_int_hook(inode_getsecctx, inode, cp);
}
EXPORT_SYMBOL(security_inode_getsecctx);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 692735eb04aa..ce5e45abd8d3 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6678,14 +6678,16 @@ static int selinux_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
ctx, ctxlen, 0, NULL);
}
-static int selinux_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static int selinux_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
{
- int len = 0;
+ int len;
len = selinux_inode_getsecurity(&nop_mnt_idmap, inode,
- XATTR_SELINUX_SUFFIX, ctx, true);
+ XATTR_SELINUX_SUFFIX,
+ (void **)&cp->context, true);
if (len < 0)
return len;
- *ctxlen = len;
+ cp->len = len;
+ cp->id = LSM_ID_SELINUX;
return 0;
}
#ifdef CONFIG_KEYS
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d52163d3dd64..c9ec4d93fb13 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4899,12 +4899,13 @@ static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
ctx, ctxlen, 0, NULL);
}
-static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static int smack_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
{
struct smack_known *skp = smk_of_inode(inode);
- *ctx = skp->smk_known;
- *ctxlen = strlen(skp->smk_known);
+ cp->context = skp->smk_known;
+ cp->len = strlen(skp->smk_known);
+ cp->id = LSM_ID_SMACK;
return 0;
}
--
2.46.0
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