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Message-ID: <20240917235202.32578-4-casey@schaufler-ca.com>
Date: Tue, 17 Sep 2024 16:52:00 -0700
From: Casey Schaufler <casey@...aufler-ca.com>
To: casey@...aufler-ca.com,
paul@...l-moore.com,
linux-security-module@...r.kernel.org
Cc: jmorris@...ei.org,
serge@...lyn.com,
keescook@...omium.org,
john.johansen@...onical.com,
penguin-kernel@...ove.sakura.ne.jp,
stephen.smalley.work@...il.com,
linux-kernel@...r.kernel.org,
selinux@...r.kernel.org,
mic@...ikod.net,
ceph-devel@...r.kernel.org,
linux-nfs@...r.kernel.org
Subject: [PATCH 3/5] LSM: lsm_context in security_dentry_init_security
Replace the (secctx,seclen) pointer pair with a single lsm_context
pointer to allow return of the LSM identifier along with the context
and context length. This allows security_release_secctx() to know how
to release the context. Callers have been modified to use or save the
returned data from the new structure.
Special care is taken in the NFS code, which uses the same data structure
for its own copied labels as it does for the data which comes from
security_dentry_init_security(). In the case of copied labels the data
has to be freed, not released.
The scaffolding funtion lsmcontext_init() is no longer needed and is
removed.
Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
Cc: ceph-devel@...r.kernel.org
Cc: linux-nfs@...r.kernel.org
---
fs/ceph/super.h | 3 +--
fs/ceph/xattr.c | 16 ++++++----------
fs/fuse/dir.c | 35 ++++++++++++++++++-----------------
fs/nfs/dir.c | 2 +-
fs/nfs/inode.c | 17 ++++++++++-------
fs/nfs/internal.h | 8 +++++---
fs/nfs/nfs4proc.c | 22 +++++++++-------------
fs/nfs/nfs4xdr.c | 22 ++++++++++++----------
include/linux/lsm_hook_defs.h | 2 +-
include/linux/nfs4.h | 8 ++++----
include/linux/nfs_fs.h | 2 +-
include/linux/security.h | 26 +++-----------------------
security/security.c | 9 ++++-----
security/selinux/hooks.c | 9 +++++----
14 files changed, 80 insertions(+), 101 deletions(-)
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 6e817bf1337c..0a6f61e247a7 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1135,8 +1135,7 @@ struct ceph_acl_sec_ctx {
void *acl;
#endif
#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
- void *sec_ctx;
- u32 sec_ctxlen;
+ struct lsm_context lsmctx;
#endif
#ifdef CONFIG_FS_ENCRYPTION
struct ceph_fscrypt_auth *fscrypt_auth;
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index f7996770cc2c..0b9e1f385d31 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1383,8 +1383,7 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
int err;
err = security_dentry_init_security(dentry, mode, &dentry->d_name,
- &name, &as_ctx->sec_ctx,
- &as_ctx->sec_ctxlen);
+ &name, &as_ctx->lsmctx);
if (err < 0) {
WARN_ON_ONCE(err != -EOPNOTSUPP);
err = 0; /* do nothing */
@@ -1409,7 +1408,7 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
*/
name_len = strlen(name);
err = ceph_pagelist_reserve(pagelist,
- 4 * 2 + name_len + as_ctx->sec_ctxlen);
+ 4 * 2 + name_len + as_ctx->lsmctx.len);
if (err)
goto out;
@@ -1432,8 +1431,9 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
ceph_pagelist_encode_32(pagelist, name_len);
ceph_pagelist_append(pagelist, name, name_len);
- ceph_pagelist_encode_32(pagelist, as_ctx->sec_ctxlen);
- ceph_pagelist_append(pagelist, as_ctx->sec_ctx, as_ctx->sec_ctxlen);
+ ceph_pagelist_encode_32(pagelist, as_ctx->lsmctx.len);
+ ceph_pagelist_append(pagelist, as_ctx->lsmctx.context,
+ as_ctx->lsmctx.len);
err = 0;
out:
@@ -1446,16 +1446,12 @@ int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
{
-#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
- struct lsm_context scaff; /* scaffolding */
-#endif
#ifdef CONFIG_CEPH_FS_POSIX_ACL
posix_acl_release(as_ctx->acl);
posix_acl_release(as_ctx->default_acl);
#endif
#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
- lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
- security_release_secctx(&scaff);
+ security_release_secctx(&as_ctx->lsmctx);
#endif
#ifdef CONFIG_FS_ENCRYPTION
kfree(as_ctx->fscrypt_auth);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 2b0d4781f394..6f95cd92e089 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -466,29 +466,29 @@ static int get_security_context(struct dentry *entry, umode_t mode,
{
struct fuse_secctx *fctx;
struct fuse_secctx_header *header;
- void *ctx = NULL, *ptr;
- u32 ctxlen, total_len = sizeof(*header);
+ struct lsm_context lsmctx = { };
+ void *ptr;
+ u32 total_len = sizeof(*header);
int err, nr_ctx = 0;
- const char *name;
+ const char *name = NULL;
size_t namelen;
err = security_dentry_init_security(entry, mode, &entry->d_name,
- &name, &ctx, &ctxlen);
- if (err) {
- if (err != -EOPNOTSUPP)
- goto out_err;
- /* No LSM is supporting this security hook. Ignore error */
- ctxlen = 0;
- ctx = NULL;
- }
+ &name, &lsmctx);
+
+ /* If no LSM is supporting this security hook ignore error */
+ if (err && err != -EOPNOTSUPP)
+ goto out_err;
- if (ctxlen) {
+ if (lsmctx.len) {
nr_ctx = 1;
namelen = strlen(name) + 1;
err = -EIO;
- if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
+ if (WARN_ON(namelen > XATTR_NAME_MAX + 1 ||
+ lsmctx.len > S32_MAX))
goto out_err;
- total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
+ total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen +
+ lsmctx.len);
}
err = -ENOMEM;
@@ -501,19 +501,20 @@ static int get_security_context(struct dentry *entry, umode_t mode,
ptr += sizeof(*header);
if (nr_ctx) {
fctx = ptr;
- fctx->size = ctxlen;
+ fctx->size = lsmctx.len;
ptr += sizeof(*fctx);
strcpy(ptr, name);
ptr += namelen;
- memcpy(ptr, ctx, ctxlen);
+ memcpy(ptr, lsmctx.context, lsmctx.len);
}
ext->size = total_len;
ext->value = header;
err = 0;
out_err:
- kfree(ctx);
+ if (nr_ctx)
+ security_release_secctx(&lsmctx);
return err;
}
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 4cb97ef41350..83e420bbcba6 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -809,7 +809,7 @@ static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc,
int ret;
if (entry->fattr->label)
- entry->fattr->label->len = NFS4_MAXLABELLEN;
+ entry->fattr->label->lsmctx.len = NFS4_MAXLABELLEN;
ret = xdr_decode(desc, entry, stream);
if (ret || !desc->plus)
return ret;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index b4914a11c3c2..056ddc876cb5 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -358,14 +358,15 @@ void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
return;
if ((fattr->valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL) && inode->i_security) {
- error = security_inode_notifysecctx(inode, fattr->label->label,
- fattr->label->len);
+ error = security_inode_notifysecctx(inode,
+ fattr->label->lsmctx.context,
+ fattr->label->lsmctx.len);
if (error)
printk(KERN_ERR "%s() %s %d "
"security_inode_notifysecctx() %d\n",
__func__,
- (char *)fattr->label->label,
- fattr->label->len, error);
+ (char *)fattr->label->lsmctx.context,
+ fattr->label->lsmctx.len, error);
nfs_clear_label_invalid(inode);
}
}
@@ -381,12 +382,14 @@ struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
if (label == NULL)
return ERR_PTR(-ENOMEM);
- label->label = kzalloc(NFS4_MAXLABELLEN, flags);
- if (label->label == NULL) {
+ label->lsmctx.context = kzalloc(NFS4_MAXLABELLEN, flags);
+ if (label->lsmctx.context == NULL) {
kfree(label);
return ERR_PTR(-ENOMEM);
}
- label->len = NFS4_MAXLABELLEN;
+ label->lsmctx.len = NFS4_MAXLABELLEN;
+ /* Use an invalid LSM ID as this should never be "released". */
+ label->lsmctx.id = LSM_ID_UNDEF;
return label;
}
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 5902a9beca1f..93911f3133ab 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -353,13 +353,15 @@ nfs4_label_copy(struct nfs4_label *dst, struct nfs4_label *src)
if (!dst || !src)
return NULL;
- if (src->len > NFS4_MAXLABELLEN)
+ if (src->lsmctx.len > NFS4_MAXLABELLEN)
return NULL;
dst->lfs = src->lfs;
dst->pi = src->pi;
- dst->len = src->len;
- memcpy(dst->label, src->label, src->len);
+ /* Use an invalid LSM ID as lsmctx should never be "released" */
+ dst->lsmctx.id = LSM_ID_UNDEF;
+ dst->lsmctx.len = src->lsmctx.len;
+ memcpy(dst->lsmctx.context, src->lsmctx.context, src->lsmctx.len);
return dst;
}
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 18888588a642..293307042c20 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -124,12 +124,11 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
label->lfs = 0;
label->pi = 0;
- label->len = 0;
- label->label = NULL;
+ label->lsmctx.len = 0;
+ label->lsmctx.context = NULL;
err = security_dentry_init_security(dentry, sattr->ia_mode,
- &dentry->d_name, NULL,
- (void **)&label->label, &label->len);
+ &dentry->d_name, NULL, &label->lsmctx);
if (err == 0)
return label;
@@ -138,12 +137,8 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
static inline void
nfs4_label_release_security(struct nfs4_label *label)
{
- struct lsm_context scaff; /* scaffolding */
-
- if (label) {
- lsmcontext_init(&scaff, label->label, label->len, 0);
- security_release_secctx(&scaff);
- }
+ if (label)
+ security_release_secctx(&label->lsmctx);
}
static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
{
@@ -6246,7 +6241,7 @@ static int _nfs4_get_security_label(struct inode *inode, void *buf,
size_t buflen)
{
struct nfs_server *server = NFS_SERVER(inode);
- struct nfs4_label label = {0, 0, buflen, buf};
+ struct nfs4_label label = {0, 0, {buf, buflen, -1} };
u32 bitmask[3] = { 0, 0, FATTR4_WORD2_SECURITY_LABEL };
struct nfs_fattr fattr = {
@@ -6274,7 +6269,7 @@ static int _nfs4_get_security_label(struct inode *inode, void *buf,
return ret;
if (!(fattr.valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL))
return -ENOENT;
- return label.len;
+ return label.lsmctx.len;
}
static int nfs4_get_security_label(struct inode *inode, void *buf,
@@ -6351,7 +6346,8 @@ static int nfs4_do_set_security_label(struct inode *inode,
static int
nfs4_set_security_label(struct inode *inode, const void *buf, size_t buflen)
{
- struct nfs4_label ilabel = {0, 0, buflen, (char *)buf };
+ struct nfs4_label ilabel = {0, 0,
+ {(char *)buf, buflen, -1}};
struct nfs_fattr *fattr;
int status;
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 7704a4509676..db86b9cea716 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1162,7 +1162,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
}
if (label && (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL)) {
- len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
+ len += 4 + 4 + 4 + (XDR_QUADLEN(label->lsmctx.len) << 2);
bmval[2] |= FATTR4_WORD2_SECURITY_LABEL;
}
@@ -1194,8 +1194,9 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
if (label && (bmval[2] & FATTR4_WORD2_SECURITY_LABEL)) {
*p++ = cpu_to_be32(label->lfs);
*p++ = cpu_to_be32(label->pi);
- *p++ = cpu_to_be32(label->len);
- p = xdr_encode_opaque_fixed(p, label->label, label->len);
+ *p++ = cpu_to_be32(label->lsmctx.len);
+ p = xdr_encode_opaque_fixed(p, label->lsmctx.context,
+ label->lsmctx.len);
}
if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
@@ -4280,11 +4281,11 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap,
return -EIO;
bitmap[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
if (len < NFS4_MAXLABELLEN) {
- if (label && label->len) {
- if (label->len < len)
+ if (label && label->lsmctx.len) {
+ if (label->lsmctx.len < len)
return -ERANGE;
- memcpy(label->label, p, len);
- label->len = len;
+ memcpy(label->lsmctx.context, p, len);
+ label->lsmctx.len = len;
label->pi = pi;
label->lfs = lfs;
status = NFS_ATTR_FATTR_V4_SECURITY_LABEL;
@@ -4292,10 +4293,11 @@ static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap,
} else
printk(KERN_WARNING "%s: label too long (%u)!\n",
__func__, len);
- if (label && label->label)
+ if (label && label->lsmctx.context)
dprintk("%s: label=%.*s, len=%d, PI=%d, LFS=%d\n",
- __func__, label->len, (char *)label->label,
- label->len, label->pi, label->lfs);
+ __func__, label->lsmctx.len,
+ (char *)label->lsmctx.context,
+ label->lsmctx.len, label->pi, label->lfs);
}
return status;
}
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 8090952b989e..6b671f4ada03 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -83,7 +83,7 @@ LSM_HOOK(int, 0, move_mount, const struct path *from_path,
const struct path *to_path)
LSM_HOOK(int, -EOPNOTSUPP, dentry_init_security, struct dentry *dentry,
int mode, const struct qstr *name, const char **xattr_name,
- void **ctx, u32 *ctxlen)
+ struct lsm_context *cp)
LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
struct qstr *name, const struct cred *old, struct cred *new)
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index f9df88091c6d..002cf1bff00a 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -15,6 +15,7 @@
#include <linux/list.h>
#include <linux/uidgid.h>
+#include <linux/security.h>
#include <uapi/linux/nfs4.h>
#include <linux/sunrpc/msg_prot.h>
@@ -44,10 +45,9 @@ struct nfs4_acl {
#define NFS4_MAXLABELLEN 2048
struct nfs4_label {
- uint32_t lfs;
- uint32_t pi;
- u32 len;
- char *label;
+ uint32_t lfs;
+ uint32_t pi;
+ struct lsm_context lsmctx;
};
typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 039898d70954..47652d217d05 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -457,7 +457,7 @@ static inline void nfs4_label_free(struct nfs4_label *label)
{
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
if (label) {
- kfree(label->label);
+ kfree(label->lsmctx.context);
kfree(label);
}
#endif
diff --git a/include/linux/security.h b/include/linux/security.h
index 94bcb4c69a9c..c9c4845da3a6 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -225,25 +225,6 @@ struct lsm_context {
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
*/
@@ -397,8 +378,8 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
int security_move_mount(const struct path *from_path, const struct path *to_path);
int security_dentry_init_security(struct dentry *dentry, int mode,
const struct qstr *name,
- const char **xattr_name, void **ctx,
- u32 *ctxlen);
+ const char **xattr_name,
+ struct lsm_context *lsmcxt);
int security_dentry_create_files_as(struct dentry *dentry, int mode,
struct qstr *name,
const struct cred *old,
@@ -863,8 +844,7 @@ static inline int security_dentry_init_security(struct dentry *dentry,
int mode,
const struct qstr *name,
const char **xattr_name,
- void **ctx,
- u32 *ctxlen)
+ struct lsm_context *lsmcxt)
{
return -EOPNOTSUPP;
}
diff --git a/security/security.c b/security/security.c
index 5a739279ed49..020e7a89de16 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1631,8 +1631,7 @@ void security_inode_free(struct inode *inode)
* @mode: mode used to determine resource type
* @name: name of the last path component
* @xattr_name: name of the security/LSM xattr
- * @ctx: pointer to the resulting LSM context
- * @ctxlen: length of @ctx
+ * @lsmctx: pointer to the resulting LSM context
*
* Compute a context for a dentry as the inode is not yet available since NFSv4
* has no label backed by an EA anyway. It is important to note that
@@ -1642,11 +1641,11 @@ void security_inode_free(struct inode *inode)
*/
int security_dentry_init_security(struct dentry *dentry, int mode,
const struct qstr *name,
- const char **xattr_name, void **ctx,
- u32 *ctxlen)
+ const char **xattr_name,
+ struct lsm_context *lsmctx)
{
return call_int_hook(dentry_init_security, dentry, mode, name,
- xattr_name, ctx, ctxlen);
+ xattr_name, lsmctx);
}
EXPORT_SYMBOL(security_dentry_init_security);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 159837b4ee41..e56403659164 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2871,8 +2871,8 @@ static void selinux_inode_free_security(struct inode *inode)
static int selinux_dentry_init_security(struct dentry *dentry, int mode,
const struct qstr *name,
- const char **xattr_name, void **ctx,
- u32 *ctxlen)
+ const char **xattr_name,
+ struct lsm_context *cp)
{
u32 newsid;
int rc;
@@ -2887,8 +2887,9 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
if (xattr_name)
*xattr_name = XATTR_NAME_SELINUX;
- return security_sid_to_context(newsid, (char **)ctx,
- ctxlen);
+ cp->id = LSM_ID_SELINUX;
+ return security_sid_to_context(newsid, (char **)cp->context,
+ &cp->len);
}
static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,
--
2.46.0
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