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[213.175.37.10]) by smtp.gmail.com with ESMTPSA id n124sm2417691wmd.15.2019.01.30.03.43.12 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 30 Jan 2019 03:43:12 -0800 (PST) From: Ondrej Mosnacek To: selinux@vger.kernel.org, Paul Moore Cc: Stephen Smalley , linux-security-module@vger.kernel.org, Casey Schaufler , Greg Kroah-Hartman , Tejun Heo , linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, Ondrej Mosnacek Subject: [PATCH v3 2/5] kernfs: use simple_xattrs for security attributes Date: Wed, 30 Jan 2019 12:41:47 +0100 Message-Id: <20190130114150.27807-3-omosnace@redhat.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190130114150.27807-1-omosnace@redhat.com> References: <20190130114150.27807-1-omosnace@redhat.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Replace the special handling of security xattrs with simple_xattrs, as is already done for the trusted xattrs. This simplifies the code and allows LSMs to use more than just a single xattr to do their business. Signed-off-by: Ondrej Mosnacek --- fs/kernfs/dir.c | 7 ++- fs/kernfs/inode.c | 100 +++++++++++++++--------------------- fs/kernfs/kernfs-internal.h | 5 +- 3 files changed, 46 insertions(+), 66 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 4ca0b5c18192..ad7e3356bcc5 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -532,11 +532,10 @@ void kernfs_put(struct kernfs_node *kn) kfree_const(kn->name); if (kn->iattr) { - if (kn->iattr->ia_secdata) - security_release_secctx(kn->iattr->ia_secdata, - kn->iattr->ia_secdata_len); - simple_xattrs_free(&kn->iattr->xattrs); + simple_xattrs_free(&kn->iattr->xattrs_trusted); + simple_xattrs_free(&kn->iattr->xattrs_security); } + kfree(kn->iattr); spin_lock(&kernfs_idr_lock); idr_remove(&root->ino_idr, kn->id.ino); diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index 80cebcd94c90..f0e2cb4379c0 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -56,7 +56,8 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn) iattrs->ia_mtime = iattrs->ia_atime; iattrs->ia_ctime = iattrs->ia_atime; - simple_xattrs_init(&kn->iattr->xattrs); + simple_xattrs_init(&kn->iattr->xattrs_trusted); + simple_xattrs_init(&kn->iattr->xattrs_security); out_unlock: ret = kn->iattr; mutex_unlock(&iattr_mutex); @@ -135,33 +136,31 @@ out: return error; } -static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata, - u32 *secdata_len) -{ - void *old_secdata; - size_t old_secdata_len; - - old_secdata = attrs->ia_secdata; - old_secdata_len = attrs->ia_secdata_len; - - attrs->ia_secdata = *secdata; - attrs->ia_secdata_len = *secdata_len; - - *secdata = old_secdata; - *secdata_len = old_secdata_len; - return 0; -} - ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size) { struct kernfs_node *kn = kernfs_dentry_node(dentry); + struct inode *inode = d_inode(dentry); struct kernfs_iattrs *attrs; + ssize_t ret, length = 0; attrs = kernfs_iattrs(kn); if (!attrs) return -ENOMEM; - return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size); + ret = simple_xattr_list(inode, &attrs->xattrs_trusted, buf, size); + if (ret < 0) + return ret; + length += ret; + + buf += ret; + size -= ret; + + ret = simple_xattr_list(inode, &attrs->xattrs_security, buf, size); + if (ret < 0) + return ret; + length += ret; + + return length; } static inline void set_default_inode_attr(struct inode *inode, umode_t mode) @@ -186,15 +185,12 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode) struct kernfs_iattrs *attrs = kn->iattr; inode->i_mode = kn->mode; - if (attrs) { + if (attrs) /* * kernfs_node has non-default attributes get them from * persistent copy in kernfs_node. */ set_inode_attr(inode, &attrs->ia_iattr); - security_inode_notifysecctx(inode, attrs->ia_secdata, - attrs->ia_secdata_len); - } if (kernfs_type(kn) == KERNFS_DIR) set_nlink(inode, kn->dir.subdirs + 2); @@ -305,19 +301,29 @@ int kernfs_iop_permission(struct inode *inode, int mask) return generic_permission(inode, mask); } +static const struct xattr_handler kernfs_trusted_xattr_handler; +static const struct xattr_handler kernfs_security_xattr_handler; + static int kernfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, const char *suffix, void *value, size_t size) { - const char *name = xattr_full_name(handler, suffix); struct kernfs_node *kn = inode->i_private; struct kernfs_iattrs *attrs; + struct simple_xattrs *xattrs; attrs = kernfs_iattrs(kn); if (!attrs) return -ENOMEM; - return simple_xattr_get(&attrs->xattrs, name, value, size); + if (handler == &kernfs_trusted_xattr_handler) + xattrs = &attrs->xattrs_trusted; + else if (handler == &kernfs_security_xattr_handler) + xattrs = &attrs->xattrs_security; + else + return -EINVAL; + + return simple_xattr_get(xattrs, suffix, value, size); } static int kernfs_xattr_set(const struct xattr_handler *handler, @@ -325,15 +331,22 @@ static int kernfs_xattr_set(const struct xattr_handler *handler, const char *suffix, const void *value, size_t size, int flags) { - const char *name = xattr_full_name(handler, suffix); struct kernfs_node *kn = inode->i_private; struct kernfs_iattrs *attrs; + struct simple_xattrs *xattrs; attrs = kernfs_iattrs(kn); if (!attrs) return -ENOMEM; - return simple_xattr_set(&attrs->xattrs, name, value, size, flags); + if (handler == &kernfs_trusted_xattr_handler) + xattrs = &attrs->xattrs_trusted; + else if (handler == &kernfs_security_xattr_handler) + xattrs = &attrs->xattrs_security; + else + return -EINVAL; + + return simple_xattr_set(xattrs, suffix, value, size, flags); } static const struct xattr_handler kernfs_trusted_xattr_handler = { @@ -342,41 +355,10 @@ static const struct xattr_handler kernfs_trusted_xattr_handler = { .set = kernfs_xattr_set, }; -static int kernfs_security_xattr_set(const struct xattr_handler *handler, - struct dentry *unused, struct inode *inode, - const char *suffix, const void *value, - size_t size, int flags) -{ - struct kernfs_node *kn = inode->i_private; - struct kernfs_iattrs *attrs; - void *secdata; - u32 secdata_len = 0; - int error; - - attrs = kernfs_iattrs(kn); - if (!attrs) - return -ENOMEM; - - error = security_inode_setsecurity(inode, suffix, value, size, flags); - if (error) - return error; - error = security_inode_getsecctx(inode, &secdata, &secdata_len); - if (error) - return error; - - mutex_lock(&kernfs_mutex); - error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len); - mutex_unlock(&kernfs_mutex); - - if (secdata) - security_release_secctx(secdata, secdata_len); - return error; -} - static const struct xattr_handler kernfs_security_xattr_handler = { .prefix = XATTR_SECURITY_PREFIX, .get = kernfs_xattr_get, - .set = kernfs_security_xattr_set, + .set = kernfs_xattr_set, }; const struct xattr_handler *kernfs_xattr_handlers[] = { diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 3d83b114bb08..93bf1dcd0306 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -20,10 +20,9 @@ struct kernfs_iattrs { struct iattr ia_iattr; - void *ia_secdata; - u32 ia_secdata_len; - struct simple_xattrs xattrs; + struct simple_xattrs xattrs_trusted; + struct simple_xattrs xattrs_security; }; /* +1 to avoid triggering overflow warning when negating it */