From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Dickson Subject: [PATCH 04/17] Security: Add hook to calculate context based on a negative dentry. Date: Thu, 2 May 2013 13:18:58 -0400 Message-ID: <1367515151-31015-5-git-send-email-SteveD@redhat.com> References: <1367515151-31015-1-git-send-email-SteveD@redhat.com> Cc: Linux NFS list , Linux FS devel list , Linux Security List , SELinux List To: Trond Myklebust , "J. Bruce Fields" , "David P. Quigley" Return-path: In-Reply-To: <1367515151-31015-1-git-send-email-SteveD@redhat.com> Sender: linux-security-module-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: David Quigley There is a time where we need to calculate a context without the inode having been created yet. To do this we take the negative dentry and calculate a context based on the process and the parent directory contexts. Signed-off-by: Matthew N. Dodd Signed-off-by: Miguel Rodel Felipe Signed-off-by: Phua Eu Gene Signed-off-by: Khin Mi Mi Aung --- include/linux/security.h | 27 +++++++++++++++++++++++++++ security/capability.c | 8 ++++++++ security/security.c | 10 ++++++++++ security/selinux/hooks.c | 35 +++++++++++++++++++++++++++++++++++ 4 files changed, 80 insertions(+) diff --git a/include/linux/security.h b/include/linux/security.h index 032c366..f3d7956 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -26,6 +26,7 @@ #include #include #include +#include struct linux_binprm; struct cred; @@ -306,6 +307,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * Parse a string of security data filling in the opts structure * @options string containing all mount options known by the LSM * @opts binary data structure usable by the LSM + * @dentry_init_security: + * Compute a context for a dentry as the inode is not yet available + * since NFSv4 has no label backed by an EA anyway. + * @dentry dentry to use in calculating the context. + * @mode mode used to determine resource type. + * @name name of the last path component used to create file + * @ctx pointer to place the pointer to the resulting context in. + * @ctxlen point to place the length of the resulting context. + * * * Security hooks for inode operations. * @@ -1443,6 +1453,10 @@ struct security_operations { void (*sb_clone_mnt_opts) (const struct super_block *oldsb, struct super_block *newsb); int (*sb_parse_opts_str) (char *options, struct security_mnt_opts *opts); + int (*dentry_init_security) (struct dentry *dentry, int mode, + struct qstr *name, void **ctx, + u32 *ctxlen); + #ifdef CONFIG_SECURITY_PATH int (*path_unlink) (struct path *dir, struct dentry *dentry); @@ -1729,6 +1743,9 @@ int security_sb_set_mnt_opts(struct super_block *sb, struct security_mnt_opts *o void security_sb_clone_mnt_opts(const struct super_block *oldsb, struct super_block *newsb); int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts); +int security_dentry_init_security(struct dentry *dentry, int mode, + struct qstr *name, void **ctx, + u32 *ctxlen); int security_inode_alloc(struct inode *inode); void security_inode_free(struct inode *inode); @@ -2033,6 +2050,16 @@ static inline int security_inode_alloc(struct inode *inode) static inline void security_inode_free(struct inode *inode) { } +static inline int security_dentry_init_security(struct dentry *dentry, + int mode, + struct qstr *name, + void **ctx, + u32 *ctxlen) +{ + return -EOPNOTSUPP; +} + + static inline int security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, diff --git a/security/capability.c b/security/capability.c index 6783c3e..782045e 100644 --- a/security/capability.c +++ b/security/capability.c @@ -108,6 +108,13 @@ static int cap_sb_parse_opts_str(char *options, struct security_mnt_opts *opts) return 0; } +static int cap_dentry_init_security(struct dentry *dentry, int mode, + struct qstr *name, void **ctx, + u32 *ctxlen) +{ + return 0; +} + static int cap_inode_alloc_security(struct inode *inode) { return 0; @@ -930,6 +937,7 @@ void __init security_fixup_ops(struct security_operations *ops) set_to_cap_if_null(ops, sb_set_mnt_opts); set_to_cap_if_null(ops, sb_clone_mnt_opts); set_to_cap_if_null(ops, sb_parse_opts_str); + set_to_cap_if_null(ops, dentry_init_security); set_to_cap_if_null(ops, inode_alloc_security); set_to_cap_if_null(ops, inode_free_security); set_to_cap_if_null(ops, inode_init_security); diff --git a/security/security.c b/security/security.c index 03f248b..7c18e3c 100644 --- a/security/security.c +++ b/security/security.c @@ -12,6 +12,7 @@ */ #include +#include #include #include #include @@ -324,6 +325,15 @@ void security_inode_free(struct inode *inode) security_ops->inode_free_security(inode); } +int security_dentry_init_security(struct dentry *dentry, int mode, + struct qstr *name, void **ctx, + u32 *ctxlen) +{ + return security_ops->dentry_init_security(dentry, mode, name, + ctx, ctxlen); +} +EXPORT_SYMBOL(security_dentry_init_security); + int security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const initxattrs initxattrs, void *fs_data) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 7171a95..622b205 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2484,6 +2484,40 @@ static void selinux_inode_free_security(struct inode *inode) inode_free_security(inode); } +static int selinux_dentry_init_security(struct dentry *dentry, int mode, + struct qstr *name, void **ctx, + u32 *ctxlen) +{ + const struct cred *cred = current_cred(); + struct task_security_struct *tsec; + struct inode_security_struct *dsec; + struct superblock_security_struct *sbsec; + struct inode *dir = dentry->d_parent->d_inode; + u32 newsid; + int rc; + + tsec = cred->security; + dsec = dir->i_security; + sbsec = dir->i_sb->s_security; + + if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) { + newsid = tsec->create_sid; + } else { + rc = security_transition_sid(tsec->sid, dsec->sid, + inode_mode_to_security_class(mode), + name, + &newsid); + if (rc) { + printk(KERN_WARNING + "%s: security_transition_sid failed, rc=%d\n", + __func__, -rc); + return rc; + } + } + + return security_sid_to_context(newsid, (char **)ctx, ctxlen); +} + static int selinux_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, char **name, void **value, size_t *len) @@ -5531,6 +5565,7 @@ static struct security_operations selinux_ops = { .sb_clone_mnt_opts = selinux_sb_clone_mnt_opts, .sb_parse_opts_str = selinux_parse_opts_str, + .dentry_init_security = selinux_dentry_init_security, .inode_alloc_security = selinux_inode_alloc_security, .inode_free_security = selinux_inode_free_security, -- 1.8.1.4