[PATCH v3 08/15] LSM: drop bprm_secureexec hook

From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
	James Morris <james.l.morris@oracle.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	David Howells <dhowells@redhat.com>,
	John Johansen <john.johansen@canonical.com>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Paul Moore <paul@paul-moore.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Casey Schaufler <casey@schaufler-ca.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 08/15] LSM: drop bprm_secureexec hook
Date: Tue, 18 Jul 2017 15:25:29 -0700	[thread overview]
Message-ID: <1500416736-49829-9-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1500416736-49829-1-git-send-email-keescook@chromium.org>

This removes the bprm_secureexec hook since the logic has been folded into
the bprm_set_creds hook for all LSMs now.

Cc: James Morris <james.l.morris@oracle.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/binfmt_elf.c           |  1 -
 fs/binfmt_elf_fdpic.c     |  1 -
 include/linux/lsm_hooks.h | 14 +++++---------
 include/linux/security.h  |  7 -------
 security/security.c       |  5 -----
 5 files changed, 5 insertions(+), 23 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 991e4de3515f..7f6ec4dac13d 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -254,7 +254,6 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
 	NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
 	NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
 	NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
-	bprm->secureexec |= security_bprm_secureexec(bprm);
 	NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
 	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
 #ifdef ELF_HWCAP2
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index c88b35d4a6b3..5aa9199dfb13 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -650,7 +650,6 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
 	NEW_AUX_ENT(AT_GID,	(elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
 	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
-	bprm->secureexec |= security_bprm_secureexec(bprm);
 	NEW_AUX_ENT(AT_SECURE,	bprm->secureexec);
 	NEW_AUX_ENT(AT_EXECFN,	bprm->exec);
 
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 080f34e66017..2ddc1c7e8923 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -40,7 +40,11 @@
  *	interpreters.  The hook can tell whether it has already been called by
  *	checking to see if @bprm->security is non-NULL.  If so, then the hook
  *	may decide either to retain the security information saved earlier or
- *	to replace it.
+ *	to replace it.  The hook must set @bprm->secureexec to 1 if a "secure
+ *	exec" has happened as a result of this hook call.  The flag is used to
+ *	indicate the need for a sanitized execution environment, and is also
+ *	passed in the ELF auxiliary table on the initial stack to indicate
+ *	whether libc should enable secure mode.
  *	@bprm contains the linux_binprm structure.
  *	Return 0 if the hook is successful and permission is granted.
  * @bprm_check_security:
@@ -68,12 +72,6 @@
  *	linux_binprm structure.  This hook is a good place to perform state
  *	changes on the process such as clearing out non-inheritable signal
  *	state.  This is called immediately after commit_creds().
- * @bprm_secureexec:
- *	Return a boolean value (0 or 1) indicating whether a "secure exec"
- *	is required.  The flag is passed in the auxiliary table
- *	on the initial stack to the ELF interpreter to indicate whether libc
- *	should enable secure mode.
- *	@bprm contains the linux_binprm structure.
  *
  * Security hooks for filesystem operations.
  *
@@ -1368,7 +1366,6 @@ union security_list_options {
 
 	int (*bprm_set_creds)(struct linux_binprm *bprm);
 	int (*bprm_check_security)(struct linux_binprm *bprm);
-	int (*bprm_secureexec)(struct linux_binprm *bprm);
 	void (*bprm_committing_creds)(struct linux_binprm *bprm);
 	void (*bprm_committed_creds)(struct linux_binprm *bprm);
 
@@ -1680,7 +1677,6 @@ struct security_hook_heads {
 	struct list_head vm_enough_memory;
 	struct list_head bprm_set_creds;
 	struct list_head bprm_check_security;
-	struct list_head bprm_secureexec;
 	struct list_head bprm_committing_creds;
 	struct list_head bprm_committed_creds;
 	struct list_head sb_alloc_security;
diff --git a/include/linux/security.h b/include/linux/security.h
index af675b576645..133c41bb666d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -80,7 +80,6 @@ extern int cap_capset(struct cred *new, const struct cred *old,
 		      const kernel_cap_t *inheritable,
 		      const kernel_cap_t *permitted);
 extern int cap_bprm_set_creds(struct linux_binprm *bprm);
-extern int cap_bprm_secureexec(struct linux_binprm *bprm);
 extern int cap_inode_setxattr(struct dentry *dentry, const char *name,
 			      const void *value, size_t size, int flags);
 extern int cap_inode_removexattr(struct dentry *dentry, const char *name);
@@ -223,7 +222,6 @@ int security_bprm_set_creds(struct linux_binprm *bprm);
 int security_bprm_check(struct linux_binprm *bprm);
 void security_bprm_committing_creds(struct linux_binprm *bprm);
 void security_bprm_committed_creds(struct linux_binprm *bprm);
-int security_bprm_secureexec(struct linux_binprm *bprm);
 int security_sb_alloc(struct super_block *sb);
 void security_sb_free(struct super_block *sb);
 int security_sb_copy_data(char *orig, char *copy);
@@ -515,11 +513,6 @@ static inline void security_bprm_committed_creds(struct linux_binprm *bprm)
 {
 }
 
-static inline int security_bprm_secureexec(struct linux_binprm *bprm)
-{
-	return cap_bprm_secureexec(bprm);
-}
-
 static inline int security_sb_alloc(struct super_block *sb)
 {
 	return 0;
diff --git a/security/security.c b/security/security.c
index b9fea3999cf8..750b83186869 100644
--- a/security/security.c
+++ b/security/security.c
@@ -311,11 +311,6 @@ void security_bprm_committed_creds(struct linux_binprm *bprm)
 	call_void_hook(bprm_committed_creds, bprm);
 }
 
-int security_bprm_secureexec(struct linux_binprm *bprm)
-{
-	return call_int_hook(bprm_secureexec, 0, bprm);
-}
-
 int security_sb_alloc(struct super_block *sb)
 {
 	return call_int_hook(sb_alloc_security, 0, sb);
-- 
2.7.4
