[PATCH 58/59] CRED: Wrap task credential accesses in the capabilities code

David Howells
2008-08-27T14:03:57Z

Cc: Andrew G. Morgan <morgan@kernel.org>
---

security/commoncap.c | 31 +++++++++++++++++++------------
1 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index e4c4b3f..583cfc3 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -345,7 +345,7 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
* If only the real uid is 0, we do not set the effective
* bit.
*/
- if (bprm->e_uid == 0 || current->uid == 0) {
+ if (bprm->e_uid == 0 || current_uid() == 0) {
/* pP' = (cap_bset & ~0) | (pI & ~0) */
bprm->cap_post_exec_permitted = cap_combine(
current->cap_bset, current->cap_inheritable
@@ -360,7 +360,12 @@ int cap_bprm_set_security (struct linux_binprm *bprm)

void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
{
- if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
+ uid_t uid;
+ gid_t gid;
+
+ current_uid_gid(&uid, &gid);
+
+ if (bprm->e_uid != uid || bprm->e_gid != gid ||
!cap_issubset(bprm->cap_post_exec_permitted,
current->cap_permitted)) {
set_dumpable(current->mm, suid_dumpable);
@@ -368,8 +373,8 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)

if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
if (!capable(CAP_SETUID)) {
- bprm->e_uid = current->uid;
- bprm->e_gid = current->gid;
+ bprm->e_uid = uid;
+ bprm->e_gid = gid;
}
if (cap_limit_ptraced_target()) {
bprm->cap_post_exec_permitted = cap_intersect(
@@ -400,15 +405,15 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)

int cap_bprm_secureexec (struct linux_binprm *bprm)
{
- if (current->uid != 0) {
+ if (current_uid() != 0) {
if (bprm->cap_effective)
return 1;
if (!cap_isclear(bprm->cap_post_exec_permitted))
return 1;
}

- return (current->euid != current->uid ||
- current->egid != current->gid);
+ return (current_euid() != current_uid() ||
+ current_egid() != current_gid());
}

int cap_inode_setxattr(struct dentry *dentry, const char *name,
@@ -471,16 +476,18 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
int old_suid)
{
+ uid_t euid = current_euid();
+
if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
- (current->uid != 0 && current->euid != 0 && current->suid != 0) &&
+ (current_uid() != 0 && euid != 0 && current_suid() != 0) &&
!issecure(SECURE_KEEP_CAPS)) {
cap_clear (current->cap_permitted);
cap_clear (current->cap_effective);
}
- if (old_euid == 0 && current->euid != 0) {
+ if (old_euid == 0 && euid != 0) {
cap_clear (current->cap_effective);
}
- if (old_euid != 0 && current->euid == 0) {
+ if (old_euid != 0 && euid == 0) {
current->cap_effective = current->cap_permitted;
}
}
@@ -509,12 +516,12 @@ int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
*/

if (!issecure (SECURE_NO_SETUID_FIXUP)) {
- if (old_fsuid == 0 && current->fsuid != 0) {
+ if (old_fsuid == 0 && current_fsuid() != 0) {
current->cap_effective =
cap_drop_fs_set(
current->cap_effective);
}
- if (old_fsuid != 0 && current->fsuid == 0) {
+ if (old_fsuid != 0 && current_fsuid() == 0) {
current->cap_effective =
cap_raise_fs_set(
current->cap_effective,