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patch-capfix-2.4.18
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diff -urN linux-2.4.18-4-capfix/Documentation/Configure.help linux-2.4.18-4/Documentation/Configure.help
--- linux-2.4.18-4-capfix/Documentation/Configure.help Tue May 28 11:42:35 2002
+++ linux-2.4.18-4/Documentation/Configure.help Thu May 2 14:36:41 2002
@@ -3775,22 +3775,6 @@
building a kernel for install/rescue disks or your system is very
limited in memory.
-Inherit Capabilities Across Exec
-CONFIG_INHERIT_CAPS_ACROSS_EXEC
- Allow non-root users to pass on capabilities when they exec
- binaries. When this feature is used in combination with a
- user-level capability assignment mechanism (e.g. pam_capability)
- it can significantly reduce the amount of time that users need
- to run as root.
-
- Note that this is a temporary solution to the larger
- problem of implementing full support for capabilities in
- the Linux virtual file system layer.
-
- You should say N here unless you know what this is and know
- that you want to use it.
-
-
# Choice: kcore
Kernel core (/proc/kcore) format
CONFIG_KCORE_ELF
diff -urN linux-2.4.18-4-capfix/Makefile linux-2.4.18-4/Makefile
--- linux-2.4.18-4-capfix/Makefile Tue May 28 11:42:49 2002
+++ linux-2.4.18-4/Makefile Thu May 2 15:19:06 2002
@@ -1,7 +1,7 @@
VERSION = 2
PATCHLEVEL = 4
SUBLEVEL = 18
-EXTRAVERSION = -capfix
+EXTRAVERSION =
KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
diff -urN linux-2.4.18-4-capfix/arch/i386/config.in linux-2.4.18-4/arch/i386/config.in
--- linux-2.4.18-4-capfix/arch/i386/config.in Tue May 28 11:42:35 2002
+++ linux-2.4.18-4/arch/i386/config.in Thu May 2 14:36:43 2002
@@ -271,9 +271,6 @@
bool 'System V IPC' CONFIG_SYSVIPC
bool 'BSD Process Accounting' CONFIG_BSD_PROCESS_ACCT
bool 'Sysctl support' CONFIG_SYSCTL
-if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
- bool 'Inherit Capabilities Across Exec' CONFIG_INHERIT_CAPS_ACROSS_EXEC
-fi
if [ "$CONFIG_PROC_FS" = "y" ]; then
choice 'Kernel core (/proc/kcore) format' \
"ELF CONFIG_KCORE_ELF \
diff -urN linux-2.4.18-4-capfix/fs/exec.c linux-2.4.18-4/fs/exec.c
--- linux-2.4.18-4-capfix/fs/exec.c Tue May 28 11:42:35 2002
+++ linux-2.4.18-4/fs/exec.c Thu May 2 14:36:34 2002
@@ -652,29 +652,6 @@
cap_clear(bprm->cap_permitted);
cap_clear(bprm->cap_effective);
-#ifdef CONFIG_INHERIT_CAPS_ACROSS_EXEC
- /* allow non-root users to pass on capabilities
- * when they exec binaries. we leave all capabilities
- * cleared if cap_setpcap is set in any of the capability
- * sets as a marker to indicate that an application did not
- * call sys_capset via * cap_set_proc.
- *
- * NB: this means that non-root users can never be granted
- * cap_setpcap. This isn't necessarily * a bad thing.
- *
- * NB: we use cap_inheritable here so that login can set
- * setuid/setgid in eff & perm for purposes of su, which
- * can then go away silently.
- */
- if ( (current->euid != 0 || issecure(SECURE_NOROOT)) &&
- !(cap_raised(current->cap_inheritable,CAP_SETPCAP)) &&
- !(cap_raised(current->cap_effective,CAP_SETPCAP)) &&
- !(cap_raised(current->cap_permitted,CAP_SETPCAP)) ) {
- bprm->cap_permitted = current->cap_inheritable;
- bprm->cap_effective = current->cap_inheritable;
- }
-#endif
-
/* To support inheritance of root-permissions and suid-root
* executables under compatibility mode, we raise all three
* capability sets for the file.
diff -urN linux-2.4.18-4-capfix/fs/open.c linux-2.4.18-4/fs/open.c
--- linux-2.4.18-4-capfix/fs/open.c Mon Jul 1 09:21:34 2002
+++ linux-2.4.18-4/fs/open.c Fri Oct 12 13:48:42 2001
@@ -333,14 +333,7 @@
current->fsuid = current->uid;
current->fsgid = current->gid;
- /*
- * Clear the capabilities if we switch to a non-root user
- *
- * FIXME: There is a race here against sys_capset. The
- * capabilities can change yet we will restore the old
- * value below. We should hold task_capabilities_lock,
- * but we cannot because user_path_walk can sleep.
- */
+ /* Clear the capabilities if we switch to a non-root user */
if (current->uid)
cap_clear(current->cap_effective);
else
diff -urN linux-2.4.18-4-capfix/include/linux/capability.h linux-2.4.18-4/include/linux/capability.h
--- linux-2.4.18-4-capfix/include/linux/capability.h Mon Jul 1 09:21:34 2002
+++ linux-2.4.18-4/include/linux/capability.h Thu May 2 15:10:28 2002
@@ -42,10 +42,6 @@
#ifdef __KERNEL__
-#include <linux/spinlock.h>
-
-extern spinlock_t task_capability_lock;
-
/* #define STRICT_CAP_T_TYPECHECKS */
#ifdef STRICT_CAP_T_TYPECHECKS
diff -urN linux-2.4.18-4-capfix/kernel/capability.c linux-2.4.18-4/kernel/capability.c
--- linux-2.4.18-4-capfix/kernel/capability.c Mon Jul 1 09:21:34 2002
+++ linux-2.4.18-4/kernel/capability.c Thu May 2 14:36:31 2002
@@ -2,21 +2,17 @@
* linux/kernel/capability.c
*
* Copyright (C) 1997 Andrew Main <[email protected]>
- *
* Integrated into 2.1.97+, Andrew G. Morgan <[email protected]>
- * 30 May 2002: Cleanup, Robert M. Love <[email protected]>
*/
#include <linux/mm.h>
#include <asm/uaccess.h>
unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
+
kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
-/*
- * This global lock protects task->cap_* for all tasks including current.
- * Locking rule: acquire this prior to tasklist_lock.
- */
+/* Note: never hold tasklist_lock while spinning for this one */
spinlock_t task_capability_lock = SPIN_LOCK_UNLOCKED;
/*
@@ -25,24 +21,23 @@
* uninteresting and/or not to be changed.
*/
-/*
- * sys_capget - get the capabilities of a given process.
- */
asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
- int ret = 0;
- pid_t pid;
+ int error, pid;
__u32 version;
- task_t *target;
+ struct task_struct *target;
struct __user_cap_data_struct data;
if (get_user(version, &header->version))
return -EFAULT;
-
- if (version != _LINUX_CAPABILITY_VERSION)
- if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
- return -EFAULT;
- return -EINVAL;
+
+ error = -EINVAL;
+ if (version != _LINUX_CAPABILITY_VERSION) {
+ version = _LINUX_CAPABILITY_VERSION;
+ if (put_user(version, &header->version))
+ error = -EFAULT;
+ return error;
+ }
if (get_user(pid, &header->pid))
return -EFAULT;
@@ -50,39 +45,48 @@
if (pid < 0)
return -EINVAL;
+ error = 0;
+
spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
- target = find_task_by_pid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
+ if (pid && pid != current->pid) {
+ read_lock(&tasklist_lock);
+ target = find_task_by_pid(pid); /* identify target of query */
+ if (!target)
+ error = -ESRCH;
+ } else {
+ target = current;
}
- data.permitted = cap_t(target->cap_permitted);
- data.inheritable = cap_t(target->cap_inheritable);
- data.effective = cap_t(target->cap_effective);
+ if (!error) {
+ data.permitted = cap_t(target->cap_permitted);
+ data.inheritable = cap_t(target->cap_inheritable);
+ data.effective = cap_t(target->cap_effective);
+ }
-out:
- read_unlock(&tasklist_lock);
+ if (target != current)
+ read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
- if (!ret && copy_to_user(dataptr, &data, sizeof data))
- return -EFAULT;
+ if (!error) {
+ if (copy_to_user(dataptr, &data, sizeof data))
+ return -EFAULT;
+ }
- return ret;
+ return error;
}
-/*
- * cap_set_pg - set capabilities for all processes in a given process
- * group. We call this holding task_capability_lock and tasklist_lock.
- */
-static inline void cap_set_pg(int pgrp, kernel_cap_t *effective,
- kernel_cap_t *inheritable,
- kernel_cap_t *permitted)
+/* set capabilities for all processes in a given process group */
+
+static void cap_set_pg(int pgrp,
+ kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
{
- task_t *target;
+ struct task_struct *target;
+ /* FIXME: do we need to have a write lock here..? */
+ read_lock(&tasklist_lock);
for_each_task(target) {
if (target->pgrp != pgrp)
continue;
@@ -90,18 +94,20 @@
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
+ read_unlock(&tasklist_lock);
}
-/*
- * cap_set_all - set capabilities for all processes other than init
- * and self. We call this holding task_capability_lock and tasklist_lock.
- */
-static inline void cap_set_all(kernel_cap_t *effective,
- kernel_cap_t *inheritable,
- kernel_cap_t *permitted)
+/* set capabilities for all processes other than 1 and self */
+
+static void cap_set_all(kernel_cap_t *effective,
+ kernel_cap_t *inheritable,
+ kernel_cap_t *permitted)
{
- task_t *target;
+ struct task_struct *target;
+ /* FIXME: do we need to have a write lock here..? */
+ read_lock(&tasklist_lock);
+ /* ALL means everyone other than self or 'init' */
for_each_task(target) {
if (target == current || target->pid == 1)
continue;
@@ -109,35 +115,35 @@
target->cap_inheritable = *inheritable;
target->cap_permitted = *permitted;
}
+ read_unlock(&tasklist_lock);
}
/*
- * sys_capset - set capabilities for a given process, all processes, or all
- * processes in a given process group.
- *
* The restrictions on setting capabilities are specified as:
*
* [pid is for the 'target' task. 'current' is the calling task.]
*
- * I: any raised capabilities must be a subset of the (old current) permitted
+ * I: any raised capabilities must be a subset of the (old current) Permitted
* P: any raised capabilities must be a subset of the (old current) permitted
- * E: must be set to a subset of (new target) permitted
+ * E: must be set to a subset of (new target) Permitted
*/
+
asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
{
kernel_cap_t inheritable, permitted, effective;
__u32 version;
- task_t *target;
- int ret;
- pid_t pid;
+ struct task_struct *target;
+ int error, pid;
if (get_user(version, &header->version))
return -EFAULT;
- if (version != _LINUX_CAPABILITY_VERSION)
- if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
+ if (version != _LINUX_CAPABILITY_VERSION) {
+ version = _LINUX_CAPABILITY_VERSION;
+ if (put_user(version, &header->version))
return -EFAULT;
return -EINVAL;
+ }
if (get_user(pid, &header->pid))
return -EFAULT;
@@ -150,35 +156,43 @@
copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
return -EFAULT;
+ error = -EPERM;
spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
if (pid > 0 && pid != current->pid) {
- target = find_task_by_pid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
- }
- } else
- target = current;
+ read_lock(&tasklist_lock);
+ target = find_task_by_pid(pid); /* identify target of query */
+ if (!target) {
+ error = -ESRCH;
+ goto out;
+ }
+ } else {
+ target = current;
+ }
- ret = -EPERM;
/* verify restrictions on target's new Inheritable set */
- if (!cap_issubset(inheritable, cap_combine(target->cap_inheritable,
- current->cap_permitted)))
+ if (!cap_issubset(inheritable,
+ cap_combine(target->cap_inheritable,
+ current->cap_permitted))) {
goto out;
+ }
/* verify restrictions on target's new Permitted set */
- if (!cap_issubset(permitted, cap_combine(target->cap_permitted,
- current->cap_permitted)))
+ if (!cap_issubset(permitted,
+ cap_combine(target->cap_permitted,
+ current->cap_permitted))) {
goto out;
+ }
/* verify the _new_Effective_ is a subset of the _new_Permitted_ */
- if (!cap_issubset(effective, permitted))
+ if (!cap_issubset(effective, permitted)) {
goto out;
+ }
- ret = 0;
+ /* having verified that the proposed changes are legal,
+ we now put them into effect. */
+ error = 0;
if (pid < 0) {
if (pid == -1) /* all procs other than current and init */
@@ -186,15 +200,19 @@
else /* all procs in process group */
cap_set_pg(-pid, &effective, &inheritable, &permitted);
+ goto spin_out;
} else {
+ /* FIXME: do we need to have a write lock here..? */
target->cap_effective = effective;
target->cap_inheritable = inheritable;
target->cap_permitted = permitted;
}
out:
- read_unlock(&tasklist_lock);
+ if (target != current) {
+ read_unlock(&tasklist_lock);
+ }
+spin_out:
spin_unlock(&task_capability_lock);
-
- return ret;
+ return error;
}