lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Add 64-bit capability support to the kernel

Browse Source 
The patch supports legacy (32-bit) capability userspace, and where possible
translates 32-bit capabilities to/from userspace and the VFS to 64-bit
kernel space capabilities.  If a capability set cannot be compressed into
32-bits for consumption by user space, the system call fails, with -ERANGE.

FWIW libcap-2.00 supports this change (and earlier capability formats)

 http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/

[akpm@linux-foundation.org: coding-syle fixes]
[akpm@linux-foundation.org: use get_task_comm()]
[ezk@cs.sunysb.edu: build fix]
[akpm@linux-foundation.org: do not initialise statics to 0 or NULL]
[akpm@linux-foundation.org: unused var]
[serue@us.ibm.com: export __cap_ symbols]
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrew Morgan
2008-02-04 22:29:42 -08:00
committed by Linus Torvalds
parent 8f6936f4d2
commit e338d263a7
7 changed files with 349 additions and 125 deletions
Download Patch File Download Diff File Expand all files Collapse all files

113
kernel/capability.c
View File

@@ -21,6 +21,37 @@
*/
static DEFINE_SPINLOCK(task_capability_lock);
/*
* Leveraged for setting/resetting capabilities
*/
const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
const kernel_cap_t __cap_full_set = CAP_FULL_SET;
const kernel_cap_t __cap_init_eff_set = CAP_INIT_EFF_SET;
EXPORT_SYMBOL(__cap_empty_set);
EXPORT_SYMBOL(__cap_full_set);
EXPORT_SYMBOL(__cap_init_eff_set);
/*
* More recent versions of libcap are available from:
*
* http://www.kernel.org/pub/linux/libs/security/linux-privs/
*/
static void warn_legacy_capability_use(void)
{
static int warned;
if (!warned) {
char name[sizeof(current->comm)];
printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
" (legacy support in use)\n",
get_task_comm(name, current));
warned = 1;
}
}
/*
* For sys_getproccap() and sys_setproccap(), any of the three
* capability set pointers may be NULL -- indicating that that set is
@@ -42,12 +73,21 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
pid_t pid;
__u32 version;
struct task_struct *target;
struct __user_cap_data_struct data;
unsigned tocopy;
kernel_cap_t pE, pI, pP;
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
switch (version) {
case _LINUX_CAPABILITY_VERSION_1:
warn_legacy_capability_use();
tocopy = _LINUX_CAPABILITY_U32S_1;
break;
case _LINUX_CAPABILITY_VERSION_2:
tocopy = _LINUX_CAPABILITY_U32S_2;
break;
default:
if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
@@ -71,14 +111,47 @@ asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
} else
target = current;
ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
ret = security_capget(target, &pE, &pI, &pP);
out:
read_unlock(&tasklist_lock);
spin_unlock(&task_capability_lock);
if (!ret && copy_to_user(dataptr, &data, sizeof data))
return -EFAULT;
if (!ret) {
struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
unsigned i;
for (i = 0; i < tocopy; i++) {
kdata[i].effective = pE.cap[i];
kdata[i].permitted = pP.cap[i];
kdata[i].inheritable = pI.cap[i];
}
/*
* Note, in the case, tocopy < _LINUX_CAPABILITY_U32S,
* we silently drop the upper capabilities here. This
* has the effect of making older libcap
* implementations implicitly drop upper capability
* bits when they perform a: capget/modify/capset
* sequence.
*
* This behavior is considered fail-safe
* behavior. Upgrading the application to a newer
* version of libcap will enable access to the newer
* capabilities.
*
* An alternative would be to return an error here
* (-ERANGE), but that causes legacy applications to
* unexpectidly fail; the capget/modify/capset aborts
* before modification is attempted and the application
* fails.
*/
if (copy_to_user(dataptr, kdata, tocopy
* sizeof(struct __user_cap_data_struct))) {
return -EFAULT;
}
}
return ret;
}
@@ -167,6 +240,8 @@ static inline int cap_set_all(kernel_cap_t *effective,
*/
asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
{
struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
unsigned i, tocopy;
kernel_cap_t inheritable, permitted, effective;
__u32 version;
struct task_struct *target;
@@ -176,7 +251,15 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
if (get_user(version, &header->version))
return -EFAULT;
if (version != _LINUX_CAPABILITY_VERSION) {
switch (version) {
case _LINUX_CAPABILITY_VERSION_1:
warn_legacy_capability_use();
tocopy = _LINUX_CAPABILITY_U32S_1;
break;
case _LINUX_CAPABILITY_VERSION_2:
tocopy = _LINUX_CAPABILITY_U32S_2;
break;
default:
if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
@@ -188,10 +271,22 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
return -EPERM;
if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
if (copy_from_user(&kdata, data, tocopy
* sizeof(struct __user_cap_data_struct))) {
return -EFAULT;
}
for (i = 0; i < tocopy; i++) {
effective.cap[i] = kdata[i].effective;
permitted.cap[i] = kdata[i].permitted;
inheritable.cap[i] = kdata[i].inheritable;
}
while (i < _LINUX_CAPABILITY_U32S) {
effective.cap[i] = 0;
permitted.cap[i] = 0;
inheritable.cap[i] = 0;
i++;
}
spin_lock(&task_capability_lock);
read_lock(&tasklist_lock);