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authorIngo Molnar <mingo@elte.hu>2009-09-02 08:17:56 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-02 08:17:56 +0200
commit936e894a976dd3b0f07f1f6f43c17b77b7e6146d (patch)
tree5ed5c1f6735dcd26550594df23c8f7fe2aa21a15 /security
parent69575d388603365f2afbf4166df93152df59b165 (diff)
parent326ba5010a5429a5a528b268b36a5900d4ab0eba (diff)
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Merge commit 'v2.6.31-rc8' into x86/txt
Conflicts: arch/x86/kernel/reboot.c security/Kconfig Merge reason: resolve the conflicts, bump up from rc3 to rc8. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'security')
-rw-r--r--security/Kconfig16
-rw-r--r--security/Makefile2
-rw-r--r--security/capability.c9
-rw-r--r--security/commoncap.c30
-rw-r--r--security/integrity/ima/ima_crypto.c6
-rw-r--r--security/integrity/ima/ima_main.c4
-rw-r--r--security/min_addr.c49
-rw-r--r--security/selinux/hooks.c17
8 files changed, 119 insertions, 14 deletions
diff --git a/security/Kconfig b/security/Kconfig
index 5721847a7a6..fb363cd81cf 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -143,6 +143,22 @@ config INTEL_TXT
If you are unsure as to whether this is required, answer N.
+config LSM_MMAP_MIN_ADDR
+ int "Low address space for LSM to protect from user allocation"
+ depends on SECURITY && SECURITY_SELINUX
+ default 65536
+ help
+ This is the portion of low virtual memory which should be protected
+ from userspace allocation. Keeping a user from writing to low pages
+ can help reduce the impact of kernel NULL pointer bugs.
+
+ For most ia64, ppc64 and x86 users with lots of address space
+ a value of 65536 is reasonable and should cause no problems.
+ On arm and other archs it should not be higher than 32768.
+ Programs which use vm86 functionality or have some need to map
+ this low address space will need the permission specific to the
+ systems running LSM.
+
source security/selinux/Kconfig
source security/smack/Kconfig
source security/tomoyo/Kconfig
diff --git a/security/Makefile b/security/Makefile
index c67557cdaa8..b56e7f9ecbc 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -8,7 +8,7 @@ subdir-$(CONFIG_SECURITY_SMACK) += smack
subdir-$(CONFIG_SECURITY_TOMOYO) += tomoyo
# always enable default capabilities
-obj-y += commoncap.o
+obj-y += commoncap.o min_addr.o
# Object file lists
obj-$(CONFIG_SECURITY) += security.o capability.o
diff --git a/security/capability.c b/security/capability.c
index 21b6cead6a8..88f752e8152 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -330,15 +330,6 @@ static int cap_file_ioctl(struct file *file, unsigned int command,
return 0;
}
-static int cap_file_mmap(struct file *file, unsigned long reqprot,
- unsigned long prot, unsigned long flags,
- unsigned long addr, unsigned long addr_only)
-{
- if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO))
- return -EACCES;
- return 0;
-}
-
static int cap_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
unsigned long prot)
{
diff --git a/security/commoncap.c b/security/commoncap.c
index 48b7e0228fa..e3097c0a131 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -984,3 +984,33 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
cap_sys_admin = 1;
return __vm_enough_memory(mm, pages, cap_sys_admin);
}
+
+/*
+ * cap_file_mmap - check if able to map given addr
+ * @file: unused
+ * @reqprot: unused
+ * @prot: unused
+ * @flags: unused
+ * @addr: address attempting to be mapped
+ * @addr_only: unused
+ *
+ * If the process is attempting to map memory below mmap_min_addr they need
+ * CAP_SYS_RAWIO. The other parameters to this function are unused by the
+ * capability security module. Returns 0 if this mapping should be allowed
+ * -EPERM if not.
+ */
+int cap_file_mmap(struct file *file, unsigned long reqprot,
+ unsigned long prot, unsigned long flags,
+ unsigned long addr, unsigned long addr_only)
+{
+ int ret = 0;
+
+ if (addr < dac_mmap_min_addr) {
+ ret = cap_capable(current, current_cred(), CAP_SYS_RAWIO,
+ SECURITY_CAP_AUDIT);
+ /* set PF_SUPERPRIV if it turns out we allow the low mmap */
+ if (ret == 0)
+ current->flags |= PF_SUPERPRIV;
+ }
+ return ret;
+}
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 63003a63aae..46642a19bc7 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -45,9 +45,9 @@ int ima_calc_hash(struct file *file, char *digest)
{
struct hash_desc desc;
struct scatterlist sg[1];
- loff_t i_size;
+ loff_t i_size, offset = 0;
char *rbuf;
- int rc, offset = 0;
+ int rc;
rc = init_desc(&desc);
if (rc != 0)
@@ -67,6 +67,8 @@ int ima_calc_hash(struct file *file, char *digest)
rc = rbuf_len;
break;
}
+ if (rbuf_len == 0)
+ break;
offset += rbuf_len;
sg_init_one(sg, rbuf, rbuf_len);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 101c512564e..4732f5e5d12 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -262,6 +262,8 @@ void ima_counts_put(struct path *path, int mask)
else if (mask & (MAY_READ | MAY_EXEC))
iint->readcount--;
mutex_unlock(&iint->mutex);
+
+ kref_put(&iint->refcount, iint_free);
}
/*
@@ -291,6 +293,8 @@ void ima_counts_get(struct file *file)
if (file->f_mode & FMODE_WRITE)
iint->writecount++;
mutex_unlock(&iint->mutex);
+
+ kref_put(&iint->refcount, iint_free);
}
EXPORT_SYMBOL_GPL(ima_counts_get);
diff --git a/security/min_addr.c b/security/min_addr.c
new file mode 100644
index 00000000000..14cc7b3b8d0
--- /dev/null
+++ b/security/min_addr.c
@@ -0,0 +1,49 @@
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/security.h>
+#include <linux/sysctl.h>
+
+/* amount of vm to protect from userspace access by both DAC and the LSM*/
+unsigned long mmap_min_addr;
+/* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
+unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
+/* amount of vm to protect from userspace using the LSM = CONFIG_LSM_MMAP_MIN_ADDR */
+
+/*
+ * Update mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR)
+ */
+static void update_mmap_min_addr(void)
+{
+#ifdef CONFIG_LSM_MMAP_MIN_ADDR
+ if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
+ mmap_min_addr = dac_mmap_min_addr;
+ else
+ mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
+#else
+ mmap_min_addr = dac_mmap_min_addr;
+#endif
+}
+
+/*
+ * sysctl handler which just sets dac_mmap_min_addr = the new value and then
+ * calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
+ */
+int mmap_min_addr_handler(struct ctl_table *table, int write, struct file *filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+
+ update_mmap_min_addr();
+
+ return ret;
+}
+
+int __init init_mmap_min_addr(void)
+{
+ update_mmap_min_addr();
+
+ return 0;
+}
+pure_initcall(init_mmap_min_addr);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 15c2a08a66f..8d8b69c5664 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1285,6 +1285,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
context, len);
if (rc == -ERANGE) {
+ kfree(context);
+
/* Need a larger buffer. Query for the right size. */
rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
NULL, 0);
@@ -1292,7 +1294,6 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
dput(dentry);
goto out_unlock;
}
- kfree(context);
len = rc;
context = kmalloc(len+1, GFP_NOFS);
if (!context) {
@@ -3029,9 +3030,21 @@ static int selinux_file_mmap(struct file *file, unsigned long reqprot,
int rc = 0;
u32 sid = current_sid();
- if (addr < mmap_min_addr)
+ /*
+ * notice that we are intentionally putting the SELinux check before
+ * the secondary cap_file_mmap check. This is such a likely attempt
+ * at bad behaviour/exploit that we always want to get the AVC, even
+ * if DAC would have also denied the operation.
+ */
+ if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
MEMPROTECT__MMAP_ZERO, NULL);
+ if (rc)
+ return rc;
+ }
+
+ /* do DAC check on address space usage */
+ rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
if (rc || addr_only)
return rc;