[RFC PATCH v2 06/11] kexec: replace call to copy_file_from_fd() with kernel version
Mimi Zohar
zohar at linux.vnet.ibm.com
Mon Jan 18 07:11:21 PST 2016
This patch defines kernel_read_file_from_fd(), a wrapper for the VFS
common kernel_read_file(), and replaces the kexec copy_file_from_fd()
calls with the kernel_read_file_from_fd() wrapper.
Two new IMA policy identifiers named KEXEC_CHECK and INITRAMFS_CHECK
are defined for measuring, appraising or auditing the kexec image
and initramfs.
Changelog v1:
- re-order and squash the kexec patches
v3: ima: measure and appraise kexec image and initramfs (squashed)
- rename ima_read_hooks enumeration to ima_policy_id
- use kstat file size type loff_t, not size_t
- add union name "hooks" to fix sparse warning
v2:
- Calculate the file hash from the in memory buffer
(suggested by Dave Young)
- Rename ima_read_and_process_file() to ima_hash_and_process_file()
- replace individual case statements with range:
KEXEC_CHECK ... IMA_MAX_READ_CHECK - 1
v1:
- Instead of ima_read_and_process_file() allocating memory, the caller
allocates and frees the memory.
- Moved the kexec measurement/appraisal call to copy_file_from_fd(). The
same call now measures and appraises both the kexec image and initramfs.
Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>
---
Documentation/ABI/testing/ima_policy | 2 +-
fs/exec.c | 15 ++++++++
include/linux/fs.h | 1 +
include/linux/ima.h | 2 +
kernel/kexec_file.c | 72 ++++-------------------------------
security/integrity/ima/ima.h | 9 ++++-
security/integrity/ima/ima_appraise.c | 7 ++++
security/integrity/ima/ima_policy.c | 27 ++++++++++---
8 files changed, 64 insertions(+), 71 deletions(-)
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 0a378a8..e80f767 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -26,7 +26,7 @@ Description:
option: [[appraise_type=]] [permit_directio]
base: func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK]
- [FIRMWARE_CHECK]
+ [FIRMWARE_CHECK] [KEXEC_CHECK] [INITRAMFS_CHECK]
mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
[[^]MAY_EXEC]
fsmagic:= hex value
diff --git a/fs/exec.c b/fs/exec.c
index 211b81c..a5ae51e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -884,6 +884,21 @@ out:
}
EXPORT_SYMBOL_GPL(kernel_read_file);
+int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
+ int policy_id)
+{
+ struct fd f = fdget(fd);
+ int ret = -ENOEXEC;
+
+ if (!f.file)
+ goto out;
+
+ ret = kernel_read_file(f.file, buf, size, max_size, policy_id);
+out:
+ fdput(f);
+ return ret;
+}
+
ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
{
ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9b1468c..9642623 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2528,6 +2528,7 @@ extern int do_pipe_flags(int *, int);
extern int kernel_read(struct file *, loff_t, char *, unsigned long);
extern int kernel_read_file(struct file *, void **, loff_t *, loff_t, int);
+extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t, int);
extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
extern struct file * open_exec(const char *);
diff --git a/include/linux/ima.h b/include/linux/ima.h
index ca76f60..ae91938 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -14,6 +14,8 @@
struct linux_binprm;
enum ima_policy_id {
+ KEXEC_CHECK = 1,
+ INITRAMFS_CHECK,
IMA_MAX_READ_CHECK
};
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b70ada0..f7c3ce4 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -18,6 +18,7 @@
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
+#include <linux/ima.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <linux/syscalls.h>
@@ -33,65 +34,6 @@ size_t __weak kexec_purgatory_size = 0;
static int kexec_calculate_store_digests(struct kimage *image);
-static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
-{
- struct fd f = fdget(fd);
- int ret;
- struct kstat stat;
- loff_t pos;
- ssize_t bytes = 0;
-
- if (!f.file)
- return -EBADF;
-
- ret = vfs_getattr(&f.file->f_path, &stat);
- if (ret)
- goto out;
-
- if (stat.size > INT_MAX) {
- ret = -EFBIG;
- goto out;
- }
-
- /* Don't hand 0 to vmalloc, it whines. */
- if (stat.size == 0) {
- ret = -EINVAL;
- goto out;
- }
-
- *buf = vmalloc(stat.size);
- if (!*buf) {
- ret = -ENOMEM;
- goto out;
- }
-
- pos = 0;
- while (pos < stat.size) {
- bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
- stat.size - pos);
- if (bytes < 0) {
- vfree(*buf);
- ret = bytes;
- goto out;
- }
-
- if (bytes == 0)
- break;
- pos += bytes;
- }
-
- if (pos != stat.size) {
- ret = -EBADF;
- vfree(*buf);
- goto out;
- }
-
- *buf_len = pos;
-out:
- fdput(f);
- return ret;
-}
-
/* Architectures can provide this probe function */
int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
unsigned long buf_len)
@@ -180,16 +122,17 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
{
int ret = 0;
void *ldata;
+ loff_t size;
- ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
- &image->kernel_buf_len);
+ ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
+ &size, INT_MAX, KEXEC_CHECK);
if (ret)
return ret;
+ image->kernel_buf_len = size;
/* Call arch image probe handlers */
ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
image->kernel_buf_len);
-
if (ret)
goto out;
@@ -204,10 +147,11 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
#endif
/* It is possible that there no initramfs is being loaded */
if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
- ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
- &image->initrd_buf_len);
+ ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
+ &size, INT_MAX, INITRAMFS_CHECK);
if (ret)
goto out;
+ image->initrd_buf_len = size;
}
if (cmdline_len) {
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 06bcc24..b98dbd5 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -160,7 +160,14 @@ void ima_free_template_entry(struct ima_template_entry *entry);
const char *ima_d_path(struct path *path, char **pathbuf);
/* IMA policy related functions */
-enum ima_hooks { FILE_CHECK = 1, MMAP_CHECK, BPRM_CHECK, MODULE_CHECK, FIRMWARE_CHECK, POST_SETATTR };
+enum ima_hooks {
+ FILE_CHECK = IMA_MAX_READ_CHECK,
+ MMAP_CHECK,
+ BPRM_CHECK,
+ MODULE_CHECK,
+ FIRMWARE_CHECK,
+ POST_SETATTR
+};
int ima_match_policy(struct inode *inode, int func, int mask, int flags);
void ima_init_policy(void);
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 4edf47f..3adf937 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -78,6 +78,8 @@ enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
return iint->ima_module_status;
case FIRMWARE_CHECK:
return iint->ima_firmware_status;
+ case KEXEC_CHECK ... IMA_MAX_READ_CHECK - 1:
+ return iint->ima_read_status;
case FILE_CHECK:
default:
return iint->ima_file_status;
@@ -100,6 +102,9 @@ static void ima_set_cache_status(struct integrity_iint_cache *iint,
case FIRMWARE_CHECK:
iint->ima_firmware_status = status;
break;
+ case KEXEC_CHECK ... IMA_MAX_READ_CHECK - 1:
+ iint->ima_read_status = status;
+ break;
case FILE_CHECK:
default:
iint->ima_file_status = status;
@@ -122,6 +127,8 @@ static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
case FIRMWARE_CHECK:
iint->flags |= (IMA_FIRMWARE_APPRAISED | IMA_APPRAISED);
break;
+ case KEXEC_CHECK ... IMA_MAX_READ_CHECK - 1:
+ break;
case FILE_CHECK:
default:
iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 595e038..4711083 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -306,6 +306,8 @@ static int get_subaction(struct ima_rule_entry *rule, int func)
return IMA_MODULE_APPRAISE;
case FIRMWARE_CHECK:
return IMA_FIRMWARE_APPRAISE;
+ case KEXEC_CHECK ... IMA_MAX_READ_CHECK - 1:
+ return IMA_READ_APPRAISE;
case FILE_CHECK:
default:
return IMA_FILE_APPRAISE;
@@ -614,6 +616,10 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
entry->hooks.func = MMAP_CHECK;
else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
entry->hooks.func = BPRM_CHECK;
+ else if (strcmp(args[0].from, "KEXEC_CHECK") == 0)
+ entry->hooks.policy_id = KEXEC_CHECK;
+ else if (strcmp(args[0].from, "INITRAMFS_CHECK") == 0)
+ entry->hooks.policy_id = INITRAMFS_CHECK;
else
result = -EINVAL;
if (!result)
@@ -867,7 +873,9 @@ static char *func_tokens[] = {
"BPRM_CHECK",
"MODULE_CHECK",
"FIRMWARE_CHECK",
- "POST_SETATTR"
+ "POST_SETATTR",
+ "KEXEC_CHECK",
+ "INITRAMFS_CHECK",
};
void *ima_policy_start(struct seq_file *m, loff_t *pos)
@@ -948,10 +956,19 @@ int ima_policy_show(struct seq_file *m, void *v)
seq_printf(m, pt(Opt_func), ft(func_post));
break;
default:
- snprintf(tbuf, sizeof(tbuf), "%d",
- entry->hooks.func);
- seq_printf(m, pt(Opt_func), tbuf);
- break;
+ switch (entry->hooks.policy_id) {
+ case KEXEC_CHECK:
+ seq_printf(m, pt(Opt_func), ft(func_kexec));
+ break;
+ case INITRAMFS_CHECK:
+ seq_printf(m, pt(Opt_func), ft(func_initramfs));
+ break;
+ default:
+ snprintf(tbuf, sizeof(tbuf), "%d",
+ entry->hooks.func);
+ seq_printf(m, pt(Opt_func), tbuf);
+ break;
+ }
}
seq_puts(m, " ");
}
--
2.1.0
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