[PATCH 3.16 004/134] ima: pass 'opened' flag to identify newly created files

Ben Hutchings
2017-08-18T13:15:41Z

From: Dmitry Kasatkin <d.kasatkin@samsung.com>

commit 3034a146820c26fe6da66a45f6340fe87fe0983a upstream.

Empty files and missing xattrs do not guarantee that a file was
just created. This patch passes FILE_CREATED flag to IMA to
reliably identify new files.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
[bwh: Backported to 3.16: drop change to ima_fw_from_file()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3086,7 +3086,7 @@ opened:
error = open_check_o_direct(file);
if (error)
goto exit_fput;
- error = ima_file_check(file, op->acc_mode);
+ error = ima_file_check(file, op->acc_mode, *opened);
if (error)
goto exit_fput;

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -736,7 +736,7 @@ nfsd_open(struct svc_rqst *rqstp, struct
host_err = PTR_ERR(*filp);
*filp = NULL;
} else {
- host_err = ima_file_check(*filp, may_flags);
+ host_err = ima_file_check(*filp, may_flags, 0);

if (may_flags & NFSD_MAY_64BIT_COOKIE)
(*filp)->f_mode |= FMODE_64BITHASH;
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -15,7 +15,7 @@ struct linux_binprm;

#ifdef CONFIG_IMA
extern int ima_bprm_check(struct linux_binprm *bprm);
-extern int ima_file_check(struct file *file, int mask);
+extern int ima_file_check(struct file *file, int mask, int opened);
extern void ima_file_free(struct file *file);
extern int ima_file_mmap(struct file *file, unsigned long prot);
extern int ima_module_check(struct file *file);
@@ -26,7 +26,7 @@ static inline int ima_bprm_check(struct
return 0;
}

-static inline int ima_file_check(struct file *file, int mask)
+static inline int ima_file_check(struct file *file, int mask, int opened)
{
return 0;
}
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -176,7 +176,7 @@ void ima_delete_rules(void);
int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
- int xattr_len);
+ int xattr_len, int opened);
int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
@@ -192,7 +192,7 @@ static inline int ima_appraise_measureme
struct file *file,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
- int xattr_len)
+ int xattr_len, int opened)
{
return INTEGRITY_UNKNOWN;
}
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -175,7 +175,7 @@ int ima_read_xattr(struct dentry *dentry
int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
- int xattr_len)
+ int xattr_len, int opened)
{
static const char op[] = "appraise_data";
char *cause = "unknown";
@@ -195,7 +195,7 @@ int ima_appraise_measurement(int func, s

cause = "missing-hash";
status = INTEGRITY_NOLABEL;
- if (inode->i_size == 0) {
+ if (opened & FILE_CREATED) {
iint->flags |= IMA_NEW_FILE;
status = INTEGRITY_PASS;
}
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -161,7 +161,7 @@ void ima_file_free(struct file *file)
}

static int process_measurement(struct file *file, const char *filename,
- int mask, int function)
+ int mask, int function, int opened)
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint;
@@ -229,7 +229,7 @@ static int process_measurement(struct fi
xattr_value, xattr_len);
if (action & IMA_APPRAISE_SUBMASK)
rc = ima_appraise_measurement(_func, iint, file, pathname,
- xattr_value, xattr_len);
+ xattr_value, xattr_len, opened);
if (action & IMA_AUDIT)
ima_audit_measurement(iint, pathname);
kfree(pathbuf);
@@ -258,7 +258,7 @@ out:
int ima_file_mmap(struct file *file, unsigned long prot)
{
if (file && (prot & PROT_EXEC))
- return process_measurement(file, NULL, MAY_EXEC, MMAP_CHECK);
+ return process_measurement(file, NULL, MAY_EXEC, MMAP_CHECK, 0);
return 0;
}

@@ -280,7 +280,7 @@ int ima_bprm_check(struct linux_binprm *
return process_measurement(bprm->file,
(strcmp(bprm->filename, bprm->interp) == 0) ?
bprm->filename : bprm->interp,
- MAY_EXEC, BPRM_CHECK);
+ MAY_EXEC, BPRM_CHECK, 0);
}

/**
@@ -293,12 +293,12 @@ int ima_bprm_check(struct linux_binprm *
* On success return 0. On integrity appraisal error, assuming the file
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
*/
-int ima_file_check(struct file *file, int mask)
+int ima_file_check(struct file *file, int mask, int opened)
{
ima_rdwr_violation_check(file);
return process_measurement(file, NULL,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
- FILE_CHECK);
+ FILE_CHECK, opened);
}
EXPORT_SYMBOL_GPL(ima_file_check);

@@ -321,7 +321,7 @@ int ima_module_check(struct file *file)
#endif
return 0; /* We rely on module signature checking */
}
- return process_measurement(file, NULL, MAY_EXEC, MODULE_CHECK);
+ return process_measurement(file, NULL, MAY_EXEC, MODULE_CHECK, 0);
}

static int __init init_ima(void)