ima: pass filename to ima_rdwr_violation_check()

ima_rdwr_violation_check() retrieves the full path of a measured file by
calling ima_d_path(). If process_measurement() calls this function, it
reuses the pointer and passes it to the functions to measure/appraise/audit
an accessed file.

After commit bc15ed663e7e ("ima: fix ima_d_path() possible race with
rename"), ima_d_path() first tries to retrieve the full path by calling
d_absolute_path() and, if there is an error, copies the dentry name to the
buffer passed as argument.

However, ima_rdwr_violation_check() passes to ima_d_path() the pointer of a
local variable. process_measurement() might be reusing the pointer to an
area in the stack which may have been already overwritten after
ima_rdwr_violation_check() returned.

Correct this issue by passing to ima_rdwr_violation_check() the pointer of
a buffer declared in process_measurement().

Fixes: bc15ed663e7e ("ima: fix ima_d_path() possible race with rename")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index be1987e13c43b031ad99c591f38d3198d022331a..0abc7d0db90b96e16a2a0b06dba6bcc74fb66a53 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -84,10 +84,10 @@ static void ima_rdwr_violation_check(struct file *file,
                                     struct integrity_iint_cache *iint,
                                     int must_measure,
                                     char **pathbuf,
-                                    const char **pathname)
+                                    const char **pathname,
+                                    char *filename)
 {
        struct inode *inode = file_inode(file);
-       char filename[NAME_MAX];
        fmode_t mode = file->f_mode;
        bool send_tomtou = false, send_writers = false;
 
@@ -210,7 +210,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
 
        if (!rc && violation_check)
                ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
-                                        &pathbuf, &pathname);
+                                        &pathbuf, &pathname, filename);
 
        inode_unlock(inode);