In the Linux kernel, the following vulnerability has been resolved: ima: Check for ERR_PTR from dentry_path() in validate_hash_algo() dent

In the Linux kernel, the following vulnerability has been resolved:

ima: Check for ERR_PTR from dentry_path() in validate_hash_algo()

dentry_path() returns ERR_PTR(-ENAMETOOLONG) when the path exceeds the
buffer. validate_hash_algo() passes the result straight to
integrity_audit_msg() without checking. ERR_PTR is not NULL, so
integrity_audit_message() sees a valid pointer and calls strlen() on
it, which faults:

 1BUG: unable to handle page fault for address: ffffffffffffffdc
 2RIP: 0010:strlen+0x30/0xa0
 3Call Trace:
 4 audit_log_untrustedstring+0x19/0x30
 5 integrity_audit_message+0x366/0x4f0
 6 ima_inode_setxattr+0x512/0x5f0

Check for IS_ERR() and use NULL instead, which makes the audit message
skip the name= field instead of crashing.