6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bradley Morgan commit 8861f6d5c0678a7c5089c7b272509fc5931b8437 upstream. 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: BUG: unable to handle page fault for address: ffffffffffffffdc RIP: 0010:strlen+0x30/0xa0 Call Trace: audit_log_untrustedstring+0x19/0x30 integrity_audit_message+0x366/0x4f0 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. Fixes: 4f2946aa0c45 ("IMA: introduce a new policy option func=SETXATTR_CHECK") Cc: stable@vger.kernel.org Reported-by: syzbot+5ebeb3089ea6439c37be@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/6a8f89e5.1d9ded08.62e62.00bf.GAE@google.com/ Signed-off-by: Bradley Morgan Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman --- security/integrity/ima/ima_appraise.c | 2 ++ 1 file changed, 2 insertions(+) --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -777,6 +777,8 @@ static int validate_hash_algo(struct den return -EACCES; path = dentry_path(dentry, pathbuf, PATH_MAX); + if (IS_ERR(path)) + path = NULL; integrity_audit_msg(AUDIT_INTEGRITY_DATA, d_inode(dentry), path, "set_data", errmsg, -EACCES, 0);