linux-kernel - RE: [PATCH] FS: Fixed buffer overflow issue in seq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Tue, 19 Nov 2013 21:22:58 +0000
From:	"Charley (Hao Chuan) Chu" <charley.chu@...adcom.com>
To:	"Linus Torvalds" <torvalds@...ux-foundation.org>,
	"Al Viro" <viro@...iv.linux.org.uk>
cc:	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] FS: Fixed buffer overflow issue in seq_read()

> m->from is a red herring - it's not even looked at if m->count is 0.  

Then, shall the initialization here be removed too?

@@ -90,7 +90,7 @@ static int traverse(struct seq_file *m, loff_t offset)
 
        m->version = 0;
        index = 0;
-       m->count = m->from = 0;
+       m->count = 0;
        if (!offset) {
                m->index = index;
                return 0;

> What do you think about then just abstracing out that now common sequence 
> of re-allocating a larger buffer, while clearing m->count?

Following code is duplicated (slightly different) in both seq_read() and seq_lseek().
It would be nice to have them consolidated in traverse().

                while ((err = traverse(m, *ppos)) == -EAGAIN)
                        ;   
                if (err) {
                        /* With prejudice... */
                        m->read_pos = 0;
                        m->version = 0;
                        m->index = 0;
                        m->count = 0;
                        goto Done;
                } else {
                        m->read_pos = *ppos;
                }   

Thanks,
Charley

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/