This is a note to let you know that I've just added the patch titled
scsi: core: Fix legacy /proc parsing buffer overflow
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-core-fix-legacy-proc-parsing-buffer-overflow.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9426d3cef5000824e5f24f80ed5f42fb935f2488 Mon Sep 17 00:00:00 2001
From: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
Date: Mon, 24 Jul 2023 14:25:40 -0400
Subject: scsi: core: Fix legacy /proc parsing buffer overflow
From: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
commit 9426d3cef5000824e5f24f80ed5f42fb935f2488 upstream.
(lightly modified commit message mostly by Linus Torvalds)
The parsing code for /proc/scsi/scsi is disgusting and broken. We should
have just used 'sscanf()' or something simple like that, but the logic may
actually predate our kernel sscanf library routine for all I know. It
certainly predates both git and BK histories.
And we can't change it to be something sane like that now, because the
string matching at the start is done case-insensitively, and the separator
parsing between numbers isn't done at all, so *any* separator will work,
including a possible terminating NUL character.
This interface is root-only, and entirely for legacy use, so there is
absolutely no point in trying to tighten up the parsing. Because any
separator has traditionally worked, it's entirely possible that people have
used random characters rather than the suggested space.
So don't bother to try to pretty it up, and let's just make a minimal patch
that can be back-ported and we can forget about this whole sorry thing for
another two decades.
Just make it at least not read past the end of the supplied data.
Link: https://lore.kernel.org/linux-scsi/b570f5fe-cb7c-863a-6ed9-f6774c219b88@xxxxxxxxxxxxxxx/
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Martin K Petersen <martin.petersen@xxxxxxxxxx>
Cc: James Bottomley <jejb@xxxxxxxxxxxxx>
Cc: Willy Tarreau <w@xxxxxx>
Cc: stable@xxxxxxxxxx
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
Signed-off-by: Martin K Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_proc.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -311,7 +311,7 @@ static ssize_t proc_scsi_write(struct fi
size_t length, loff_t *ppos)
{
int host, channel, id, lun;
- char *buffer, *p;
+ char *buffer, *end, *p;
int err;
if (!buf || length > PAGE_SIZE)
@@ -326,10 +326,14 @@ static ssize_t proc_scsi_write(struct fi
goto out;
err = -EINVAL;
- if (length < PAGE_SIZE)
- buffer[length] = '\0';
- else if (buffer[PAGE_SIZE-1])
- goto out;
+ if (length < PAGE_SIZE) {
+ end = buffer + length;
+ *end = '\0';
+ } else {
+ end = buffer + PAGE_SIZE - 1;
+ if (*end)
+ goto out;
+ }
/*
* Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
@@ -338,10 +342,10 @@ static ssize_t proc_scsi_write(struct fi
if (!strncmp("scsi add-single-device", buffer, 22)) {
p = buffer + 23;
- host = simple_strtoul(p, &p, 0);
- channel = simple_strtoul(p + 1, &p, 0);
- id = simple_strtoul(p + 1, &p, 0);
- lun = simple_strtoul(p + 1, &p, 0);
+ host = (p < end) ? simple_strtoul(p, &p, 0) : 0;
+ channel = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
+ id = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
+ lun = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
err = scsi_add_single_device(host, channel, id, lun);
@@ -352,10 +356,10 @@ static ssize_t proc_scsi_write(struct fi
} else if (!strncmp("scsi remove-single-device", buffer, 25)) {
p = buffer + 26;
- host = simple_strtoul(p, &p, 0);
- channel = simple_strtoul(p + 1, &p, 0);
- id = simple_strtoul(p + 1, &p, 0);
- lun = simple_strtoul(p + 1, &p, 0);
+ host = (p < end) ? simple_strtoul(p, &p, 0) : 0;
+ channel = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
+ id = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
+ lun = (p + 1 < end) ? simple_strtoul(p + 1, &p, 0) : 0;
err = scsi_remove_single_device(host, channel, id, lun);
}
Patches currently in stable-queue which might be from tonyb@xxxxxxxxxxxxxxx are
queue-5.10/scsi-core-fix-legacy-proc-parsing-buffer-overflow.patch
