lkml.org 
[lkml]   [2023]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectCoverity: console_prepend_dropped(): Memory - corruptions
Hello!

This is an experimental semi-automated report about issues detected by
Coverity from a scan of next-20230113 as part of the linux-next scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by commits:

Wed Jan 11 15:35:11 2023 +0100
c4fcc617e148 ("printk: introduce console_prepend_dropped() for dropped messages")

Coverity reported the following:

*** CID 1530570: Memory - corruptions (OVERRUN)
kernel/printk/printk.c:2738 in console_prepend_dropped()
2732 /* Truncate the message, but keep it terminated. */
2733 pmsg->outbuf_len = outbuf_sz - (len + 1);
2734 outbuf[pmsg->outbuf_len] = 0;
2735 }
2736
2737 memmove(outbuf + len, outbuf, pmsg->outbuf_len + 1);
vvv CID 1530570: Memory - corruptions (OVERRUN)
vvv Overrunning buffer pointed to by "scratchbuf" of 1024 bytes by passing it to a function which accesses it at byte offset 1998 using argument "len" (which evaluates to 1999). [Note: The source code implementation of the function has been overridden by a builtin model.]
2738 memcpy(outbuf, scratchbuf, len);
2739 pmsg->outbuf_len += len;
2740 }
2741 #else
2742 #define console_prepend_dropped(pmsg, dropped)
2743 #endif /* CONFIG_PRINTK */

If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1530570 ("Memory - corruptions")
Fixes: c4fcc617e148 ("printk: introduce console_prepend_dropped() for dropped messages")

Thanks for your attention!

Human notes from Kees:

I'm not sure how it got 1998, but I do see that snprintf() should
probably be scnprintf(), otherwise "len" might be a lie (i.e. it'll hold
what it WANTED to write, rather than what it actually wrote).

--
Coverity-bot

\
 
 \ /
  Last update: 2023-03-26 23:41    [W:0.039 / U:3.844 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site