From: Daniel Thompson <daniel.thompson@linaro.org>
To: Jason Wessel <jason.wessel@windriver.com>,
Douglas Anderson <dianders@chromium.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>,
kgdb-bugreport@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: [PATCH] kdb: Fix the putarea helper function
Date: Fri, 28 Jan 2022 14:40:55 +0000 [thread overview]
Message-ID: <20220128144055.207267-1-daniel.thompson@linaro.org> (raw)
Currently kdb_putarea_size() uses copy_from_kernel_nofault() to write *to*
arbitrary kernel memory. This is obviously wrong and means the memory
modify ('mm') command is a serious risk to debugger stability: if we poke
to a bad address we'll double-fault and lose our debug session.
Fix this the (very) obvious way.
Note that there are two Fixes: tags because the API was renamed and this
patch will only trivially backport as far as the rename (and this is
probably enough). Nevertheless Christoph's rename did not introduce this
problem so I wanted to record that!
Fixes: fe557319aa06 ("maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault")
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
---
kernel/debug/kdb/kdb_support.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
index df2bface866ef..85cb51c4a17e6 100644
--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -291,7 +291,7 @@ int kdb_getarea_size(void *res, unsigned long addr, size_t size)
*/
int kdb_putarea_size(unsigned long addr, void *res, size_t size)
{
- int ret = copy_from_kernel_nofault((char *)addr, (char *)res, size);
+ int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
if (ret) {
if (!KDB_STATE(SUPPRESS)) {
kdb_func_printf("Bad address 0x%lx\n", addr);
base-commit: e783362eb54cd99b2cac8b3a9aeac942e6f6ac07
--
2.34.1
next reply other threads:[~2022-01-28 14:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 14:40 Daniel Thompson [this message]
2022-01-28 22:24 ` [PATCH] kdb: Fix the putarea helper function Doug Anderson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220128144055.207267-1-daniel.thompson@linaro.org \
--to=daniel.thompson@linaro.org \
--cc=dianders@chromium.org \
--cc=jason.wessel@windriver.com \
--cc=kgdb-bugreport@lists.sourceforge.net \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.