From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: kwolf@redhat.com, peter.maydell@linaro.org
Subject: [RFC PATCH] ide: atapi: assert that the buffer pointer is in range
Date: Tue, 1 Dec 2020 13:09:26 +0100 [thread overview]
Message-ID: <20201201120926.56559-1-pbonzini@redhat.com> (raw)
A case was reported where s->io_buffer_index can be out of range.
The report skimped on the details but it seems to be triggered
by s->lba == -1 on the READ/READ CD paths (e.g. by sending an
ATAPI command with LBA = 0xFFFFFFFF). For now paper over it
with assertions. The first one ensures that there is no overflow
when incrementing s->io_buffer_index, the second checks for the
buffer overrun.
Note that the buffer overrun is only a read, so I am not sure
if the assertion failure is actually less harmful than the overrun.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/ide/atapi.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
index 14a2b0bb2f..e79157863f 100644
--- a/hw/ide/atapi.c
+++ b/hw/ide/atapi.c
@@ -276,6 +276,8 @@ void ide_atapi_cmd_reply_end(IDEState *s)
s->packet_transfer_size -= size;
s->elementary_transfer_size -= size;
s->io_buffer_index += size;
+ assert(size <= s->io_buffer_total_len);
+ assert(s->io_buffer_index <= s->io_buffer_total_len);
/* Some adapters process PIO data right away. In that case, we need
* to avoid mutual recursion between ide_transfer_start
--
2.28.0
next reply other threads:[~2020-12-01 12:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 12:09 Paolo Bonzini [this message]
2020-12-01 15:17 ` [RFC PATCH] ide: atapi: assert that the buffer pointer is in range Kevin Wolf
2020-12-01 16:20 ` Peter Maydell
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=20201201120926.56559-1-pbonzini@redhat.com \
--to=pbonzini@redhat.com \
--cc=kwolf@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).