aboutsummaryrefslogtreecommitdiff
path: root/gnu/packages/patches/qemu-CVE-2017-15119.patch
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/packages/patches/qemu-CVE-2017-15119.patch')
-rw-r--r--gnu/packages/patches/qemu-CVE-2017-15119.patch68
1 files changed, 68 insertions, 0 deletions
diff --git a/gnu/packages/patches/qemu-CVE-2017-15119.patch b/gnu/packages/patches/qemu-CVE-2017-15119.patch
new file mode 100644
index 0000000000..6265ecf8d6
--- /dev/null
+++ b/gnu/packages/patches/qemu-CVE-2017-15119.patch
@@ -0,0 +1,68 @@
+Fix CVE-2017-15119:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-15119
+https://bugzilla.redhat.com/show_bug.cgi?id=1516925
+
+Patch copied from upstream source repository:
+
+https://git.qemu.org/?p=qemu.git;a=commitdiff;h=fdad35ef6c5839d50dfc14073364ac893afebc30
+
+From fdad35ef6c5839d50dfc14073364ac893afebc30 Mon Sep 17 00:00:00 2001
+From: Eric Blake <eblake@redhat.com>
+Date: Wed, 22 Nov 2017 16:25:16 -0600
+Subject: [PATCH] nbd/server: CVE-2017-15119 Reject options larger than 32M
+
+The NBD spec gives us permission to abruptly disconnect on clients
+that send outrageously large option requests, rather than having
+to spend the time reading to the end of the option. No real
+option request requires that much data anyways; and meanwhile, we
+already have the practice of abruptly dropping the connection on
+any client that sends NBD_CMD_WRITE with a payload larger than 32M.
+
+For comparison, nbdkit drops the connection on any request with
+more than 4096 bytes; however, that limit is probably too low
+(as the NBD spec states an export name can theoretically be up
+to 4096 bytes, which means a valid NBD_OPT_INFO could be even
+longer) - even if qemu doesn't permit exports longer than 256
+bytes.
+
+It could be argued that a malicious client trying to get us to
+read nearly 4G of data on a bad request is a form of denial of
+service. In particular, if the server requires TLS, but a client
+that does not know the TLS credentials sends any option (other
+than NBD_OPT_STARTTLS or NBD_OPT_EXPORT_NAME) with a stated
+payload of nearly 4G, then the server was keeping the connection
+alive trying to read all the payload, tying up resources that it
+would rather be spending on a client that can get past the TLS
+handshake. Hence, this warranted a CVE.
+
+Present since at least 2.5 when handling known options, and made
+worse in 2.6 when fixing support for NBD_FLAG_C_FIXED_NEWSTYLE
+to handle unknown options.
+
+CC: qemu-stable@nongnu.org
+Signed-off-by: Eric Blake <eblake@redhat.com>
+---
+ nbd/server.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/nbd/server.c b/nbd/server.c
+index 7d6801b427..a81801e3bc 100644
+--- a/nbd/server.c
++++ b/nbd/server.c
+@@ -673,6 +673,12 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
+ }
+ length = be32_to_cpu(length);
+
++ if (length > NBD_MAX_BUFFER_SIZE) {
++ error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)",
++ length, NBD_MAX_BUFFER_SIZE);
++ return -EINVAL;
++ }
++
+ trace_nbd_negotiate_options_check_option(option,
+ nbd_opt_lookup(option));
+ if (client->tlscreds &&
+--
+2.15.0
+