From 1c7d6584a7811b7785ae5c1e378f14b5ba0971cf Mon Sep 17 00:00:00 2001 From: takeshi_hoshina Date: Mon, 2 Nov 2020 11:07:33 +0900 Subject: basesystem-jj recipes --- .../qemu/qemu/CVE-2020-10761.patch | 150 +++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 external/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-10761.patch (limited to 'external/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-10761.patch') diff --git a/external/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-10761.patch b/external/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-10761.patch new file mode 100644 index 00000000..e5e336a2 --- /dev/null +++ b/external/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-10761.patch @@ -0,0 +1,150 @@ +From 5c4fe018c025740fef4a0a4421e8162db0c3eefd Mon Sep 17 00:00:00 2001 +From: Eric Blake +Date: Mon, 8 Jun 2020 13:26:37 -0500 +Subject: [PATCH] nbd/server: Avoid long error message assertions + CVE-2020-10761 + +Ever since commit 36683283 (v2.8), the server code asserts that error +strings sent to the client are well-formed per the protocol by not +exceeding the maximum string length of 4096. At the time the server +first started sending error messages, the assertion could not be +triggered, because messages were completely under our control. +However, over the years, we have added latent scenarios where a client +could trigger the server to attempt an error message that would +include the client's information if it passed other checks first: + +- requesting NBD_OPT_INFO/GO on an export name that is not present + (commit 0cfae925 in v2.12 echoes the name) + +- requesting NBD_OPT_LIST/SET_META_CONTEXT on an export name that is + not present (commit e7b1948d in v2.12 echoes the name) + +At the time, those were still safe because we flagged names larger +than 256 bytes with a different message; but that changed in commit +93676c88 (v4.2) when we raised the name limit to 4096 to match the NBD +string limit. (That commit also failed to change the magic number +4096 in nbd_negotiate_send_rep_err to the just-introduced named +constant.) So with that commit, long client names appended to server +text can now trigger the assertion, and thus be used as a denial of +service attack against a server. As a mitigating factor, if the +server requires TLS, the client cannot trigger the problematic paths +unless it first supplies TLS credentials, and such trusted clients are +less likely to try to intentionally crash the server. + +We may later want to further sanitize the user-supplied strings we +place into our error messages, such as scrubbing out control +characters, but that is less important to the CVE fix, so it can be a +later patch to the new nbd_sanitize_name. + +Consideration was given to changing the assertion in +nbd_negotiate_send_rep_verr to instead merely log a server error and +truncate the message, to avoid leaving a latent path that could +trigger a future CVE DoS on any new error message. However, this +merely complicates the code for something that is already (correctly) +flagging coding errors, and now that we are aware of the long message +pitfall, we are less likely to introduce such errors in the future, +which would make such error handling dead code. + +Reported-by: Xueqiang Wei +CC: qemu-stable@nongnu.org +Fixes: https://bugzilla.redhat.com/1843684 CVE-2020-10761 +Fixes: 93676c88d7 +Signed-off-by: Eric Blake +Message-Id: <20200610163741.3745251-2-eblake@redhat.com> +Reviewed-by: Vladimir Sementsov-Ogievskiy + +Upstream-Status: Backport [https://github.com/qemu/qemu/commit/5c4fe018c025740fef4a0a4421e8162db0c3eefd] +CVE: CVE-2020-10761 +Signed-off-by: Chee Yang Lee +--- + nbd/server.c | 23 ++++++++++++++++++++--- + tests/qemu-iotests/143 | 4 ++++ + tests/qemu-iotests/143.out | 2 ++ + 3 files changed, 26 insertions(+), 3 deletions(-) + +diff --git a/nbd/server.c b/nbd/server.c +index 02b1ed08014..20754e9ebc3 100644 +--- a/nbd/server.c ++++ b/nbd/server.c +@@ -217,7 +217,7 @@ nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, + + msg = g_strdup_vprintf(fmt, va); + len = strlen(msg); +- assert(len < 4096); ++ assert(len < NBD_MAX_STRING_SIZE); + trace_nbd_negotiate_send_rep_err(msg); + ret = nbd_negotiate_send_rep_len(client, type, len, errp); + if (ret < 0) { +@@ -231,6 +231,19 @@ nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, + return 0; + } + ++/* ++ * Return a malloc'd copy of @name suitable for use in an error reply. ++ */ ++static char * ++nbd_sanitize_name(const char *name) ++{ ++ if (strnlen(name, 80) < 80) { ++ return g_strdup(name); ++ } ++ /* XXX Should we also try to sanitize any control characters? */ ++ return g_strdup_printf("%.80s...", name); ++} ++ + /* Send an error reply. + * Return -errno on error, 0 on success. */ + static int GCC_FMT_ATTR(4, 5) +@@ -595,9 +608,11 @@ static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) + + exp = nbd_export_find(name); + if (!exp) { ++ g_autofree char *sane_name = nbd_sanitize_name(name); ++ + return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, + errp, "export '%s' not present", +- name); ++ sane_name); + } + + /* Don't bother sending NBD_INFO_NAME unless client requested it */ +@@ -995,8 +1010,10 @@ static int nbd_negotiate_meta_queries(NBDClient *client, + + meta->exp = nbd_export_find(export_name); + if (meta->exp == NULL) { ++ g_autofree char *sane_name = nbd_sanitize_name(export_name); ++ + return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, +- "export '%s' not present", export_name); ++ "export '%s' not present", sane_name); + } + + ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp); +diff --git a/tests/qemu-iotests/143 b/tests/qemu-iotests/143 +index f649b361950..d2349903b1b 100755 +--- a/tests/qemu-iotests/143 ++++ b/tests/qemu-iotests/143 +@@ -58,6 +58,10 @@ _send_qemu_cmd $QEMU_HANDLE \ + $QEMU_IO_PROG -f raw -c quit \ + "nbd+unix:///no_such_export?socket=$SOCK_DIR/nbd" 2>&1 \ + | _filter_qemu_io | _filter_nbd ++# Likewise, with longest possible name permitted in NBD protocol ++$QEMU_IO_PROG -f raw -c quit \ ++ "nbd+unix:///$(printf %4096d 1 | tr ' ' a)?socket=$SOCK_DIR/nbd" 2>&1 \ ++ | _filter_qemu_io | _filter_nbd | sed 's/aaaa*aa/aa--aa/' + + _send_qemu_cmd $QEMU_HANDLE \ + "{ 'execute': 'quit' }" \ +diff --git a/tests/qemu-iotests/143.out b/tests/qemu-iotests/143.out +index 1f4001c6013..fc9c0a761fa 100644 +--- a/tests/qemu-iotests/143.out ++++ b/tests/qemu-iotests/143.out +@@ -5,6 +5,8 @@ QA output created by 143 + {"return": {}} + qemu-io: can't open device nbd+unix:///no_such_export?socket=SOCK_DIR/nbd: Requested export not available + server reported: export 'no_such_export' not present ++qemu-io: can't open device nbd+unix:///aa--aa1?socket=SOCK_DIR/nbd: Requested export not available ++server reported: export 'aa--aa...' not present + { 'execute': 'quit' } + {"return": {}} + {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "SHUTDOWN", "data": {"guest": false, "reason": "host-qmp-quit"}} -- cgit 1.2.3-korg