From cf118077cd4f909a7ad68e6efdc07fe93f63b650 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Petr=20=C5=A0tetiar?= Date: Thu, 20 Feb 2020 09:03:54 +0100 Subject: [PATCH] ppp: backport security fixes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 8d45443bb5c9 pppd: Ignore received EAP messages when not doing EAP 8d7970b8f3db pppd: Fix bounds check in EAP code 858976b1fc31 radius: Prevent buffer overflow in rc_mksid() Signed-off-by: Petr Å tetiar (cherry picked from commit 215598fd03899c19a9cd26266221269dd5ec8cee) Fixes: CVE-2020-8597 Signed-off-by: Jo-Philipp Wich --- package/network/services/ppp/Makefile | 2 +- ...-Prevent-buffer-overflow-in-rc_mksid.patch | 30 +++++++++ ...01-pppd-Fix-bounds-check-in-EAP-code.patch | 37 +++++++++++ ...ived-EAP-messages-when-not-doing-EAP.patch | 61 +++++++++++++++++++ 4 files changed, 129 insertions(+), 1 deletion(-) create mode 100644 package/network/services/ppp/patches/700-radius-Prevent-buffer-overflow-in-rc_mksid.patch create mode 100644 package/network/services/ppp/patches/701-pppd-Fix-bounds-check-in-EAP-code.patch create mode 100644 package/network/services/ppp/patches/702-pppd-Ignore-received-EAP-messages-when-not-doing-EAP.patch diff --git a/package/network/services/ppp/Makefile b/package/network/services/ppp/Makefile index 10e7656ea4..d21d1e0438 100644 --- a/package/network/services/ppp/Makefile +++ b/package/network/services/ppp/Makefile @@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk include $(INCLUDE_DIR)/kernel.mk PKG_NAME:=ppp -PKG_RELEASE:=2 +PKG_RELEASE:=3 PKG_SOURCE_PROTO:=git PKG_SOURCE_URL:=https://github.com/paulusmack/ppp diff --git a/package/network/services/ppp/patches/700-radius-Prevent-buffer-overflow-in-rc_mksid.patch b/package/network/services/ppp/patches/700-radius-Prevent-buffer-overflow-in-rc_mksid.patch new file mode 100644 index 0000000000..1c5722e6dd --- /dev/null +++ b/package/network/services/ppp/patches/700-radius-Prevent-buffer-overflow-in-rc_mksid.patch @@ -0,0 +1,30 @@ +From 858976b1fc3107f1261aae337831959b511b83c2 Mon Sep 17 00:00:00 2001 +From: Paul Mackerras +Date: Sat, 4 Jan 2020 12:01:32 +1100 +Subject: [PATCH] radius: Prevent buffer overflow in rc_mksid() + +On some systems getpid() can return a value greater than 65535. +Increase the size of buf[] to allow for this, and use slprintf() +to make sure we never overflow it. + +Signed-off-by: Paul Mackerras +--- + pppd/plugins/radius/util.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/pppd/plugins/radius/util.c b/pppd/plugins/radius/util.c +index 6f976a712951..740131e8377c 100644 +--- a/pppd/plugins/radius/util.c ++++ b/pppd/plugins/radius/util.c +@@ -73,9 +73,9 @@ void rc_mdelay(int msecs) + char * + rc_mksid (void) + { +- static char buf[15]; ++ static char buf[32]; + static unsigned short int cnt = 0; +- sprintf (buf, "%08lX%04X%02hX", ++ slprintf(buf, sizeof(buf), "%08lX%04X%02hX", + (unsigned long int) time (NULL), + (unsigned int) getpid (), + cnt & 0xFF); diff --git a/package/network/services/ppp/patches/701-pppd-Fix-bounds-check-in-EAP-code.patch b/package/network/services/ppp/patches/701-pppd-Fix-bounds-check-in-EAP-code.patch new file mode 100644 index 0000000000..c2ca9729ec --- /dev/null +++ b/package/network/services/ppp/patches/701-pppd-Fix-bounds-check-in-EAP-code.patch @@ -0,0 +1,37 @@ +From 8d7970b8f3db727fe798b65f3377fe6787575426 Mon Sep 17 00:00:00 2001 +From: Paul Mackerras +Date: Mon, 3 Feb 2020 15:53:28 +1100 +Subject: [PATCH] pppd: Fix bounds check in EAP code + +Given that we have just checked vallen < len, it can never be the case +that vallen >= len + sizeof(rhostname). This fixes the check so we +actually avoid overflowing the rhostname array. + +Reported-by: Ilja Van Sprundel +Signed-off-by: Paul Mackerras +--- + pppd/eap.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/pppd/eap.c b/pppd/eap.c +index 94407f56a336..1b93db01aebd 100644 +--- a/pppd/eap.c ++++ b/pppd/eap.c +@@ -1420,7 +1420,7 @@ int len; + } + + /* Not so likely to happen. */ +- if (vallen >= len + sizeof (rhostname)) { ++ if (len - vallen >= sizeof (rhostname)) { + dbglog("EAP: trimming really long peer name down"); + BCOPY(inp + vallen, rhostname, sizeof (rhostname) - 1); + rhostname[sizeof (rhostname) - 1] = '\0'; +@@ -1846,7 +1846,7 @@ int len; + } + + /* Not so likely to happen. */ +- if (vallen >= len + sizeof (rhostname)) { ++ if (len - vallen >= sizeof (rhostname)) { + dbglog("EAP: trimming really long peer name down"); + BCOPY(inp + vallen, rhostname, sizeof (rhostname) - 1); + rhostname[sizeof (rhostname) - 1] = '\0'; diff --git a/package/network/services/ppp/patches/702-pppd-Ignore-received-EAP-messages-when-not-doing-EAP.patch b/package/network/services/ppp/patches/702-pppd-Ignore-received-EAP-messages-when-not-doing-EAP.patch new file mode 100644 index 0000000000..7286d81a56 --- /dev/null +++ b/package/network/services/ppp/patches/702-pppd-Ignore-received-EAP-messages-when-not-doing-EAP.patch @@ -0,0 +1,61 @@ +From 8d45443bb5c9372b4c6a362ba2f443d41c5636af Mon Sep 17 00:00:00 2001 +From: Paul Mackerras +Date: Mon, 3 Feb 2020 16:31:42 +1100 +Subject: [PATCH] pppd: Ignore received EAP messages when not doing EAP + +This adds some basic checks to the subroutines of eap_input to check +that we have requested or agreed to doing EAP authentication before +doing any processing on the received packet. The motivation is to +make it harder for a malicious peer to disrupt the operation of pppd +by sending unsolicited EAP packets. Note that eap_success() already +has a check that the EAP client state is reasonable, and does nothing +(apart from possibly printing a debug message) if not. + +Signed-off-by: Paul Mackerras +--- + pppd/eap.c | 18 ++++++++++++++++++ + 1 file changed, 18 insertions(+) + +diff --git a/pppd/eap.c b/pppd/eap.c +index 1b93db01aebd..082e95343120 100644 +--- a/pppd/eap.c ++++ b/pppd/eap.c +@@ -1328,6 +1328,12 @@ int len; + int fd; + #endif /* USE_SRP */ + ++ /* ++ * Ignore requests if we're not open ++ */ ++ if (esp->es_client.ea_state <= eapClosed) ++ return; ++ + /* + * Note: we update es_client.ea_id *only if* a Response + * message is being generated. Otherwise, we leave it the +@@ -1736,6 +1742,12 @@ int len; + u_char dig[SHA_DIGESTSIZE]; + #endif /* USE_SRP */ + ++ /* ++ * Ignore responses if we're not open ++ */ ++ if (esp->es_server.ea_state <= eapClosed) ++ return; ++ + if (esp->es_server.ea_id != id) { + dbglog("EAP: discarding Response %d; expected ID %d", id, + esp->es_server.ea_id); +@@ -2047,6 +2059,12 @@ u_char *inp; + int id; + int len; + { ++ /* ++ * Ignore failure messages if we're not open ++ */ ++ if (esp->es_client.ea_state <= eapClosed) ++ return; ++ + if (!eap_client_active(esp)) { + dbglog("EAP unexpected failure message in state %s (%d)", + eap_state_name(esp->es_client.ea_state), -- 2.25.1