From: Petr Štetiar Date: Thu, 2 Dec 2021 12:54:42 +0000 (+0100) Subject: libs/c-ares: fix domain hijacking CVE-2021-3672 X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=refs%2Fpull%2F17250%2Fhead;p=feed%2Fpackages.git libs/c-ares: fix domain hijacking CVE-2021-3672 Missing input validation of host names returned by Domain Name Servers in the c-ares library can lead to output of wrong hostnames (leading to Domain Hijacking). I've just taken patch from the advisory[1] and rebased it onto 1.15.0 version. 1. https://github.com/c-ares/c-ares/compare/809d5e8..44c009b.patch Fixes: CVE-2021-3672 Signed-off-by: Petr Štetiar --- diff --git a/libs/c-ares/Makefile b/libs/c-ares/Makefile index b2138461d1..83c460a8da 100644 --- a/libs/c-ares/Makefile +++ b/libs/c-ares/Makefile @@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=c-ares PKG_VERSION:=1.15.0 -PKG_RELEASE:=4 +PKG_RELEASE:=5 PKG_LICENSE:=MIT PKG_CPE_ID:=cpe:/a:c-ares_project:c-ares diff --git a/libs/c-ares/patches/0001-ares_expand_name-should-escape-more-characters.patch b/libs/c-ares/patches/0001-ares_expand_name-should-escape-more-characters.patch new file mode 100644 index 0000000000..3103ef6a18 --- /dev/null +++ b/libs/c-ares/patches/0001-ares_expand_name-should-escape-more-characters.patch @@ -0,0 +1,88 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: bradh352 +Date: Fri, 11 Jun 2021 11:27:45 -0400 +Subject: [PATCH] ares_expand_name() should escape more characters +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +RFC1035 5.1 specifies some reserved characters and escaping sequences +that are allowed to be specified. Expand the list of reserved characters +and also escape non-printable characters using the \DDD format as +specified in the RFC. + +Bug Reported By: philipp.jeitner@sit.fraunhofer.de +Fix By: Brad House (@bradh352) +[rebased onto 1.15.0] +Signed-off-by: Petr Å tetiar +--- + ares_expand_name.c | 41 ++++++++++++++++++++++++++++++++++++++--- + 1 file changed, 38 insertions(+), 3 deletions(-) + +diff --git a/ares_expand_name.c b/ares_expand_name.c +index 3a38e6737e93..8604543fc39d 100644 +--- a/ares_expand_name.c ++++ b/ares_expand_name.c +@@ -38,6 +38,26 @@ + static int name_length(const unsigned char *encoded, const unsigned char *abuf, + int alen); + ++/* Reserved characters for names that need to be escaped */ ++static int is_reservedch(int ch) ++{ ++ switch (ch) { ++ case '"': ++ case '.': ++ case ';': ++ case '\\': ++ case '(': ++ case ')': ++ case '@': ++ case '$': ++ return 1; ++ default: ++ break; ++ } ++ ++ return 0; ++} ++ + /* Expand an RFC1035-encoded domain name given by encoded. The + * containing message is given by abuf and alen. The result given by + * *s, which is set to a NUL-terminated allocated buffer. *enclen is +@@ -117,9 +137,18 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf, + p++; + while (len--) + { +- if (*p == '.' || *p == '\\') ++ if (!isprint(*p)) { ++ /* Output as \DDD for consistency with RFC1035 5.1 */ ++ *q++ = '\\'; ++ *q++ = '0' + *p / 100; ++ *q++ = '0' + (*p % 100) / 10; ++ *q++ = '0' + (*p % 10); ++ } else if (is_reservedch(*p)) { + *q++ = '\\'; +- *q++ = *p; ++ *q++ = *p; ++ } else { ++ *q++ = *p; ++ } + p++; + } + *q++ = '.'; +@@ -177,7 +206,13 @@ static int name_length(const unsigned char *encoded, const unsigned char *abuf, + encoded++; + while (offset--) + { +- n += (*encoded == '.' || *encoded == '\\') ? 2 : 1; ++ if (!isprint(*encoded)) { ++ n += 4; ++ } else if (is_reservedch(*encoded)) { ++ n += 2; ++ } else { ++ n += 1; ++ } + encoded++; + } + n++; diff --git a/libs/c-ares/patches/0002-ares_expand_name-fix-formatting-and-handling-of-root.patch b/libs/c-ares/patches/0002-ares_expand_name-fix-formatting-and-handling-of-root.patch new file mode 100644 index 0000000000..9ce08c5a20 --- /dev/null +++ b/libs/c-ares/patches/0002-ares_expand_name-fix-formatting-and-handling-of-root.patch @@ -0,0 +1,113 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: bradh352 +Date: Fri, 11 Jun 2021 12:39:24 -0400 +Subject: [PATCH] ares_expand_name(): fix formatting and handling of root name + response +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Fixes issue introduced in prior commit with formatting and handling +of parsing a root name response which should not be escaped. + +Fix By: Brad House +[rebased onto 1.15.0] +Signed-off-by: Petr Å tetiar +--- + ares_expand_name.c | 62 ++++++++++++++++++++++++++++++---------------- + 1 file changed, 40 insertions(+), 22 deletions(-) + +diff --git a/ares_expand_name.c b/ares_expand_name.c +index 8604543fc39d..f89ee3f7a602 100644 +--- a/ares_expand_name.c ++++ b/ares_expand_name.c +@@ -133,27 +133,37 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf, + } + else + { +- len = *p; ++ int name_len = *p; ++ len = name_len; + p++; ++ + while (len--) + { +- if (!isprint(*p)) { +- /* Output as \DDD for consistency with RFC1035 5.1 */ +- *q++ = '\\'; +- *q++ = '0' + *p / 100; +- *q++ = '0' + (*p % 100) / 10; +- *q++ = '0' + (*p % 10); +- } else if (is_reservedch(*p)) { +- *q++ = '\\'; +- *q++ = *p; +- } else { +- *q++ = *p; +- } ++ /* Output as \DDD for consistency with RFC1035 5.1, except ++ * for the special case of a root name response */ ++ if (!isprint(*p) && !(name_len == 1 && *p == 0)) ++ { ++ ++ *q++ = '\\'; ++ *q++ = '0' + *p / 100; ++ *q++ = '0' + (*p % 100) / 10; ++ *q++ = '0' + (*p % 10); ++ } ++ else if (is_reservedch(*p)) ++ { ++ *q++ = '\\'; ++ *q++ = *p; ++ } ++ else ++ { ++ *q++ = *p; ++ } + p++; + } + *q++ = '.'; + } +- } ++ } ++ + if (!indir) + *enclen = aresx_uztosl(p + 1U - encoded); + +@@ -200,21 +210,29 @@ static int name_length(const unsigned char *encoded, const unsigned char *abuf, + } + else if (top == 0x00) + { +- offset = *encoded; ++ int name_len = *encoded; ++ offset = name_len; + if (encoded + offset + 1 >= abuf + alen) + return -1; + encoded++; ++ + while (offset--) + { +- if (!isprint(*encoded)) { +- n += 4; +- } else if (is_reservedch(*encoded)) { +- n += 2; +- } else { +- n += 1; +- } ++ if (!isprint(*encoded) && !(name_len == 1 && *encoded == 0)) ++ { ++ n += 4; ++ } ++ else if (is_reservedch(*encoded)) ++ { ++ n += 2; ++ } ++ else ++ { ++ n += 1; ++ } + encoded++; + } ++ + n++; + } + else