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fix CVE-2022-4904

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This commit is contained in:
xingwei 2023-02-10 08:51:59 +00:00
parent 7173b08e3e
commit b3933e836b
2 changed files with 70 additions and 1 deletions
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62
backport-add-str-len-check-in-config_sortlist-to-avoid-stack-overflow.patch Normal file
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@ -0,0 +1,62 @@
From ac596026e77244481fd68736ae7f15855803a08a Mon Sep 17 00:00:00 2001
From: hopper-vul <hopper.vul@gmail.com>
Date: Tue, 13 Dec 2022 19:54:21 +0800
Subject: [PATCH] Add str len check in config_sortlist to avoid stack overflow
In ares_set_sortlist, it calls config_sortlist(..., sortstr) to parse
the input str and initialize a sortlist configuration.
However, ares_set_sortlist has not any checks about the validity of the input str.
It is very easy to create an arbitrary length stack overflow with the unchecked
`memcpy(ipbuf, str, q-str);` and `memcpy(ipbufpfx, str, q-str);`
statements in the config_sortlist call, which could potentially cause severe
security impact in practical programs.
This commit add necessary check for `ipbuf` and `ipbufpfx` which avoid the
potential stack overflows.
fixes #496
Signed-off-by: hopper-vul <hopper.vul@gmail.com>
---
src/lib/ares_init.c | 4 ++++
test/ares-test-init.cc | 2 ++
2 files changed, 6 insertions(+)
diff --git a/src/lib/ares_init.c b/src/lib/ares_init.c
index de5d86c..d5858f6 100644
--- a/src/lib/ares_init.c
+++ b/src/lib/ares_init.c
@@ -2243,6 +2243,8 @@ static int config_sortlist(struct apattern **sortlist, int *nsort,
q = str;
while (*q && *q != '/' && *q != ';' && !ISSPACE(*q))
q++;
+ if (q-str >= 16)
+ return ARES_EBADSTR;
memcpy(ipbuf, str, q-str);
ipbuf[q-str] = '\0';
/* Find the prefix */
@@ -2251,6 +2253,8 @@ static int config_sortlist(struct apattern **sortlist, int *nsort,
const char *str2 = q+1;
while (*q && *q != ';' && !ISSPACE(*q))
q++;
+ if (q-str >= 32)
+ return ARES_EBADSTR;
memcpy(ipbufpfx, str, q-str);
ipbufpfx[q-str] = '\0';
str = str2;
diff --git a/test/ares-test-init.cc b/test/ares-test-init.cc
index ff6c6c6..c3cb948 100644
--- a/test/ares-test-init.cc
+++ b/test/ares-test-init.cc
@@ -270,6 +270,8 @@ TEST_F(DefaultChannelTest, SetAddresses) {
TEST_F(DefaultChannelTest, SetSortlistFailures) {
EXPECT_EQ(ARES_ENODATA, ares_set_sortlist(nullptr, "1.2.3.4"));
+ EXPECT_EQ(ARES_EBADSTR, ares_set_sortlist(channel_, "111.111.111.111*/16"));
+ EXPECT_EQ(ARES_EBADSTR, ares_set_sortlist(channel_, "111.111.111.111/255.255.255.240*"));
EXPECT_EQ(ARES_SUCCESS, ares_set_sortlist(channel_, "xyzzy ; lwk"));
EXPECT_EQ(ARES_SUCCESS, ares_set_sortlist(channel_, "xyzzy ; 0x123"));
}
--
2.33.0

9
c-ares.spec
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@ -1,6 +1,6 @@
Name: c-ares
Version: 1.18.1
Release: 3
Release: 4
Summary: A C library for asynchronous DNS requests
License: MIT
@ -11,6 +11,7 @@ BuildRequires: gcc autoconf automake libtool g++
# Patch0 from Redhat is applied for stopping overriding AC_CONFIG_MACRO_DIR
Patch0: 0000-Use-RPM-compiler-options.patch
Patch1: backport-disable-live-tests.patch
Patch2: backport-add-str-len-check-in-config_sortlist-to-avoid-stack-overflow.patch
%description
This is c-ares, an asynchronous resolver library. It is intended for applications
@ -60,6 +61,12 @@ cd ../
%{_mandir}/man3/*
%changelog
* Fri Feb 10 2023 xignwei <xingwei14@h-partners.com> - 1.18.1-4
- Type:cves
- CVE:CVE-2022-4904
- SUG:NA
- DESC:fix CVE-2022-4904
* Tue Aug 02 2022 gaihuiying <eaglegai@163.com> - 1.18.1-3
- Type:bugfix
- Id:NA