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3 changed files with 166 additions and 1 deletions

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@ -0,0 +1,57 @@
From a83dae404feac517695c23ff43ce1e116e2bfbe0 Mon Sep 17 00:00:00 2001
From: Michael Catanzaro <mcatanzaro@gnome.org>
Date: Wed, 9 Sep 2020 11:12:02 -0500
Subject: [PATCH] Rewrite url::recvline to be nonrecursive
This function processes network input. It's semi-trusted, because the
PAC ought to be trusted. But we still shouldn't allow it to control how
far we recurse. A malicious PAC can cause us to overflow the stack by
sending a sufficiently-long line without any '\n' character.
Also, this function failed to properly handle EINTR, so let's fix that
too, for good measure.
Fixes #134
---
libproxy/url.cpp | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
diff --git a/libproxy/url.cpp b/libproxy/url.cpp
index ee776b2..68d69cd 100644
--- a/libproxy/url.cpp
+++ b/libproxy/url.cpp
@@ -388,16 +388,24 @@ string url::to_string() const {
return m_orig;
}
-static inline string recvline(int fd) {
- // Read a character.
- // If we don't get a character, return empty string.
- // If we are at the end of the line, return empty string.
- char c = '\0';
-
- if (recv(fd, &c, 1, 0) != 1 || c == '\n')
- return "";
-
- return string(1, c) + recvline(fd);
+static string recvline(int fd) {
+ string line;
+ int ret;
+
+ // Reserve arbitrary amount of space to avoid small memory reallocations.
+ line.reserve(128);
+
+ do {
+ char c;
+ ret = recv(fd, &c, 1, 0);
+ if (ret == 1) {
+ if (c == '\n')
+ return line;
+ line += c;
+ }
+ } while (ret == 1 || (ret == -1 && errno == EINTR));
+
+ return line;
}
char* url::get_pac() {

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@ -0,0 +1,93 @@
From 4411b523545b22022b4be7d0cac25aa170ae1d3e Mon Sep 17 00:00:00 2001
From: Fei Li <lifeibiren@gmail.com>
Date: Fri, 17 Jul 2020 02:18:37 +0800
Subject: [PATCH] Fix buffer overflow when PAC is enabled
The bug was found on Windows 10 (MINGW64) when PAC is enabled. It turned
out to be the large PAC file (more than 102400 bytes) returned by a
local proxy program with no content-length present.
---
libproxy/url.cpp | 44 +++++++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 13 deletions(-)
diff --git a/libproxy/url.cpp b/libproxy/url.cpp
index ee776b2..8684086 100644
--- a/libproxy/url.cpp
+++ b/libproxy/url.cpp
@@ -54,7 +54,7 @@ using namespace std;
#define PAC_MIME_TYPE_FB "text/plain"
// This is the maximum pac size (to avoid memory attacks)
-#define PAC_MAX_SIZE 102400
+#define PAC_MAX_SIZE 0x800000
// This is the default block size to use when receiving via HTTP
#define PAC_HTTP_BLOCK_SIZE 512
@@ -478,15 +478,13 @@ char* url::get_pac() {
}
// Get content
- unsigned int recvd = 0;
- buffer = new char[PAC_MAX_SIZE];
- memset(buffer, 0, PAC_MAX_SIZE);
+ std::vector<char> dynamic_buffer;
do {
unsigned int chunk_length;
if (chunked) {
// Discard the empty line if we received a previous chunk
- if (recvd > 0) recvline(sock);
+ if (!dynamic_buffer.empty()) recvline(sock);
// Get the chunk-length line as an integer
if (sscanf(recvline(sock).c_str(), "%x", &chunk_length) != 1 || chunk_length == 0) break;
@@ -498,21 +496,41 @@ char* url::get_pac() {
if (content_length >= PAC_MAX_SIZE) break;
- while (content_length == 0 || recvd != content_length) {
- int r = recv(sock, buffer + recvd,
- content_length == 0 ? PAC_HTTP_BLOCK_SIZE
- : content_length - recvd, 0);
+ while (content_length == 0 || dynamic_buffer.size() != content_length) {
+ // Calculate length to recv
+ unsigned int length_to_read = PAC_HTTP_BLOCK_SIZE;
+ if (content_length > 0)
+ length_to_read = content_length - dynamic_buffer.size();
+
+ // Prepare buffer
+ dynamic_buffer.resize(dynamic_buffer.size() + length_to_read);
+
+ int r = recv(sock, dynamic_buffer.data() + dynamic_buffer.size() - length_to_read, length_to_read, 0);
+
+ // Shrink buffer to fit
+ if (r >= 0)
+ dynamic_buffer.resize(dynamic_buffer.size() - length_to_read + r);
+
+ // PAC size too large, discard
+ if (dynamic_buffer.size() >= PAC_MAX_SIZE) {
+ chunked = false;
+ dynamic_buffer.clear();
+ break;
+ }
+
if (r <= 0) {
chunked = false;
break;
}
- recvd += r;
}
} while (chunked);
- if (content_length != 0 && string(buffer).size() != content_length) {
- delete[] buffer;
- buffer = NULL;
+ if (content_length == 0 || content_length == dynamic_buffer.size()) {
+ buffer = new char[dynamic_buffer.size() + 1];
+ if (!dynamic_buffer.empty()) {
+ memcpy(buffer, dynamic_buffer.data(), dynamic_buffer.size());
+ }
+ buffer[dynamic_buffer.size()] = '\0';
}
}

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@ -4,7 +4,7 @@
Name: libproxy Name: libproxy
Version: 0.4.15 Version: 0.4.15
Release: 5.2%{?dist} Release: 5.5%{?dist}
Summary: A library handling all the details of proxy configuration Summary: A library handling all the details of proxy configuration
Group: System Environment/Libraries Group: System Environment/Libraries
@ -15,6 +15,12 @@ Source0: https://github.com/libproxy/%{name}/archive/%{version}.tar.gz
Source1: proxy.1 Source1: proxy.1
Patch1: libproxy-0.4.11-crash.patch Patch1: libproxy-0.4.11-crash.patch
# https://bugzilla.redhat.com/show_bug.cgi?id=1880350
Patch2: libproxy-0.4.15-fix-CVE-2020-25219.patch
# https://bugzilla.redhat.com/show_bug.cgi?id=1883584
Patch3: libproxy-0.4.15-fix-pac-buffer-overflow.patch
BuildRequires: libmodman-devel >= 2.0.1 BuildRequires: libmodman-devel >= 2.0.1
BuildRequires: cmake >= 2.6.0 BuildRequires: cmake >= 2.6.0
@ -181,6 +187,15 @@ make test
%changelog %changelog
* Thu Aug 15 2024 Michael Santana <msantana@redhat.com> - 0.4.15-5.5
- Bump up version number
* Tue Jul 30 2024 Michael Santana <msantana@redhat.com> - 0.4.15-5.4
- Fix PAC buffer overflow (#1869639)
* Tue Jul 30 2024 Michael Santana <msantana@redhat.com> - 0.4.15-5.3
- Fix CVE-2020-25219 (#1880349)
* Thu May 31 2018 Dan Winship <danw@redhat.com> - 0.4.15-5.2 * Thu May 31 2018 Dan Winship <danw@redhat.com> - 0.4.15-5.2
- Drop pacrunner-mozjs (#1571640) - Drop pacrunner-mozjs (#1571640)