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-rw-r--r--apt-pkg/contrib/arfile.cc14
-rwxr-xr-xtest/integration/test-cve-2020-2735013
-rw-r--r--test/interactive-helper/CMakeLists.txt2
-rw-r--r--test/interactive-helper/createdeb-cve-2020-27350.cc235
4 files changed, 263 insertions, 1 deletions
diff --git a/apt-pkg/contrib/arfile.cc b/apt-pkg/contrib/arfile.cc
index 5cb43c690..6d4a1f158 100644
--- a/apt-pkg/contrib/arfile.cc
+++ b/apt-pkg/contrib/arfile.cc
@@ -94,7 +94,12 @@ bool ARArchive::LoadHeaders()
delete Memb;
return _error->Error(_("Invalid archive member header"));
}
-
+
+ if (Left < 0 || Memb->Size > static_cast<unsigned long long>(Left))
+ {
+ delete Memb;
+ return _error->Error(_("Invalid archive member header"));
+ }
// Check for an extra long name string
if (memcmp(Head.Name,"#1/",3) == 0)
{
@@ -106,6 +111,13 @@ bool ARArchive::LoadHeaders()
delete Memb;
return _error->Error(_("Invalid archive member header"));
}
+
+ if (Len > Memb->Size)
+ {
+ delete Memb;
+ return _error->Error(_("Invalid archive member header"));
+ }
+
if (File.Read(S,Len) == false)
{
delete Memb;
diff --git a/test/integration/test-cve-2020-27350 b/test/integration/test-cve-2020-27350
new file mode 100755
index 000000000..6ee867bb3
--- /dev/null
+++ b/test/integration/test-cve-2020-27350
@@ -0,0 +1,13 @@
+#!/bin/sh
+set -e
+
+TESTDIR="$(readlink -f "$(dirname "$0")")"
+. "$TESTDIR/framework"
+setupenvironment
+configarchitecture "amd64"
+
+${APTTESTHELPERSBINDIR}/createdeb-cve-2020-27350 crash crash.deb
+testequal "E: Invalid archive member header" runapt ${APTTESTHELPERSBINDIR}/testdeb ./crash.deb
+
+${APTTESTHELPERSBINDIR}/createdeb-cve-2020-27350 loop loop.deb
+testequal "E: Invalid archive member header" runapt ${APTTESTHELPERSBINDIR}/testdeb ./loop.deb
diff --git a/test/interactive-helper/CMakeLists.txt b/test/interactive-helper/CMakeLists.txt
index f4238665d..565474afd 100644
--- a/test/interactive-helper/CMakeLists.txt
+++ b/test/interactive-helper/CMakeLists.txt
@@ -10,6 +10,8 @@ add_executable(aptdropprivs aptdropprivs.cc)
target_link_libraries(aptdropprivs apt-pkg)
add_executable(test_fileutl test_fileutl.cc)
target_link_libraries(test_fileutl apt-pkg)
+add_executable(createdeb-cve-2020-27350 createdeb-cve-2020-27350.cc)
+
add_library(noprofile SHARED libnoprofile.c)
target_link_libraries(noprofile ${CMAKE_DL_LIBS})
diff --git a/test/interactive-helper/createdeb-cve-2020-27350.cc b/test/interactive-helper/createdeb-cve-2020-27350.cc
new file mode 100644
index 000000000..9103c2137
--- /dev/null
+++ b/test/interactive-helper/createdeb-cve-2020-27350.cc
@@ -0,0 +1,235 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+struct Header
+{
+ char Name[16];
+ char MTime[12];
+ char UID[6];
+ char GID[6];
+ char Mode[8];
+ char Size[10];
+ char Magic[2];
+};
+
+struct TarHeader
+{
+ char Name[100];
+ char Mode[8];
+ char UserID[8];
+ char GroupID[8];
+ char Size[12];
+ char MTime[12];
+ char Checksum[8];
+ char LinkFlag;
+ char LinkName[100];
+ char MagicNumber[8];
+ char UserName[32];
+ char GroupName[32];
+ char Major[8];
+ char Minor[8];
+};
+
+// Call `write` and check the result.
+static void write_chk(int fd, const void *buf, size_t count)
+{
+ const ssize_t wr = write(fd, buf, count);
+ if (wr < 0)
+ {
+ const int err = errno;
+ fprintf(stderr, "Write failed: %s\n", strerror(err));
+ exit(EXIT_FAILURE);
+ }
+ if ((size_t)wr != count)
+ {
+ fprintf(stderr, "Incomplete write.\n");
+ exit(EXIT_FAILURE);
+ }
+}
+
+// Triggers a negative integer overflow at https://git.launchpad.net/ubuntu/+source/apt/tree/apt-pkg/contrib/arfile.cc?h=applied/ubuntu/focal-updates&id=4c264e60b524855b211751e1632ba48526f6b44d#n116:
+//
+// Memb->Size -= Len;
+//
+// Due to the integer overflow, the value of Memb->Size is 0xFFFFFFFFFFFFFFFF.
+// This leads to an out-of-memory error at https://git.launchpad.net/ubuntu/+source/python-apt/tree/python/arfile.cc?h=applied/ubuntu/focal-updates&id=0f7cc93acdb51d943114f1cd79002288c4ca4d24#n602:
+//
+// char* value = new char[member->Size];
+//
+// The out-of-memory error causes aptd to crash.
+static void createdeb_crash(const int fd)
+{
+ // Magic number
+ static const char *magic = "!<arch>\n";
+ write_chk(fd, magic, strlen(magic));
+
+ struct Header h;
+ memset(&h, 0, sizeof(h));
+
+ memcpy(h.Name, "control.tar ", sizeof(h.Name));
+ write_chk(fd, &h, sizeof(h));
+
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "data.tar ", sizeof(h.Name));
+ write_chk(fd, &h, sizeof(h));
+
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "#1/13 ", sizeof(h.Name));
+ strcpy(h.Size, "12");
+ write_chk(fd, &h, sizeof(h));
+ write_chk(fd, "debian-binary", 13);
+}
+
+// Triggers an infinite loop in `ARArchive::LoadHeaders()`.
+// The bug is due to the use of `strtoul` at https://git.launchpad.net/ubuntu/+source/apt/tree/apt-pkg/contrib/strutl.cc?h=applied/ubuntu/focal-updates&id=4c264e60b524855b211751e1632ba48526f6b44d#n1169:
+//
+// Res = strtoul(S,&End,Base);
+//
+// The problem is that `strtoul` accepts negative numbers. We exploit that here by setting the size string to "-60".
+static void createdeb_loop(const int fd)
+{
+ // Magic number
+ static const char *magic = "!<arch>\n";
+ write_chk(fd, magic, strlen(magic));
+
+ struct Header h;
+ memset(&h, 0, sizeof(h));
+
+ memcpy(h.Name, "#1/20 ", sizeof(h.Name));
+ strcpy(h.Size, "-60");
+ write_chk(fd, &h, sizeof(h));
+
+ char buf[20];
+ memset(buf, 0, sizeof(buf));
+ write_chk(fd, buf, sizeof(buf));
+}
+
+// Leaks a file descriptor in `debfile_new()`:
+//
+// https://git.launchpad.net/python-apt/tree/python/arfile.cc?h=2.0.0#n588
+//
+// If the .deb file is invalid then the function returns without deleting
+// `self`, which means that the file descriptor isn't closed.
+static void createdeb_leakfd(const int fd)
+{
+ // Magic number
+ static const char *magic = "!<arch>\n";
+ write_chk(fd, magic, strlen(magic));
+
+ struct Header h;
+ memset(&h, 0, sizeof(h));
+
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "data.tar ", sizeof(h.Name));
+ write_chk(fd, &h, sizeof(h));
+}
+
+static void set_checksum(unsigned char block[512])
+{
+ struct TarHeader *tar = (struct TarHeader *)&block[0];
+ memset(tar->Checksum, ' ', sizeof(tar->Checksum));
+ uint32_t sum = 0;
+ for (int i = 0; i < 512; i++)
+ {
+ sum += block[i];
+ }
+ snprintf(tar->Checksum, sizeof(tar->Checksum), "%o", sum);
+}
+
+// This does not trigger a vulnerability. It is just a basis for exploration.
+static void createdeb_test(const int fd)
+{
+ // Magic number
+ static const char *magic = "!<arch>\n";
+ write_chk(fd, magic, strlen(magic));
+
+ struct Header h;
+
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "data.tar ", sizeof(h.Name));
+ write_chk(fd, &h, sizeof(h));
+
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "debian-binary ", sizeof(h.Name));
+ strcpy(h.Size, "4");
+ write_chk(fd, &h, sizeof(h));
+ static const char *debian_binary = "2.0\n";
+ write_chk(fd, debian_binary, strlen(debian_binary));
+
+ static const char *control =
+ "Architecture: all\n"
+ "Package: kevsh\n\n";
+ memset(&h, 0, sizeof(h));
+ memcpy(h.Name, "control.tar ", sizeof(h.Name));
+ snprintf(h.Size, sizeof(h.Size), "%ld", (size_t)512 + 512);
+ write_chk(fd, &h, sizeof(h));
+
+ unsigned char block[512];
+ memset(block, 0, sizeof(block));
+ struct TarHeader *tar = (struct TarHeader *)&block[0];
+ strcpy(tar->Name, "control");
+ strcpy(tar->Mode, "644");
+ snprintf(tar->Size, sizeof(tar->Size), "%lo", strlen(control));
+ set_checksum(block);
+ write_chk(fd, block, sizeof(block));
+
+ memset(block, 0, sizeof(block));
+ strcpy((char *)block, control);
+ write_chk(fd, block, sizeof(block));
+}
+
+int main(int argc, char *argv[])
+{
+ if (argc != 3)
+ {
+ const char *progname = argc > 0 ? argv[0] : "a.out";
+ fprintf(
+ stderr,
+ "usage: %s <mode> <filename>\n"
+ "modes: loop, segv, leakfd\n",
+ progname);
+ return EXIT_FAILURE;
+ }
+
+ const char *mode = argv[1];
+ const char *filename = argv[2];
+
+ const int fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 00644);
+ if (fd < 0)
+ {
+ const int err = errno;
+ fprintf(stderr, "Could not open %s: %s\n", filename, strerror(err));
+ return EXIT_FAILURE;
+ }
+
+ if (strcmp(mode, "crash") == 0)
+ {
+ createdeb_crash(fd);
+ }
+ else if (strcmp(mode, "loop") == 0)
+ {
+ createdeb_loop(fd);
+ }
+ else if (strcmp(mode, "leakfd") == 0)
+ {
+ createdeb_leakfd(fd);
+ }
+ else if (strcmp(mode, "test") == 0)
+ {
+ createdeb_test(fd);
+ }
+ else
+ {
+ fprintf(stderr, "Mode not recognized: %s\n", mode);
+ }
+
+ close(fd);
+ return EXIT_SUCCESS;
+}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-01 19:33:16 +0000