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Actually prevent the loading of unknown kernel headers

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The previous fix that was part of the bcc-0.30.0 rebase didn't
actually do anything but print a warning. Actually fix the issue this
time.

Also add the python3-elftools dependency needed for bashreadline.

Resolves: RHEL-28769
Resolves: RHEL-36583
CVE CVE-2024-2314
This commit is contained in:
Jerome Marchand 2024-05-20 13:30:14 +02:00
parent deda5ca5c8
commit 410589b0f3
2 changed files with 84 additions and 1 deletions
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76
bcc-0.30.0-clang-fail-when-the-kheaders-ownership-is-wrong-4928.patch Normal file
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@ -0,0 +1,76 @@
From 5bc97bbc50b1ccf0c63f320ee73a2c0abe84b596 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@redhat.com>
Date: Fri, 17 May 2024 15:36:07 +0200
Subject: [PATCH] clang: fail when the kheaders ownership is wrong (#4928)
(#4985)
file_exists_and_ownedby() returns -1 when the file exists but its
ownership is unexpected, which is very misleading since anything non
zero is interpreted as true and a function with such a name is
expected to return a boolean. So currently all this does, is write a
warning message, and continues as if nothing is wrong.
Make file_exists_and_ownedby() returns false when the ownership is
wrong and have get_proc_kheaders() fails when this happen. Also have
all the *exists* functions return bool to avoid such issues in the
future.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
src/cc/frontends/clang/kbuild_helper.cc | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/src/cc/frontends/clang/kbuild_helper.cc b/src/cc/frontends/clang/kbuild_helper.cc
index 9409e4cc..5d3ad9c2 100644
--- a/src/cc/frontends/clang/kbuild_helper.cc
+++ b/src/cc/frontends/clang/kbuild_helper.cc
@@ -140,20 +140,26 @@ int KBuildHelper::get_flags(const char *uname_machine, vector<string> *cflags) {
return 0;
}
-static inline int file_exists_and_ownedby(const char *f, uid_t uid)
+static inline bool file_exists(const char *f)
+{
+ struct stat buffer;
+ return (stat(f, &buffer) == 0);
+}
+
+static inline bool file_exists_and_ownedby(const char *f, uid_t uid)
{
struct stat buffer;
int ret = stat(f, &buffer) == 0;
if (ret) {
if (buffer.st_uid != uid) {
std::cout << "ERROR: header file ownership unexpected: " << std::string(f) << "\n";
- return -1;
+ return false;
}
}
return ret;
}
-static inline int proc_kheaders_exists(void)
+static inline bool proc_kheaders_exists(void)
{
return file_exists_and_ownedby(PROC_KHEADERS_PATH, 0);
}
@@ -231,8 +237,14 @@ int get_proc_kheaders(std::string &dirpath)
uname_data.release);
dirpath = std::string(dirpath_tmp);
- if (file_exists_and_ownedby(dirpath_tmp, 0))
- return 0;
+ if (file_exists(dirpath_tmp)) {
+ if (file_exists_and_ownedby(dirpath_tmp, 0))
+ return 0;
+ else
+ // The path exists, but is owned by a non-root user
+ // Something fishy is going on
+ return -EEXIST;
+ }
// First time so extract it
return extract_kheaders(dirpath, uname_data);
--
2.44.0

9
bcc.spec
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@ -25,11 +25,13 @@
Name: bcc
Version: 0.30.0
Release: 2%{?dist}
Release: 3%{?dist}
Summary: BPF Compiler Collection (BCC)
License: ASL 2.0
URL: https://github.com/iovisor/bcc
Source0: %{url}/archive/v%{version}/%{name}-%{version}.tar.gz
Patch0: %%{name}-%%{version}-clang-fail-when-the-kheaders-ownership-is-wrong-4928.patch
# Arches will be included as upstream support is added and dependencies are
# satisfied in the respective arches
@ -113,6 +115,7 @@ Summary: Command line tools for BPF Compiler Collection (BCC)
Requires: bcc = %{version}-%{release}
Requires: python3-%{name} = %{version}-%{release}
Requires: python3-netaddr
Requires: python3-pyelftools
%description tools
Command line tools for BPF Compiler Collection (BCC)
@ -256,6 +259,10 @@ cp -a libbpf-tools/tmp-install/bin/* %{buildroot}/%{_sbindir}/
%endif
%changelog
* Mon May 20 2024 Jerome Marchand <jmarchan@redhat.com> - 0.30.0-3
- Really prevent the loading of compromised headers (RHEL-28769, CVE-2024-2314)
- Add python3-pyelftools dependency (RHEL-36583)
* Fri May 03 2024 Jerome Marchand <jmarchan@redhat.com> - 0.30.0-2
- Rebuild (distrobaker didn't take last build)