69 lines
2.4 KiB
Diff
69 lines
2.4 KiB
Diff
From d6a5130c5f18499da26eef88f52da75c9e33d63d Mon Sep 17 00:00:00 2001
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From: Brendan Gregg <brendan@intel.com>
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Date: Thu, 7 Mar 2024 05:27:14 +1100
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Subject: [PATCH] clang: check header ownership (#4928)
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Example testing with a brendan-owned /tmp/kheaders file (note the "ERROR:" message):
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~/bcc/build$ sudo /usr/share/bcc/tools/biosnoop
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ERROR: header file ownership unexpected: /tmp/kheaders-5.15.47-internal
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<built-in>:1:10: fatal error: './include/linux/kconfig.h' file not found
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#include "./include/linux/kconfig.h"
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^~~~~~~~~~~~~~~~~~~~~~~~~~~
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1 error generated.
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Traceback (most recent call last):
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File "/usr/share/bcc/tools/biosnoop", line 335, in <module>
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b = BPF(text=bpf_text)
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File "/usr/lib/python3/dist-packages/bcc-0.1.5+6cd27218-py3.10.egg/bcc/__init__.py", line 479, in __init__
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Exception: Failed to compile BPF module <text>
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~/bcc/build$ ls -lhd /tmp/kheaders-5.15.47-internal
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drwxrwxr-x 2 brendan dev 4.0K Mar 6 02:50 /tmp/kheaders-5.15.47-internal
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No error when chown'd back to root.
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---
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src/cc/frontends/clang/kbuild_helper.cc | 15 +++++++++++----
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1 file changed, 11 insertions(+), 4 deletions(-)
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diff --git a/src/cc/frontends/clang/kbuild_helper.cc b/src/cc/frontends/clang/kbuild_helper.cc
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index 933aec8e..1b291469 100644
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--- a/src/cc/frontends/clang/kbuild_helper.cc
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+++ b/src/cc/frontends/clang/kbuild_helper.cc
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@@ -140,15 +140,22 @@ int KBuildHelper::get_flags(const char *uname_machine, vector<string> *cflags) {
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return 0;
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}
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-static inline int file_exists(const char *f)
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+static inline int file_exists_and_ownedby(const char *f, uid_t uid)
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{
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struct stat buffer;
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- return (stat(f, &buffer) == 0);
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+ int ret;
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+ if ((ret = stat(f, &buffer)) == 0) {
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+ if (buffer.st_uid != uid) {
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+ std::cout << "ERROR: header file ownership unexpected: " << std::string(f) << "\n";
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+ return -1;
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+ }
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+ }
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+ return ret;
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}
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static inline int proc_kheaders_exists(void)
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{
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- return file_exists(PROC_KHEADERS_PATH);
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+ return file_exists_and_ownedby(PROC_KHEADERS_PATH, 0);
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}
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static inline int extract_kheaders(const std::string &dirpath,
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@@ -214,7 +221,7 @@ int get_proc_kheaders(std::string &dirpath)
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snprintf(dirpath_tmp, 256, "/tmp/kheaders-%s", uname_data.release);
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dirpath = std::string(dirpath_tmp);
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- if (file_exists(dirpath_tmp))
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+ if (file_exists_and_ownedby(dirpath_tmp, 0))
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return 0;
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// First time so extract it
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--
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2.43.2
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