85 lines
2.7 KiB
Diff
85 lines
2.7 KiB
Diff
From: Alex Rousskov <rousskov@measurement-factory.com>
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Date: Fri, 27 Oct 2023 21:27:20 +0000
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Subject: [PATCH] Exit without asserting when helper process startup fails
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(#1543)
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... to dup() after fork() and before execvp().
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Assertions are for handling program logic errors. Helper initialization
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code already handled system call errors correctly (i.e. by exiting the
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newly created helper process with an error), except for a couple of
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assert()s that could be triggered by dup(2) failures.
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This bug was discovered and detailed by Joshua Rogers at
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https://megamansec.github.io/Squid-Security-Audit/ipc-assert.html
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where it was filed as 'Assertion in Squid "Helper" Process Creator'.
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Conflict:NA
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Reference:https://github.com/squid-cache/squid/commit/6014c6648a2a54a4ecb7f952ea1163e0798f9264
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---
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src/ipc.cc | 32 ++++++++++++++++++++++++++------
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1 file changed, 26 insertions(+), 6 deletions(-)
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diff --git a/src/ipc.cc b/src/ipc.cc
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index 40d34b475..1afc4d5cf 100644
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--- a/src/ipc.cc
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+++ b/src/ipc.cc
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@@ -22,6 +22,11 @@
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#include "SquidConfig.h"
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#include "SquidIpc.h"
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#include "tools.h"
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+#include <cstdlib>
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+
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+#if HAVE_UNISTD_H
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+#include <unistd.h>
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+#endif
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static const char *hello_string = "hi there\n";
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#ifndef HELLO_BUF_SZ
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@@ -362,6 +367,22 @@ ipcCreate(int type, const char *prog, const char *const args[], const char *name
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}
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PutEnvironment();
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+
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+ // A dup(2) wrapper that reports and exits the process on errors. The
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+ // exiting logic is only suitable for this child process context.
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+ const auto dupOrExit = [prog,name](const int oldFd) {
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+ const auto newFd = dup(oldFd);
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+ if (newFd < 0) {
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+ const auto savedErrno = errno;
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+ debugs(54, DBG_CRITICAL, "ERROR: Helper process initialization failure: " << name <<
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+ Debug::Extra << "helper (CHILD) PID: " << getpid() <<
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+ Debug::Extra << "helper program name: " << prog <<
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+ Debug::Extra << "dup(2) system call error for FD " << oldFd << ": " << xstrerr(savedErrno));
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+ _exit(EXIT_FAILURE);
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+ }
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+ return newFd;
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+ };
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+
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/*
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* This double-dup stuff avoids problems when one of
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* crfd, cwfd, or debug_log are in the rage 0-2.
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@@ -369,17 +390,16 @@ ipcCreate(int type, const char *prog, const char *const args[], const char *name
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do {
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/* First make sure 0-2 is occupied by something. Gets cleaned up later */
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- x = dup(crfd);
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- assert(x > -1);
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- } while (x < 3 && x > -1);
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+ x = dupOrExit(crfd);
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+ } while (x < 3);
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close(x);
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- t1 = dup(crfd);
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+ t1 = dupOrExit(crfd);
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- t2 = dup(cwfd);
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+ t2 = dupOrExit(cwfd);
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- t3 = dup(fileno(debug_log));
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+ t3 = dupOrExit(fileno(debug_log));
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assert(t1 > 2 && t2 > 2 && t3 > 2);
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