2:16 p.m.
Without this patch, at least tests/daemon-conf (which sticks
$builddir/src in the PATH) tries to execute the directory
$builddir/src/qemu rather than a real qemu binary.
* src/util/util.h (virFileExists): Adjust prototype.
(virFileIsExecutable): New prototype.
* src/util/util.c (virFindFileInPath): Reject non-executables and
directories. Avoid huge stack allocation.
(virFileExists): Use lighter-weight syscall.
(virFileIsExecutable): New function.
* src/libvirt_private.syms (util.h): Export new function.
---
New in v2: Require S_ISREG, not !S_ISDIR; avoid access(X_OK) and
instead document that ACLs are disregarded
src/libvirt_private.syms | 1 +
src/util/util.c | 53 ++++++++++++++++++++++++++++++---------------
src/util/util.h | 7 +++--
3 files changed, 40 insertions(+), 21 deletions(-)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index e9b8cb7..a166bd9 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -845,6 +845,7 @@ virFileDeletePid;
virFileExists;
virFileFindMountPoint;
virFileHasSuffix;
+virFileIsExecutable;
virFileLinkPointsTo;
virFileMakePath;
virFileMatchesNameSuffix;
diff --git a/src/util/util.c b/src/util/util.c
index 60feb79..18b38f4 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -1255,7 +1255,7 @@ int virFileResolveLink(const char *linkpath,
}
/*
- * Finds a requested file in the PATH env. e.g.:
+ * Finds a requested executable file in the PATH env. e.g.:
* "kvm-img" will return "/usr/bin/kvm-img"
*
* You must free the result
@@ -1263,19 +1263,18 @@ int virFileResolveLink(const char *linkpath,
char *virFindFileInPath(const char *file)
{
char *path;
- char pathenv[PATH_MAX];
- char *penv = pathenv;
+ char *pathiter;
char *pathseg;
- char fullpath[PATH_MAX];
+ char *fullpath = NULL;
if (file == NULL)
return NULL;
/* if we are passed an absolute path (starting with /), return a
- * copy of that path
+ * copy of that path, after validating that it is executable
*/
- if (file[0] == '/') {
- if (virFileExists(file))
+ if (IS_ABSOLUTE_FILE_NAME(file)) {
+ if (virFileIsExecutable(file))
return strdup(file);
else
return NULL;
@@ -1284,27 +1283,45 @@ char *virFindFileInPath(const char *file)
/* copy PATH env so we can tweak it */
path = getenv("PATH");
- if (path == NULL || virStrcpyStatic(pathenv, path) == NULL)
+ if (path == NULL || (path = strdup(path)) == NULL)
return NULL;
/* for each path segment, append the file to search for and test for
* it. return it if found.
*/
- while ((pathseg = strsep(&penv, ":")) != NULL) {
- snprintf(fullpath, PATH_MAX, "%s/%s", pathseg, file);
- if (virFileExists(fullpath))
- return strdup(fullpath);
+ pathiter = path;
+ while ((pathseg = strsep(&pathiter, ":")) != NULL) {
+ if (virAsprintf(&fullpath, "%s/%s", pathseg, file) < 0 ||
+ virFileIsExecutable(fullpath))
+ break;
+ VIR_FREE(fullpath);
}
- return NULL;
+ VIR_FREE(path);
+ return fullpath;
}
-int virFileExists(const char *path)
+
+bool virFileExists(const char *path)
{
- struct stat st;
+ return access(path, F_OK) == 0;
+}
- if (stat(path, &st) >= 0)
- return(1);
- return(0);
+/* Check that a file is regular and has executable bits.
+ *
+ * Note: In the presence of ACLs, this may return true for a file that
+ * would actually fail with EACCES for a given user, or false for a
+ * file that the user could actually execute, but setups with ACLs
+ * that weird are unusual. */
+bool
+virFileIsExecutable(const char *file)
+{
+ struct stat sb;
+
+ /* We would also want to check faccessat if we cared about ACLs,
+ * but we don't. */
+ return (stat(file, &sb) == 0 &&
+ S_ISREG(sb.st_mode) &&
+ (sb.st_mode & 0111) != 0);
}
#ifndef WIN32
diff --git a/src/util/util.h b/src/util/util.h
index 989962f..54c3058 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -1,8 +1,7 @@
-
/*
* utils.h: common, generic utility functions
*
- * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (C) 2010-2011 Red Hat, Inc.
* Copyright (C) 2006, 2007 Binary Karma
* Copyright (C) 2006 Shuveb Hussain
*
@@ -32,6 +31,7 @@
# include <sys/select.h>
# include <sys/types.h>
# include <stdarg.h>
+# include <stdbool.h>
# ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
@@ -120,7 +120,8 @@ int virFileResolveLink(const char *linkpath,
char *virFindFileInPath(const char *file);
-int virFileExists(const char *path);
+bool virFileExists(const char *file);
+bool virFileIsExecutable(const char *file);
char *virFileSanitizePath(const char *path);
--
1.7.3.4