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Use multilib rules to look for a 64-bit group plugin on failure.

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If sudo_dso_load() fails on a 64-bit system, try to load a 64-bit
native version of the file using system-dependent multilib rules.
If we don't support multilib on the platform, check for a version
of the file that ends in "64" before the .so suffix.
This commit is contained in:
Todd C. Miller
2022-08-11 19:34:50 -06:00
parent 68b26056f9
commit 158facf6d5
3 changed files with 174 additions and 23 deletions
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32
docs/sudoers.man.in
View File

@@ -25,7 +25,7 @@
.nr BA @BAMAN@
.nr LC @LCMAN@
.nr PS @PSMAN@
.TH "SUDOERS" "@mansectform@" "July 29, 2022" "Sudo @PACKAGE_VERSION@" "File Formats Manual"
.TH "SUDOERS" "@mansectform@" "August 11, 2022" "Sudo @PACKAGE_VERSION@" "File Formats Manual"
.nh
.if n .ad l
.SH "NAME"
@@ -3410,7 +3410,7 @@ has completed but before the new command has had a chance to run.
In the case of a path name or argument mismatch, the command will be sent a
\fRSIGKILL\fR
signal and terminated.
This can help prevent a time of check vs. time of use issue with
This can help prevent a time of check versus time of use issue with
intercept mode where the
execve(2)
arguments could be altered after the
@@ -4979,6 +4979,34 @@ These arguments (if any) will be passed to the plugin's initialization function.
If arguments are present, the string must be enclosed in double quotes
(\&"").
.sp
On 64-bit systems, if the plugin is present but cannot be loaded,
\fBsudoers\fR
will look for a 64-bit version and, if it exists, load that as a fallback.
The exact rules for this vary by system.
On Solaris, if the plugin is stored in a directory ending in
\(lqlib\(rq,
\fBsudoers\fR
will create a fallback path by appending
\(lq/64\(rq
to the directory name;
\fI/usr/lib/sudo_plugin.so\fR
becomes
\fI/usr/lib/64/sudo_plugin.so\fR.
On Linux, a directory ending in
\(lqlib\(rq
will be transformed to
\(lqlib64\(rq
as the fallback path;
\fI/usr/lib/sudo_plugin.so\fR
becomes
\fI/usr/lib64/sudo_plugin.so\fR.
On all other systems, the fallback path is generated by adding a
\(lq64\(rq
before the file extension;
\fIsudo_plugin.so\fR
becomes
\fIsudo_plugin64.so\fR.
.sp
For more information see
\fIGROUP PROVIDER PLUGINS\fR.
.TP 14n

32
docs/sudoers.mdoc.in
View File

@@ -25,7 +25,7 @@
.nr BA @BAMAN@
.nr LC @LCMAN@
.nr PS @PSMAN@
.Dd July 29, 2022
.Dd August 11, 2022
.Dt SUDOERS @mansectform@
.Os Sudo @PACKAGE_VERSION@
.Sh NAME
@@ -3231,7 +3231,7 @@ has completed but before the new command has had a chance to run.
In the case of a path name or argument mismatch, the command will be sent a
.Dv SIGKILL
signal and terminated.
This can help prevent a time of check vs. time of use issue with
This can help prevent a time of check versus time of use issue with
intercept mode where the
.Xr execve 2
arguments could be altered after the
@@ -4690,6 +4690,34 @@ These arguments (if any) will be passed to the plugin's initialization function.
If arguments are present, the string must be enclosed in double quotes
.Pq \&"" .
.Pp
On 64-bit systems, if the plugin is present but cannot be loaded,
.Nm
will look for a 64-bit version and, if it exists, load that as a fallback.
The exact rules for this vary by system.
On Solaris, if the plugin is stored in a directory ending in
.Dq lib ,
.Nm
will create a fallback path by appending
.Dq /64
to the directory name;
.Pa /usr/lib/sudo_plugin.so
becomes
.Pa /usr/lib/64/sudo_plugin.so .
On Linux, a directory ending in
.Dq lib
will be transformed to
.Dq lib64
as the fallback path;
.Pa /usr/lib/sudo_plugin.so
becomes
.Pa /usr/lib64/sudo_plugin.so .
On all other systems, the fallback path is generated by adding a
.Dq 64
before the file extension;
.Pa sudo_plugin.so
becomes
.Pa sudo_plugin64.so .
.Pp
For more information see
.Sx "GROUP PROVIDER PLUGINS" .
.It lecture

103
plugins/sudoers/group_plugin.c
View File

@@ -40,6 +40,90 @@ static void *group_handle;
static struct sudoers_group_plugin *group_plugin;
const char *path_plugin_dir = _PATH_SUDO_PLUGIN_DIR;
/*
* Check for a fallback path when the original group plugin is not loadable.
* Returns true on success, rewriting path and filling in sb, else false.
*/
static bool
group_plugin_fallback(char *path, size_t pathsize, struct stat *sb)
{
#if defined(__LP64__)
char newpath[PATH_MAX];
bool ret = false;
int len;
debug_decl(group_plugin_fallback, SUDOERS_DEBUG_UTIL);
# if defined(__sun__) || defined(__linux__)
/*
* Solaris uses /lib/64 and /usr/lib/64 for 64-bit libraries.
* Linux may use /lib64 and /usr/lib64 for 64-bit libraries.
* If dirname(path) ends in /lib, try /lib/64 (Solaris) or /lib64 (Linux).
*/
# if defined(__sun__)
const char *lib64 = "lib/64";
# else
const char *lib64 = "lib64";
# endif
const char *base, *slash;
int dirlen;
slash = strrchr(path, '/');
if (slash == NULL) {
goto done;
}
base = slash + 1;
/* Collapse consecutive slashes. */
while (slash > path && slash[-1] == '/') {
slash--;
}
/* If directory ends in /lib/, try again with /lib/64/ or /lib64/. */
dirlen = slash - path;
if (dirlen < 4 || strncmp(slash - 4, "/lib", 4) != 0) {
goto done;
}
dirlen -= 4;
len = snprintf(newpath, sizeof(newpath), "%.*s/%s/%s", dirlen, path, lib64,
base);
# else /* !__sun__ && !__linux__ */
/*
* Multilib not supported, check for a path of the form libfoo64.so.
*/
const char *dot;
int plen;
dot = strrchr(path, '.');
if (dot == NULL) {
goto done;
}
plen = dot - path;
/* If basename(path) doesn't match libfoo64.so, try adding the 64. */
if (plen >= 2 && strncmp(dot - 2, "64", 2) == 0) {
goto done;
}
len = snprintf(newpath, sizeof(newpath), "%.*s64%s", plen, path, dot);
# endif /* __sun__ || __linux__ */
if (len < 0 || len >= ssizeof(newpath)) {
errno = ENAMETOOLONG;
goto done;
}
if (stat(newpath, sb) == -1) {
goto done;
}
if (strlcpy(path, newpath, pathsize) >= pathsize) {
errno = ENAMETOOLONG;
goto done;
}
ret = true;
done:
debug_return_bool(ret);
#else
return false;
#endif /* __LP64__ */
}
/*
* Load the specified plugin and run its init function.
* Returns -1 if unable to open the plugin, else it returns
@@ -52,6 +136,7 @@ group_plugin_load(const char *plugin_info)
char *args, path[PATH_MAX];
char **argv = NULL;
int len, rc = -1;
bool retry = true;
debug_decl(group_plugin_load, SUDOERS_DEBUG_UTIL);
/*
@@ -72,13 +157,14 @@ group_plugin_load(const char *plugin_info)
(*plugin_info != '/') ? path_plugin_dir : "", plugin_info);
goto done;
}
/* Check owner and mode of plugin path. */
if (stat(path, &sb) != 0) {
sudo_warn("%s", path);
goto done;
}
for (;;) {
if (!sudo_conf_developer_mode()) {
/* Check owner and mode of plugin path. */
if (sb.st_uid != ROOT_UID) {
sudo_warnx(U_("%s must be owned by uid %d"), path, ROOT_UID);
goto done;
@@ -89,14 +175,23 @@ group_plugin_load(const char *plugin_info)
}
}
/* Open plugin and map in symbol. */
group_handle = sudo_dso_load(path, SUDO_DSO_LAZY|SUDO_DSO_GLOBAL);
if (!group_handle) {
if (group_handle != NULL) {
break;
}
if (!retry || !group_plugin_fallback(path, sizeof(path), &sb)) {
const char *errstr = sudo_dso_strerror();
sudo_warnx(U_("unable to load %s: %s"), path,
errstr ? errstr : "unknown error");
goto done;
}
/* Retry once with the fallback path. */
retry = false;
}
/* Map in symbol from group plugin. */
group_plugin = sudo_dso_findsym(group_handle, "group_plugin");
if (group_plugin == NULL) {
sudo_warnx(U_("unable to find symbol \"group_plugin\" in %s"), path);