diff options
| -rw-r--r-- | lib/libc/sys/issetugid.2 | 69 |
1 files changed, 38 insertions, 31 deletions
diff --git a/lib/libc/sys/issetugid.2 b/lib/libc/sys/issetugid.2 index aca73d1..6babf48 100644 --- a/lib/libc/sys/issetugid.2 +++ b/lib/libc/sys/issetugid.2 @@ -31,12 +31,14 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" +.\" $Id$ +.\" .Dd August, 25 1996 .Dt ISSETUGID 2 -.Os OpenBSD 2.0 +.Os .Sh NAME .Nm issetugid -.Nd is current executable running setuid or setgid +.Nd is current process tainted by uid or gid changes .Sh SYNOPSIS .Fd #include <unistd.h> .Ft int @@ -44,31 +46,31 @@ .Sh DESCRIPTION The .Fn issetugid -function returns 1 if the process was made setuid or setgid as -the result of the last -.Fn execve -system call. -Otherwise it returns 0. +function returns 1 if the process environment or memory address space +is considered ``tainted'', and returns 0 otherwise. .Pp -This system call exists so that library routines (inside libc, libtermlib, -or other libraries) can gaurantee safe behavior when used inside -setuid or setgid programs. -Some library routines may not be passed sufficient information to know -if the current program was started setuid or setgid because higher level -calling code may have made changes to the uid or the euid. -In particular, it is wise to use this call to determine if a -pathname returned from a -.Fn getenv -call may safely be used to -.Fn open -the specified file. +A process is tainted if it was created as a result of an +.Xr execve 2 +system call which had either of the setuid or setgid bits set (and extra +privileges were given as a result) or if it has changed any of it's real, +effective or saved user or group ID's since it began execution. .Pp -.Fn issetugid -is unaffected by calls to -.Fn setuid , -.Fn fork , -and other such calls. It is only controlled by -.Fn execve . +This system call exists so that library routines (eg: libc, libtermcap) +can reliably determine if it is safe to use information +that was obtained from the user, in particular the results from +.Xr getenv 3 +should be viewed with suspicion if it is used to control operation. +.Pp +A ``tainted'' status is inherited by child processes as a result of the +.Xr fork 2 +system call (or other library code that calls fork, such as +.Xr popen 3 ). +.Pp +It is assumed that a program that clears all privileges as it prepares +to execute another will also reset the environment, hence the ``tainted'' +status will not be passed on. This is important for programs such as +.Xr su 1 +which begin setuid but need to be able to create an untainted process. .Sh ERRORS The .Fn issetugid @@ -76,12 +78,17 @@ function is always successful, and no return value is reserved to indicate an error. .Sh SEE ALSO .Xr execve 2 , -.Xr setuid 2 , -.Xr seteuid 2, +.Xr fork 2 , .Xr setgid 2 , -.Xr setegid 2 +.Xr setegid 2 , +.Xr seteuid 2 , +.Xr setregid 2 , +.Xr setregid 2 , +.Xr setuid 2 .Sh HISTORY A -.Fn lstat -function call appeared in -OpenBSD 2.0 +.Fn issetugid +function call first appeared in +.Ox 2.0 +and was also implemented in +.Fx 3.0 . |
