From 399644e47874bff147afb19c89228901ac39340e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 15 Apr 2024 21:40:15 +0200 Subject: Adding upstream version 6.05.01. Signed-off-by: Daniel Baumann --- man2/seteuid.2 | 134 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 man2/seteuid.2 (limited to 'man2/seteuid.2') diff --git a/man2/seteuid.2 b/man2/seteuid.2 new file mode 100644 index 0000000..0c47f6a --- /dev/null +++ b/man2/seteuid.2 @@ -0,0 +1,134 @@ +.\" Copyright (C) 2001 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" [should really be seteuid.3] +.\" Modified, 27 May 2004, Michael Kerrisk +.\" Added notes on capability requirements +.\" +.TH seteuid 2 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +seteuid, setegid \- set effective user or group ID +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include +.PP +.BI "int seteuid(uid_t " euid ); +.BI "int setegid(gid_t " egid ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR seteuid (), +.BR setegid (): +.nf + _POSIX_C_SOURCE >= 200112L + || /* glibc <= 2.19: */ _BSD_SOURCE +.fi +.SH DESCRIPTION +.BR seteuid () +sets the effective user ID of the calling process. +Unprivileged processes may only set the effective user ID to the +real user ID, the effective user ID or the saved set-user-ID. +.PP +Precisely the same holds for +.BR setegid () +with "group" instead of "user". +.\" When +.\" .I euid +.\" equals \-1, nothing is changed. +.\" (This is an artifact of the implementation in glibc of seteuid() +.\" using setresuid(2).) +.SH RETURN VALUE +On success, zero is returned. +On error, \-1 is returned, and +.I errno +is set to indicate the error. +.PP +.IR Note : +there are cases where +.BR seteuid () +can fail even when the caller is UID 0; +it is a grave security error to omit checking for a failure return from +.BR seteuid (). +.SH ERRORS +.TP +.B EINVAL +The target user or group ID is not valid in this user namespace. +.TP +.B EPERM +In the case of +.BR seteuid (): +the calling process is not privileged (does not have the +.B CAP_SETUID +capability in its user namespace) and +.I euid +does not match the current real user ID, current effective user ID, +or current saved set-user-ID. +.IP +In the case of +.BR setegid (): +the calling process is not privileged (does not have the +.B CAP_SETGID +capability in its user namespace) and +.I egid +does not match the current real group ID, current effective group ID, +or current saved set-group-ID. +.SH VERSIONS +Setting the effective user (group) ID to the +saved set-user-ID (saved set-group-ID) is +possible since Linux 1.1.37 (1.1.38). +On an arbitrary system one should check +.BR _POSIX_SAVED_IDS . +.PP +Under glibc 2.0, +.BI seteuid( euid ) +is equivalent to +.BI setreuid(\-1, " euid" ) +and hence may change the saved set-user-ID. +Under glibc 2.1 and later, it is equivalent to +.BI setresuid(\-1, " euid" ", \-1)" +and hence does not change the saved set-user-ID. +Analogous remarks hold for +.BR setegid (), +with the difference that the change in implementation from +.BI setregid(\-1, " egid" ) +to +.BI setresgid(\-1, " egid" ", \-1)" +occurred in glibc 2.2 or 2.3 (depending on the hardware architecture). +.PP +According to POSIX.1, +.BR seteuid () +.RB ( setegid ()) +need not permit +.I euid +.RI ( egid ) +to be the same value as the current effective user (group) ID, +and some implementations do not permit this. +.SS C library/kernel differences +On Linux, +.BR seteuid () +and +.BR setegid () +are implemented as library functions that call, respectively, +.BR setreuid (2) +and +.BR setregid (2). +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001, 4.3BSD. +.SH SEE ALSO +.BR geteuid (2), +.BR setresuid (2), +.BR setreuid (2), +.BR setuid (2), +.BR capabilities (7), +.BR credentials (7), +.BR user_namespaces (7) -- cgit v1.2.3