259e5e6c75
With this change, calling prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) disables privilege granting operations at execve-time. For example, a process will not be able to execute a setuid binary to change their uid or gid if this bit is set. The same is true for file capabilities. Additionally, LSM_UNSAFE_NO_NEW_PRIVS is defined to ensure that LSMs respect the requested behavior. To determine if the NO_NEW_PRIVS bit is set, a task may call prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0); It returns 1 if set and 0 if it is not set. If any of the arguments are non-zero, it will return -1 and set errno to -EINVAL. (PR_SET_NO_NEW_PRIVS behaves similarly.) This functionality is desired for the proposed seccomp filter patch series. By using PR_SET_NO_NEW_PRIVS, it allows a task to modify the system call behavior for itself and its child tasks without being able to impact the behavior of a more privileged task. Another potential use is making certain privileged operations unprivileged. For example, chroot may be considered "safe" if it cannot affect privileged tasks. Note, this patch causes execve to fail when PR_SET_NO_NEW_PRIVS is set and AppArmor is in use. It is fixed in a subsequent patch. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Eric Paris <eparis@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> v18: updated change desc v17: using new define values as per 3.4 Signed-off-by: James Morris <james.l.morris@oracle.com>
142 lines
4.8 KiB
C
142 lines
4.8 KiB
C
#ifndef _LINUX_PRCTL_H
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#define _LINUX_PRCTL_H
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/* Values to pass as first argument to prctl() */
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#define PR_SET_PDEATHSIG 1 /* Second arg is a signal */
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#define PR_GET_PDEATHSIG 2 /* Second arg is a ptr to return the signal */
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/* Get/set current->mm->dumpable */
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#define PR_GET_DUMPABLE 3
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#define PR_SET_DUMPABLE 4
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/* Get/set unaligned access control bits (if meaningful) */
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#define PR_GET_UNALIGN 5
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#define PR_SET_UNALIGN 6
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# define PR_UNALIGN_NOPRINT 1 /* silently fix up unaligned user accesses */
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# define PR_UNALIGN_SIGBUS 2 /* generate SIGBUS on unaligned user access */
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/* Get/set whether or not to drop capabilities on setuid() away from
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* uid 0 (as per security/commoncap.c) */
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#define PR_GET_KEEPCAPS 7
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#define PR_SET_KEEPCAPS 8
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/* Get/set floating-point emulation control bits (if meaningful) */
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#define PR_GET_FPEMU 9
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#define PR_SET_FPEMU 10
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# define PR_FPEMU_NOPRINT 1 /* silently emulate fp operations accesses */
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# define PR_FPEMU_SIGFPE 2 /* don't emulate fp operations, send SIGFPE instead */
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/* Get/set floating-point exception mode (if meaningful) */
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#define PR_GET_FPEXC 11
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#define PR_SET_FPEXC 12
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# define PR_FP_EXC_SW_ENABLE 0x80 /* Use FPEXC for FP exception enables */
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# define PR_FP_EXC_DIV 0x010000 /* floating point divide by zero */
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# define PR_FP_EXC_OVF 0x020000 /* floating point overflow */
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# define PR_FP_EXC_UND 0x040000 /* floating point underflow */
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# define PR_FP_EXC_RES 0x080000 /* floating point inexact result */
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# define PR_FP_EXC_INV 0x100000 /* floating point invalid operation */
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# define PR_FP_EXC_DISABLED 0 /* FP exceptions disabled */
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# define PR_FP_EXC_NONRECOV 1 /* async non-recoverable exc. mode */
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# define PR_FP_EXC_ASYNC 2 /* async recoverable exception mode */
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# define PR_FP_EXC_PRECISE 3 /* precise exception mode */
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/* Get/set whether we use statistical process timing or accurate timestamp
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* based process timing */
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#define PR_GET_TIMING 13
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#define PR_SET_TIMING 14
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# define PR_TIMING_STATISTICAL 0 /* Normal, traditional,
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statistical process timing */
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# define PR_TIMING_TIMESTAMP 1 /* Accurate timestamp based
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process timing */
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#define PR_SET_NAME 15 /* Set process name */
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#define PR_GET_NAME 16 /* Get process name */
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/* Get/set process endian */
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#define PR_GET_ENDIAN 19
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#define PR_SET_ENDIAN 20
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# define PR_ENDIAN_BIG 0
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# define PR_ENDIAN_LITTLE 1 /* True little endian mode */
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# define PR_ENDIAN_PPC_LITTLE 2 /* "PowerPC" pseudo little endian */
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/* Get/set process seccomp mode */
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#define PR_GET_SECCOMP 21
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#define PR_SET_SECCOMP 22
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/* Get/set the capability bounding set (as per security/commoncap.c) */
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#define PR_CAPBSET_READ 23
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#define PR_CAPBSET_DROP 24
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/* Get/set the process' ability to use the timestamp counter instruction */
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#define PR_GET_TSC 25
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#define PR_SET_TSC 26
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# define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
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# define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
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/* Get/set securebits (as per security/commoncap.c) */
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#define PR_GET_SECUREBITS 27
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#define PR_SET_SECUREBITS 28
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/*
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* Get/set the timerslack as used by poll/select/nanosleep
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* A value of 0 means "use default"
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*/
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#define PR_SET_TIMERSLACK 29
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#define PR_GET_TIMERSLACK 30
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#define PR_TASK_PERF_EVENTS_DISABLE 31
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#define PR_TASK_PERF_EVENTS_ENABLE 32
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/*
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* Set early/late kill mode for hwpoison memory corruption.
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* This influences when the process gets killed on a memory corruption.
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*/
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#define PR_MCE_KILL 33
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# define PR_MCE_KILL_CLEAR 0
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# define PR_MCE_KILL_SET 1
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# define PR_MCE_KILL_LATE 0
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# define PR_MCE_KILL_EARLY 1
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# define PR_MCE_KILL_DEFAULT 2
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#define PR_MCE_KILL_GET 34
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/*
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* Tune up process memory map specifics.
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*/
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#define PR_SET_MM 35
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# define PR_SET_MM_START_CODE 1
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# define PR_SET_MM_END_CODE 2
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# define PR_SET_MM_START_DATA 3
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# define PR_SET_MM_END_DATA 4
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# define PR_SET_MM_START_STACK 5
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# define PR_SET_MM_START_BRK 6
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# define PR_SET_MM_BRK 7
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/*
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* Set specific pid that is allowed to ptrace the current task.
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* A value of 0 mean "no process".
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*/
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#define PR_SET_PTRACER 0x59616d61
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# define PR_SET_PTRACER_ANY ((unsigned long)-1)
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#define PR_SET_CHILD_SUBREAPER 36
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#define PR_GET_CHILD_SUBREAPER 37
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/*
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* If no_new_privs is set, then operations that grant new privileges (i.e.
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* execve) will either fail or not grant them. This affects suid/sgid,
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* file capabilities, and LSMs.
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*
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* Operations that merely manipulate or drop existing privileges (setresuid,
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* capset, etc.) will still work. Drop those privileges if you want them gone.
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*
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* Changing LSM security domain is considered a new privilege. So, for example,
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* asking selinux for a specific new context (e.g. with runcon) will result
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* in execve returning -EPERM.
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*/
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#define PR_SET_NO_NEW_PRIVS 38
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#define PR_GET_NO_NEW_PRIVS 39
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#endif /* _LINUX_PRCTL_H */
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