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ladybird/Kernel/Syscalls/setuid.cpp

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Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:24:48 +03:00
* SPDX-License-Identifier: BSD-2-Clause
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
*/
#include <Kernel/Process.h>
namespace Kernel {
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$seteuid(uid_t new_euid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_euid != uid() && new_euid != suid() && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (euid() != new_euid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_euid = new_euid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setegid(gid_t new_egid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_egid != gid() && new_egid != sgid() && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (egid() != new_egid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_egid = new_egid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setuid(uid_t new_uid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_uid != uid() && new_uid != euid() && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (euid() != new_uid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_uid = new_uid;
m_euid = new_uid;
m_suid = new_uid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setgid(gid_t new_gid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_gid != gid() && new_gid != egid() && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (egid() != new_gid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_gid = new_gid;
m_egid = new_gid;
m_sgid = new_gid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setreuid(uid_t new_ruid, uid_t new_euid)
Kernel/LibC: Implement `setreuid`
2021-04-09 14:13:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel/LibC: Implement `setreuid`
2021-04-09 14:13:15 +03:00
REQUIRE_PROMISE(id);
if (new_ruid == (uid_t)-1)
new_ruid = uid();
if (new_euid == (uid_t)-1)
new_euid = euid();
auto ok = [this](uid_t id) { return id == uid() || id == euid() || id == suid(); };
if (!ok(new_ruid) || !ok(new_euid))
return EPERM;
if (new_ruid < (uid_t)-1 || new_euid < (uid_t)-1)
return EINVAL;
if (euid() != new_euid)
set_dumpable(false);
ProtectedDataMutationScope scope { *this };
m_uid = new_ruid;
m_euid = new_euid;
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setresuid(uid_t new_ruid, uid_t new_euid, uid_t new_suid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_ruid == (uid_t)-1)
new_ruid = uid();
if (new_euid == (uid_t)-1)
new_euid = euid();
if (new_suid == (uid_t)-1)
new_suid = suid();
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
auto ok = [this](uid_t id) { return id == uid() || id == euid() || id == suid(); };
if ((!ok(new_ruid) || !ok(new_euid) || !ok(new_suid)) && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (euid() != new_euid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_uid = new_ruid;
m_euid = new_euid;
m_suid = new_suid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setresgid(gid_t new_rgid, gid_t new_egid, gid_t new_sgid)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (new_rgid == (gid_t)-1)
new_rgid = gid();
if (new_egid == (gid_t)-1)
new_egid = egid();
if (new_sgid == (gid_t)-1)
new_sgid = sgid();
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
auto ok = [this](gid_t id) { return id == gid() || id == egid() || id == sgid(); };
if ((!ok(new_rgid) || !ok(new_egid) || !ok(new_sgid)) && !is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (egid() != new_egid)
Kernel+LibC: Introduce a "dumpable" flag for processes This new flag controls two things: - Whether the kernel will generate core dumps for the process - Whether the EUID:EGID should own the process's files in /proc Processes are automatically made non-dumpable when their EUID or EGID is changed, either via syscalls that specifically modify those ID's, or via sys$execve(), when a set-uid or set-gid program is executed. A process can change its own dumpable flag at any time by calling the new sys$prctl(PR_SET_DUMPABLE) syscall. Fixes #4504.
2020-12-25 20:27:42 +03:00
set_dumpable(false);
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_gid = new_rgid;
m_egid = new_egid;
m_sgid = new_sgid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Fix the return type for syscalls The Process::Handler type has KResultOr<FlatPtr> as its return type. Using a different return type with an equally-sized template parameter sort of works but breaks once that condition is no longer true, e.g. for KResultOr<int> on x86_64. Ideally the syscall handlers would also take FlatPtrs as their args so we can get rid of the reinterpret_cast for the function pointer but I didn't quite feel like cleaning that up as well.
2021-06-28 21:59:35 +03:00
KResultOr<FlatPtr> Process::sys$setgroups(size_t count, Userspace<const gid_t*> user_gids)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
{
Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
2021-07-18 21:20:12 +03:00
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
REQUIRE_PROMISE(id);
if (!is_superuser())
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EPERM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
if (!count) {
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
m_extra_gids.clear();
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
return 0;
}
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
Vector<gid_t> new_extra_gids;
Kernel: Harden sys$setgroups Vector usage against OOM
2021-04-30 13:10:55 +03:00
if (!new_extra_gids.try_resize(count))
return ENOMEM;
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
if (!copy_n_from_user(new_extra_gids.data(), user_gids, count))
Kernel: Make all syscall functions return KResultOr<T> This makes it a lot easier to return errors since we no longer have to worry about negating EFOO errors and can just return them flat.
2021-03-01 15:49:16 +03:00
return EFAULT;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
HashTable<gid_t> unique_extra_gids;
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
for (auto& extra_gid : new_extra_gids) {
if (extra_gid != gid())
unique_extra_gids.set(extra_gid);
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
}
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
ProtectedDataMutationScope scope { *this };
Kernel: Harden sys$setgroups Vector usage against OOM
2021-04-30 13:10:55 +03:00
if (!m_extra_gids.try_resize(unique_extra_gids.size()))
return ENOMEM;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
size_t i = 0;
Kernel: Move select Process members into protected memory Process member variable like m_euid are very valuable targets for kernel exploits and until now they have been writable at all times. This patch moves m_euid along with a whole bunch of other members into a new Process::ProtectedData struct. This struct is remapped as read-only memory whenever we don't need to write to it. This means that a kernel write primitive is no longer enough to overwrite a process's effective UID, you must first unprotect the protected data where the UID is stored. :^)
2021-03-10 21:59:46 +03:00
for (auto& extra_gid : unique_extra_gids) {
if (extra_gid == gid())
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
continue;
Kernel: Don't keep protected Process data in a separate allocation The previous architecture had a huge flaw: the pointer to the protected data was itself unprotected, allowing you to overwrite it at any time. This patch reorganizes the protected data so it's part of the Process class itself. (Actually, it's a new ProcessBase helper class.) We use the first 4 KB of Process objects themselves as the new storage location for protected data. Then we make Process objects page-aligned using MAKE_ALIGNED_ALLOCATED. This allows us to easily turn on/off write-protection for everything in the ProcessBase portion of Process. :^) Thanks to @bugaevc for pointing out the flaw! This is still not perfect but it's an improvement.
2021-03-11 15:13:05 +03:00
m_extra_gids[i++] = extra_gid;
Kernel: Move syscall implementations out of Process.cpp This is something I've been meaning to do for a long time, and here we finally go. This patch moves all sys$foo functions out of Process.cpp and into files in Kernel/Syscalls/. It's not exactly one syscall per file (although it could be, but I got a bit tired of the repetitive work here..) This makes hacking on individual syscalls a lot less painful since you don't have to rebuild nearly as much code every time. I'm also hopeful that this makes it easier to understand individual syscalls. :^)
2020-07-31 00:38:15 +03:00
}
return 0;
}
}
Reference in New Issue Copy Permalink