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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-16 11:30:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-16 11:30:07 -0700
commit3c69914b4c7b0b72ff0275c14743778057ee8a6e (patch)
tree9361c7c4f55c1647d36745bd74a263869552f881
parent2954152298c37804dab49d630aa959625b50cf64 (diff)
parent69b53720e92c1bdea854a2fc204477ddabfa902b (diff)
Merge tag 'for-linus-20190715' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd and clone3 fixes from Christian Brauner: "This contains a bugfix for CLONE_PIDFD when used with the legacy clone syscall, two fixes to ensure that syscall numbering and clone3 entrypoint implementations will stay consistent, and an update for the maintainers file: - The addition of clone3 broke CLONE_PIDFD for legacy clone on all architectures that use do_fork() directly instead of calling the clone syscall itself. (Fwiw, cleaning do_fork() up is on my todo.) The reason this happened was that during conversion of _do_fork() to use struct kernel_clone_args we missed that do_fork() is called directly by various architectures. This is fixed by making sure that the pidfd argument in struct kernel_clone_args is correctly initialized with the parent_tidptr argument passed down from do_fork(). Additionally, do_fork() missed a check to make CLONE_PIDFD and CLONE_PARENT_SETTID mutually exclusive just a clone() does. This is now fixed too. - When clone3() was introduced we skipped architectures that require special handling for fork-like syscalls. Their syscall tables did not contain any mention of clone3(). To make sure that Arnd's work to make syscall numbers on all architectures identical (minus alpha) was not for naught we are placing a comment in all syscall tables that do not yet implement clone3(). The comment makes it clear that 435 is reserved for clone3 and should not be used. - Also, this contains a patch to make the clone3() syscall definition in asm-generic/unist.h conditional on __ARCH_WANT_SYS_CLONE3. This lets us catch new architectures that implicitly make use of clone3 without setting __ARCH_WANT_SYS_CLONE3 which is a good indicator that they did not check whether it needs special treatment or not. - Finally, this contains a patch to add me as maintainer for pidfd stuff so people can start blaming me (more)" * tag 'for-linus-20190715' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: MAINTAINERS: add new entry for pidfd api unistd: protect clone3 via __ARCH_WANT_SYS_CLONE3 arch: mark syscall number 435 reserved for clone3 clone: fix CLONE_PIDFD support
-rw-r--r--MAINTAINERS11
-rw-r--r--arch/alpha/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/ia64/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/m68k/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/mips/kernel/syscalls/syscall_n32.tbl1
-rw-r--r--arch/mips/kernel/syscalls/syscall_n64.tbl1
-rw-r--r--arch/mips/kernel/syscalls/syscall_o32.tbl1
-rw-r--r--arch/parisc/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/powerpc/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/s390/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/sh/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/sparc/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/x86/ia32/sys_ia32.c4
-rw-r--r--include/linux/sched/task.h1
-rw-r--r--include/uapi/asm-generic/unistd.h2
-rw-r--r--kernel/fork.c17
16 files changed, 44 insertions, 2 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index 6debe6829716..afba8bf5d716 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12611,6 +12611,17 @@ F: arch/arm/boot/dts/picoxcell*
F: arch/arm/mach-picoxcell/
F: drivers/crypto/picoxcell*
+PIDFD API
+M: Christian Brauner <christian@brauner.io>
+L: linux-kernel@vger.kernel.org
+S: Maintained
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git
+F: samples/pidfd/
+F: tools/testing/selftests/pidfd/
+K: (?i)pidfd
+K: (?i)clone3
+K: \b(clone_args|kernel_clone_args)\b
+
PIN CONTROL SUBSYSTEM
M: Linus Walleij <linus.walleij@linaro.org>
L: linux-gpio@vger.kernel.org
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 1db9bbcfb84e..728fe028c02c 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -474,3 +474,4 @@
542 common fsmount sys_fsmount
543 common fspick sys_fspick
544 common pidfd_open sys_pidfd_open
+# 545 reserved for clone3
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index ecc44926737b..36d5faf4c86c 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -355,3 +355,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 9a3eb2558568..a88a285a0e5f 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -434,3 +434,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 97035e19ad03..c9c879ec9b6d 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -373,3 +373,4 @@
432 n32 fsmount sys_fsmount
433 n32 fspick sys_fspick
434 n32 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index d7292722d3b0..bbce9159caa1 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -349,3 +349,4 @@
432 n64 fsmount sys_fsmount
433 n64 fspick sys_fspick
434 n64 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index dba084c92f14..9653591428ec 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -422,3 +422,4 @@
432 o32 fsmount sys_fsmount
433 o32 fspick sys_fspick
434 o32 pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 5022b9e179c2..c7aadfef5386 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -431,3 +431,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index f2c3bda2d39f..3331749aab20 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -516,3 +516,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 6ebacfeaf853..a90d3e945445 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
432 common fsmount sys_fsmount sys_fsmount
433 common fspick sys_fspick sys_fspick
434 common pidfd_open sys_pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 834c9c7d79fa..b5ed26c4c005 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index c58e71f21129..8c8cc7537fb2 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -480,3 +480,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+# 435 reserved for clone3
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index 64a6c952091e..21790307121e 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -239,6 +239,7 @@ COMPAT_SYSCALL_DEFINE5(x86_clone, unsigned long, clone_flags,
{
struct kernel_clone_args args = {
.flags = (clone_flags & ~CSIGNAL),
+ .pidfd = parent_tidptr,
.child_tid = child_tidptr,
.parent_tid = parent_tidptr,
.exit_signal = (clone_flags & CSIGNAL),
@@ -246,5 +247,8 @@ COMPAT_SYSCALL_DEFINE5(x86_clone, unsigned long, clone_flags,
.tls = tls_val,
};
+ if (!legacy_clone_args_valid(&args))
+ return -EINVAL;
+
return _do_fork(&args);
}
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 109a0df5af39..0497091e40c1 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -89,6 +89,7 @@ extern void exit_files(struct task_struct *);
extern void exit_itimers(struct signal_struct *);
extern long _do_fork(struct kernel_clone_args *kargs);
+extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs);
extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
struct task_struct *fork_idle(int);
struct mm_struct *copy_init_mm(void);
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 9acfff0cd153..1be0e798e362 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -846,8 +846,10 @@ __SYSCALL(__NR_fsmount, sys_fsmount)
__SYSCALL(__NR_fspick, sys_fspick)
#define __NR_pidfd_open 434
__SYSCALL(__NR_pidfd_open, sys_pidfd_open)
+#ifdef __ARCH_WANT_SYS_CLONE3
#define __NR_clone3 435
__SYSCALL(__NR_clone3, sys_clone3)
+#endif
#undef __NR_syscalls
#define __NR_syscalls 436
diff --git a/kernel/fork.c b/kernel/fork.c
index dfa78985a6fd..d8ae0f1b4148 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2405,6 +2405,16 @@ long _do_fork(struct kernel_clone_args *args)
return nr;
}
+bool legacy_clone_args_valid(const struct kernel_clone_args *kargs)
+{
+ /* clone(CLONE_PIDFD) uses parent_tidptr to return a pidfd */
+ if ((kargs->flags & CLONE_PIDFD) &&
+ (kargs->flags & CLONE_PARENT_SETTID))
+ return false;
+
+ return true;
+}
+
#ifndef CONFIG_HAVE_COPY_THREAD_TLS
/* For compatibility with architectures that call do_fork directly rather than
* using the syscall entry points below. */
@@ -2416,6 +2426,7 @@ long do_fork(unsigned long clone_flags,
{
struct kernel_clone_args args = {
.flags = (clone_flags & ~CSIGNAL),
+ .pidfd = parent_tidptr,
.child_tid = child_tidptr,
.parent_tid = parent_tidptr,
.exit_signal = (clone_flags & CSIGNAL),
@@ -2423,6 +2434,9 @@ long do_fork(unsigned long clone_flags,
.stack_size = stack_size,
};
+ if (!legacy_clone_args_valid(&args))
+ return -EINVAL;
+
return _do_fork(&args);
}
#endif
@@ -2504,8 +2518,7 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
.tls = tls,
};
- /* clone(CLONE_PIDFD) uses parent_tidptr to return a pidfd */
- if ((clone_flags & CLONE_PIDFD) && (clone_flags & CLONE_PARENT_SETTID))
+ if (!legacy_clone_args_valid(&args))
return -EINVAL;
return _do_fork(&args);