[2/5] exec: simplify the compat syscall handling

Message ID	20200627072704.2447163-3-hch@lst.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=CU/q=AI=lists.infradead.org=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 29A1C2081A From: Christoph Hellwig <hch@lst.de> To: Al Viro <viro@zeniv.linux.org.uk> Subject: [PATCH 2/5] exec: simplify the compat syscall handling Date: Sat, 27 Jun 2020 09:27:01 +0200 Message-Id: <20200627072704.2447163-3-hch@lst.de> In-Reply-To: <20200627072704.2447163-1-hch@lst.de> References: <20200627072704.2447163-1-hch@lst.de> MIME-Version: 1.0 Precedence: list Cc: linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-parisc@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>, Brian Gerst <brgerst@gmail.com>, x86@kernel.org, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Luis Chamberlain <mcgrof@kernel.org>, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org
Series	[1/5] exec: cleanup the execve wrappers \| expand [1/5] exec: cleanup the execve wrappers [2/5] exec: simplify the compat syscall handling [3/5] exec: cleanup the count() function [4/5] exec: split prepare_arg_pages [5/5] exec: add a kernel_execveat helper

diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index 6d95d0c8bf2f47..141f5d2ff1c34f 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -33,7 +33,7 @@ __SYSCALL(__NR_link, sys_link) #define __NR_unlink 10 __SYSCALL(__NR_unlink, sys_unlink) #define __NR_execve 11 -__SYSCALL(__NR_execve, compat_sys_execve) +__SYSCALL(__NR_execve, sys_execve) #define __NR_chdir 12 __SYSCALL(__NR_chdir, sys_chdir) /* 13 was sys_time */ @@ -785,7 +785,7 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create) #define __NR_bpf 386 __SYSCALL(__NR_bpf, sys_bpf) #define __NR_execveat 387 -__SYSCALL(__NR_execveat, compat_sys_execveat) +__SYSCALL(__NR_execveat, sys_execveat) #define __NR_userfaultfd 388 __SYSCALL(__NR_userfaultfd, sys_userfaultfd) #define __NR_membarrier 389 diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index f777141f52568f..e861b5ab7179c9 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -64,7 +64,7 @@ 54 n32 getsockopt compat_sys_getsockopt 55 n32 clone __sys_clone 56 n32 fork __sys_fork -57 n32 execve compat_sys_execve +57 n32 execve sys_execve 58 n32 exit sys_exit 59 n32 wait4 compat_sys_wait4 60 n32 kill sys_kill @@ -328,7 +328,7 @@ 317 n32 getrandom sys_getrandom 318 n32 memfd_create sys_memfd_create 319 n32 bpf sys_bpf -320 n32 execveat compat_sys_execveat +320 n32 execveat sys_execveat 321 n32 userfaultfd sys_userfaultfd 322 n32 membarrier sys_membarrier 323 n32 mlock2 sys_mlock2 diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index 13280625d312e9..bba80f74e9968e 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -18,7 +18,7 @@ 8 o32 creat sys_creat 9 o32 link sys_link 10 o32 unlink sys_unlink -11 o32 execve sys_execve compat_sys_execve +11 o32 execve sys_execve 12 o32 chdir sys_chdir 13 o32 time sys_time32 14 o32 mknod sys_mknod @@ -367,7 +367,7 @@ 353 o32 getrandom sys_getrandom 354 o32 memfd_create sys_memfd_create 355 o32 bpf sys_bpf -356 o32 execveat sys_execveat compat_sys_execveat +356 o32 execveat sys_execveat 357 o32 userfaultfd sys_userfaultfd 358 o32 membarrier sys_membarrier 359 o32 mlock2 sys_mlock2 diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index 5a758fa6ec5242..23fa0d0edf3384 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -18,7 +18,7 @@ 8 common creat sys_creat 9 common link sys_link 10 common unlink sys_unlink -11 common execve sys_execve compat_sys_execve +11 common execve sys_execve 12 common chdir sys_chdir 13 32 time sys_time32 13 64 time sys_time @@ -385,7 +385,7 @@ 339 common getrandom sys_getrandom 340 common memfd_create sys_memfd_create 341 common bpf sys_bpf -342 common execveat sys_execveat compat_sys_execveat +342 common execveat sys_execveat 343 common membarrier sys_membarrier 344 common userfaultfd sys_userfaultfd 345 common mlock2 sys_mlock2 diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index f833a319082247..c52cdab89dc0ae 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -20,7 +20,7 @@ 8 common creat sys_creat 9 common link sys_link 10 common unlink sys_unlink -11 nospu execve sys_execve compat_sys_execve +11 nospu execve sys_execve 12 common chdir sys_chdir 13 32 time sys_time32 13 64 time sys_time @@ -460,7 +460,7 @@ 359 common getrandom sys_getrandom 360 common memfd_create sys_memfd_create 361 common bpf sys_bpf -362 nospu execveat sys_execveat compat_sys_execveat +362 nospu execveat sys_execveat 363 32 switch_endian sys_ni_syscall 363 64 switch_endian sys_switch_endian 363 spu switch_endian sys_ni_syscall diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index bfdcb763395735..bd2275db2026ea 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -18,7 +18,7 @@ 8 common creat sys_creat sys_creat 9 common link sys_link sys_link 10 common unlink sys_unlink sys_unlink -11 common execve sys_execve compat_sys_execve +11 common execve sys_execve sys_execve 12 common chdir sys_chdir sys_chdir 13 32 time - sys_time32 14 common mknod sys_mknod sys_mknod @@ -361,7 +361,7 @@ 351 common bpf sys_bpf sys_bpf 352 common s390_pci_mmio_write sys_s390_pci_mmio_write sys_s390_pci_mmio_write 353 common s390_pci_mmio_read sys_s390_pci_mmio_read sys_s390_pci_mmio_read -354 common execveat sys_execveat compat_sys_execveat +354 common execveat sys_execveat sys_execveat 355 common userfaultfd sys_userfaultfd sys_userfaultfd 356 common membarrier sys_membarrier sys_membarrier 357 common recvmmsg sys_recvmmsg compat_sys_recvmmsg_time32 diff --git a/arch/sparc/kernel/syscalls.S b/arch/sparc/kernel/syscalls.S index db42b4fb370844..70463972152a92 100644 --- a/arch/sparc/kernel/syscalls.S +++ b/arch/sparc/kernel/syscalls.S @@ -16,12 +16,12 @@ sys64_execveat: sunos_execv: mov %g0, %o2 sys32_execve: - set compat_sys_execve, %g1 + set sys_execve, %g1 jmpl %g1, %g0 flushw sys32_execveat: - set compat_sys_execveat, %g1 + set sys_execveat, %g1 jmpl %g1, %g0 flushw #endif diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c index 3d8d70d3896c87..c9f39900a93b96 100644 --- a/arch/x86/entry/syscall_x32.c +++ b/arch/x86/entry/syscall_x32.c @@ -8,6 +8,13 @@ #include <asm/unistd.h> #include <asm/syscall.h> +/* + * Reuse the 64-bit entry points for the x32 versions that occupy different + * slots in the syscall table. + */ +#define __x32_sys_execve __x64_sys_execve +#define __x32_sys_execveat __x64_sys_execveat + #define __SYSCALL_64(nr, sym) #define __SYSCALL_X32(nr, sym) extern long __x32_##sym(const struct pt_regs *); diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index d8f8a1a69ed11f..2b1eccd3f8f697 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -22,7 +22,7 @@ 8 i386 creat sys_creat 9 i386 link sys_link 10 i386 unlink sys_unlink -11 i386 execve sys_execve compat_sys_execve +11 i386 execve sys_execve 12 i386 chdir sys_chdir 13 i386 time sys_time32 14 i386 mknod sys_mknod @@ -369,7 +369,7 @@ 355 i386 getrandom sys_getrandom 356 i386 memfd_create sys_memfd_create 357 i386 bpf sys_bpf -358 i386 execveat sys_execveat compat_sys_execveat +358 i386 execveat sys_execveat 359 i386 socket sys_socket 360 i386 socketpair sys_socketpair 361 i386 bind sys_bind diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 78847b32e1370f..cb3fce6ed63ebf 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -375,7 +375,7 @@ 517 x32 recvfrom compat_sys_recvfrom 518 x32 sendmsg compat_sys_sendmsg 519 x32 recvmsg compat_sys_recvmsg -520 x32 execve compat_sys_execve +520 x32 execve sys_execve 521 x32 ptrace compat_sys_ptrace 522 x32 rt_sigpending compat_sys_rt_sigpending 523 x32 rt_sigtimedwait compat_sys_rt_sigtimedwait_time64 @@ -400,6 +400,6 @@ 542 x32 getsockopt compat_sys_getsockopt 543 x32 io_setup compat_sys_io_setup 544 x32 io_submit compat_sys_io_submit -545 x32 execveat compat_sys_execveat +545 x32 execveat sys_execveat 546 x32 preadv2 compat_sys_preadv64v2 547 x32 pwritev2 compat_sys_pwritev64v2 diff --git a/fs/exec.c b/fs/exec.c index 354fdaa536ae7d..4e5db0e35797a5 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -386,47 +386,34 @@ static int bprm_mm_init(struct linux_binprm *bprm) return err; } -struct user_arg_ptr { -#ifdef CONFIG_COMPAT - bool is_compat; -#endif - union { - const char __user *const __user *native; -#ifdef CONFIG_COMPAT - const compat_uptr_t __user *compat; -#endif - } ptr; -}; - -static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) +static const char __user * +get_user_arg_ptr(const char __user *const __user *argv, int nr) { - const char __user *native; - -#ifdef CONFIG_COMPAT - if (unlikely(argv.is_compat)) { + if (in_compat_syscall()) { + const compat_uptr_t __user *compat_argv = + compat_ptr((unsigned long)argv); compat_uptr_t compat; - if (get_user(compat, argv.ptr.compat + nr)) + if (get_user(compat, compat_argv + nr)) return ERR_PTR(-EFAULT); - return compat_ptr(compat); - } -#endif - - if (get_user(native, argv.ptr.native + nr)) - return ERR_PTR(-EFAULT); + } else { + const char __user *native; - return native; + if (get_user(native, argv + nr)) + return ERR_PTR(-EFAULT); + return native; + } } /* * count() counts the number of strings in array ARGV. */ -static int count(struct user_arg_ptr argv, int max) +static int count(const char __user *const __user *argv, int max) { int i = 0; - if (argv.ptr.native != NULL) { + if (argv) { for (;;) { const char __user *p = get_user_arg_ptr(argv, i); @@ -449,7 +436,8 @@ static int count(struct user_arg_ptr argv, int max) } static int prepare_arg_pages(struct linux_binprm *bprm, - struct user_arg_ptr argv, struct user_arg_ptr envp) + const char __user *const __user *argv, + const char __user *const __user *envp) { unsigned long limit, ptr_size; @@ -497,7 +485,7 @@ static int prepare_arg_pages(struct linux_binprm *bprm, * processes's memory to the new process's stack. The call to get_user_pages() * ensures the destination page is created and not swapped out. */ -static int copy_strings(int argc, struct user_arg_ptr argv, +static int copy_strings(int argc, const char __user *const __user *argv, struct linux_binprm *bprm) { struct page *kmapped_page = NULL; @@ -1815,10 +1803,10 @@ static int exec_binprm(struct linux_binprm *bprm) return 0; } -static int __do_execveat(int fd, struct filename *filename, - struct user_arg_ptr argv, - struct user_arg_ptr envp, - int flags, struct file *file) +int do_execveat(int fd, struct filename *filename, + const char __user *const __user *argv, + const char __user *const __user *envp, + int flags, struct file *file) { char *pathbuf = NULL; struct linux_binprm *bprm; @@ -1969,17 +1957,6 @@ static int __do_execveat(int fd, struct filename *filename, return retval; } -int do_execveat(int fd, struct filename *filename, - const char __user *const __user *__argv, - const char __user *const __user *__envp, - int flags, struct file *file) -{ - struct user_arg_ptr argv = { .ptr.native = __argv }; - struct user_arg_ptr envp = { .ptr.native = __envp }; - - return __do_execveat(fd, filename, argv, envp, flags, file); -} - void set_binfmt(struct linux_binfmt *new) { struct mm_struct *mm = current->mm; @@ -2023,41 +2000,3 @@ SYSCALL_DEFINE5(execveat, return do_execveat(fd, name, argv, envp, flags, NULL); } - -#ifdef CONFIG_COMPAT -static int do_compat_execve(int fd, struct filename *filename, - const compat_uptr_t __user *__argv, - const compat_uptr_t __user *__envp, - int flags) -{ - struct user_arg_ptr argv = { - .is_compat = true, - .ptr.compat = __argv, - }; - struct user_arg_ptr envp = { - .is_compat = true, - .ptr.compat = __envp, - }; - - return __do_execveat(fd, filename, argv, envp, flags, NULL); -} - -COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, - const compat_uptr_t __user *, argv, - const compat_uptr_t __user *, envp) -{ - return do_compat_execve(AT_FDCWD, getname(filename), argv, envp, 0); -} - -COMPAT_SYSCALL_DEFINE5(execveat, int, fd, - const char __user *, filename, - const compat_uptr_t __user *, argv, - const compat_uptr_t __user *, envp, - int, flags) -{ - int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; - struct filename *name = getname_flags(filename, lookup_flags, NULL); - - return do_compat_execve(fd, name, argv, envp, flags); -} -#endif diff --git a/include/linux/compat.h b/include/linux/compat.h index e90100c0de72e4..5e8f6a588e0d43 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -752,10 +752,6 @@ asmlinkage long compat_sys_recvmsg(int fd, struct compat_msghdr __user *msg, asmlinkage long compat_sys_keyctl(u32 option, u32 arg2, u32 arg3, u32 arg4, u32 arg5); -/* arch/example/kernel/sys_example.c */ -asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr_t __user *argv, - const compat_uptr_t __user *envp); - /* mm/fadvise.c: No generic prototype for fadvise64_64 */ /* mm/, CONFIG_MMU only */ @@ -806,9 +802,6 @@ asmlinkage ssize_t compat_sys_process_vm_writev(compat_pid_t pid, const struct compat_iovec __user *lvec, compat_ulong_t liovcnt, const struct compat_iovec __user *rvec, compat_ulong_t riovcnt, compat_ulong_t flags); -asmlinkage long compat_sys_execveat(int dfd, const char __user *filename, - const compat_uptr_t __user *argv, - const compat_uptr_t __user *envp, int flags); asmlinkage ssize_t compat_sys_preadv2(compat_ulong_t fd, const struct compat_iovec __user *vec, compat_ulong_t vlen, u32 pos_low, u32 pos_high, rwf_t flags); diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index f4a01305d9a65c..c639d04a094b8b 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -640,7 +640,7 @@ __SC_COMP(__NR_keyctl, sys_keyctl, compat_sys_keyctl) #define __NR_clone 220 __SYSCALL(__NR_clone, sys_clone) #define __NR_execve 221 -__SC_COMP(__NR_execve, sys_execve, compat_sys_execve) +__SYSCALL(__NR_execve, sys_execve) #define __NR3264_mmap 222 __SC_3264(__NR3264_mmap, sys_mmap2, sys_mmap) @@ -751,7 +751,7 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create) #define __NR_bpf 280 __SYSCALL(__NR_bpf, sys_bpf) #define __NR_execveat 281 -__SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat) +__SYSCALL(__NR_execveat, sys_execveat) #define __NR_userfaultfd 282 __SYSCALL(__NR_userfaultfd, sys_userfaultfd) #define __NR_membarrier 283 diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h index f4a01305d9a65c..c639d04a094b8b 100644 --- a/tools/include/uapi/asm-generic/unistd.h +++ b/tools/include/uapi/asm-generic/unistd.h @@ -640,7 +640,7 @@ __SC_COMP(__NR_keyctl, sys_keyctl, compat_sys_keyctl) #define __NR_clone 220 __SYSCALL(__NR_clone, sys_clone) #define __NR_execve 221 -__SC_COMP(__NR_execve, sys_execve, compat_sys_execve) +__SYSCALL(__NR_execve, sys_execve) #define __NR3264_mmap 222 __SC_3264(__NR3264_mmap, sys_mmap2, sys_mmap) @@ -751,7 +751,7 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create) #define __NR_bpf 280 __SYSCALL(__NR_bpf, sys_bpf) #define __NR_execveat 281 -__SC_COMP(__NR_execveat, sys_execveat, compat_sys_execveat) +__SYSCALL(__NR_execveat, sys_execveat) #define __NR_userfaultfd 282 __SYSCALL(__NR_userfaultfd, sys_userfaultfd) #define __NR_membarrier 283 diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl index 35b61bfc1b1ae9..42bf8b461a0ed6 100644 --- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl +++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl @@ -18,7 +18,7 @@ 8 common creat sys_creat 9 common link sys_link 10 common unlink sys_unlink -11 nospu execve sys_execve compat_sys_execve +11 nospu execve sys_execve sys_execve 12 common chdir sys_chdir 13 32 time sys_time32 13 64 time sys_time @@ -454,7 +454,7 @@ 359 common getrandom sys_getrandom 360 common memfd_create sys_memfd_create 361 common bpf sys_bpf -362 nospu execveat sys_execveat compat_sys_execveat +362 nospu execveat sys_execveat sys_execveat 363 32 switch_endian sys_ni_syscall 363 64 switch_endian ppc_switch_endian 363 spu switch_endian sys_ni_syscall diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl index b38d48464368dc..f3c16f2d9746ac 100644 --- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl +++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl @@ -18,7 +18,7 @@ 8 common creat sys_creat compat_sys_creat 9 common link sys_link compat_sys_link 10 common unlink sys_unlink compat_sys_unlink -11 common execve sys_execve compat_sys_execve +11 common execve sys_execve sys_execve 12 common chdir sys_chdir compat_sys_chdir 13 32 time - compat_sys_time 14 common mknod sys_mknod compat_sys_mknod @@ -361,7 +361,7 @@ 351 common bpf sys_bpf compat_sys_bpf 352 common s390_pci_mmio_write sys_s390_pci_mmio_write compat_sys_s390_pci_mmio_write 353 common s390_pci_mmio_read sys_s390_pci_mmio_read compat_sys_s390_pci_mmio_read -354 common execveat sys_execveat compat_sys_execveat +354 common execveat sys_execveat sys_execveat 355 common userfaultfd sys_userfaultfd sys_userfaultfd 356 common membarrier sys_membarrier sys_membarrier 357 common recvmmsg sys_recvmmsg compat_sys_recvmmsg diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl index 78847b32e1370f..cb3fce6ed63ebf 100644 --- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl +++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl @@ -375,7 +375,7 @@ 517 x32 recvfrom compat_sys_recvfrom 518 x32 sendmsg compat_sys_sendmsg 519 x32 recvmsg compat_sys_recvmsg -520 x32 execve compat_sys_execve +520 x32 execve sys_execve 521 x32 ptrace compat_sys_ptrace 522 x32 rt_sigpending compat_sys_rt_sigpending 523 x32 rt_sigtimedwait compat_sys_rt_sigtimedwait_time64 @@ -400,6 +400,6 @@ 542 x32 getsockopt compat_sys_getsockopt 543 x32 io_setup compat_sys_io_setup 544 x32 io_submit compat_sys_io_submit -545 x32 execveat compat_sys_execveat +545 x32 execveat sys_execveat 546 x32 preadv2 compat_sys_preadv64v2 547 x32 pwritev2 compat_sys_pwritev64v2

[2/5] exec: simplify the compat syscall handling

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