From d5f20be7cab85e6e701751323eea77c7935ae522 Mon Sep 17 00:00:00 2001 From: Nicolas Iooss Date: Sun, 12 Oct 2014 13:02:11 +0200 Subject: um: Create asm/sections.h arch/um/kernel/dyn.lds.S and arch/um/kernel/uml.lds.S define some UML-specific symbols. These symbols are used in the kernel part of UML with extern declarations. Move these declarations to a new header, asm/sections.h, like other architectures do. Signed-off-by: Nicolas Iooss Signed-off-by: Richard Weinberger --- arch/um/kernel/physmem.c | 3 +-- arch/um/kernel/skas/mmu.c | 3 +-- arch/um/kernel/um_arch.c | 2 -- 3 files changed, 2 insertions(+), 6 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c index 9034fc8..249c9fe 100644 --- a/arch/um/kernel/physmem.c +++ b/arch/um/kernel/physmem.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -55,8 +56,6 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len, } } -extern int __syscall_stub_start; - /** * setup_physmem() - Setup physical memory for UML * @start: Start address of the physical kernel memory, diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index 94abdcc..2216edd 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -8,12 +8,11 @@ #include #include #include +#include #include #include #include -extern int __syscall_stub_start; - static int init_stub_pte(struct mm_struct *mm, unsigned long proc, unsigned long kernel) { diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index 07f798f..ffa185d 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -248,8 +248,6 @@ EXPORT_SYMBOL(end_iomem); #define MIN_VMALLOC (32 * 1024 * 1024) -extern char __binary_start; - int __init linux_main(int argc, char **argv) { unsigned long avail, diff; -- cgit v1.1 From 05eacfd00ccf239a24cfb409b084fa126c2e9468 Mon Sep 17 00:00:00 2001 From: Nicolas Iooss Date: Sun, 12 Oct 2014 13:02:12 +0200 Subject: um: Use char[] for linker script address declarations The linker script defines some variables which are declared either with type char[] in include/asm-generic/sections.h or with a meaningless integer type in arch/um/include/asm/sections.h. Fix this inconsistency by declaring every variable char[]. Signed-off-by: Nicolas Iooss Signed-off-by: Richard Weinberger --- arch/um/kernel/physmem.c | 4 ++-- arch/um/kernel/skas/mmu.c | 4 ++-- arch/um/kernel/um_arch.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c index 249c9fe..4c9861b 100644 --- a/arch/um/kernel/physmem.c +++ b/arch/um/kernel/physmem.c @@ -109,8 +109,8 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end, * Special kludge - This page will be mapped in to userspace processes * from physmem_fd, so it needs to be written out there. */ - os_seek_file(physmem_fd, __pa(&__syscall_stub_start)); - os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE); + os_seek_file(physmem_fd, __pa(__syscall_stub_start)); + os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE); os_fsync_file(physmem_fd); bootmap_size = init_bootmem(pfn, pfn + delta); diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index 2216edd..fda1deb 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -92,7 +92,7 @@ void uml_setup_stubs(struct mm_struct *mm) int err, ret; ret = init_stub_pte(mm, STUB_CODE, - (unsigned long) &__syscall_stub_start); + (unsigned long) __syscall_stub_start); if (ret) goto out; @@ -100,7 +100,7 @@ void uml_setup_stubs(struct mm_struct *mm) if (ret) goto out; - mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start); + mm->context.stub_pages[0] = virt_to_page(__syscall_stub_start); mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack); /* dup_mmap already holds mmap_sem */ diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c index ffa185d..16630e7 100644 --- a/arch/um/kernel/um_arch.c +++ b/arch/um/kernel/um_arch.c @@ -292,7 +292,7 @@ int __init linux_main(int argc, char **argv) physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); } - uml_physmem = (unsigned long) &__binary_start & PAGE_MASK; + uml_physmem = (unsigned long) __binary_start & PAGE_MASK; /* Reserve up to 4M after the current brk */ uml_reserved = ROUND_4M(brk_start) + (1 << 22); -- cgit v1.1 From a791b1565f828f926a54f1f5a612890ce0f00e6f Mon Sep 17 00:00:00 2001 From: Chen Gang Date: Sat, 4 Oct 2014 21:11:31 +0800 Subject: um: kernel: ksyms: Export symbol syscall() for fixing modpost issue syscall() is implemented in libc.so/a (e.g. for glibc, in "syscall.o"), so for normal ".o" files, it is undefined, neither can be found within kernel wide, so will break modpost. Since ".o" files is OK, can simply export 'syscall' symbol, let modpost know about that, then can fix this issue. The related error (with allmodconfig under um): MODPOST 1205 modules ERROR: "syscall" [fs/hostfs/hostfs.ko] undefined! Signed-off-by: Chen Gang Signed-off-by: Richard Weinberger --- arch/um/kernel/ksyms.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c index 543c047..e7780f3 100644 --- a/arch/um/kernel/ksyms.c +++ b/arch/um/kernel/ksyms.c @@ -42,3 +42,6 @@ EXPORT_SYMBOL(os_makedev); EXPORT_SYMBOL(add_sigio_fd); EXPORT_SYMBOL(ignore_sigio_fd); EXPORT_SYMBOL(sigio_broken); + +extern long int syscall (long int __sysno, ...); +EXPORT_SYMBOL(syscall); -- cgit v1.1 From 89520d999683cb945d7540efd0944b3af2db9a54 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sun, 31 May 2015 13:11:19 +0200 Subject: um: Move syscall() declaration into os.h Signed-off-by: Richard Weinberger --- arch/um/kernel/ksyms.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c index e7780f3..232b2230 100644 --- a/arch/um/kernel/ksyms.c +++ b/arch/um/kernel/ksyms.c @@ -43,5 +43,4 @@ EXPORT_SYMBOL(add_sigio_fd); EXPORT_SYMBOL(ignore_sigio_fd); EXPORT_SYMBOL(sigio_broken); -extern long int syscall (long int __sysno, ...); EXPORT_SYMBOL(syscall); -- cgit v1.1 From f8d65d27e677da0ce33de570e3068308a77ed2b1 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Tue, 12 May 2015 00:17:28 +0200 Subject: um: Rework uaccess code Rework UML's uaccess code to reuse as much as possible from asm-generic/uaccess.c. Signed-off-by: Richard Weinberger --- arch/um/kernel/skas/uaccess.c | 47 ++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 30 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c index 4ffb644..85ac8ad 100644 --- a/arch/um/kernel/skas/uaccess.c +++ b/arch/um/kernel/skas/uaccess.c @@ -87,10 +87,10 @@ static int do_op_one_page(unsigned long addr, int len, int is_write, return n; } -static int buffer_op(unsigned long addr, int len, int is_write, - int (*op)(unsigned long, int, void *), void *arg) +static long buffer_op(unsigned long addr, int len, int is_write, + int (*op)(unsigned long, int, void *), void *arg) { - int size, remain, n; + long size, remain, n; size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len); remain = len; @@ -139,18 +139,16 @@ static int copy_chunk_from_user(unsigned long from, int len, void *arg) return 0; } -int copy_from_user(void *to, const void __user *from, int n) +long __copy_from_user(void *to, const void __user *from, unsigned long n) { if (segment_eq(get_fs(), KERNEL_DS)) { memcpy(to, (__force void*)from, n); return 0; } - return access_ok(VERIFY_READ, from, n) ? - buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to): - n; + return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to); } -EXPORT_SYMBOL(copy_from_user); +EXPORT_SYMBOL(__copy_from_user); static int copy_chunk_to_user(unsigned long to, int len, void *arg) { @@ -161,18 +159,16 @@ static int copy_chunk_to_user(unsigned long to, int len, void *arg) return 0; } -int copy_to_user(void __user *to, const void *from, int n) +long __copy_to_user(void __user *to, const void *from, unsigned long n) { if (segment_eq(get_fs(), KERNEL_DS)) { memcpy((__force void *) to, from, n); return 0; } - return access_ok(VERIFY_WRITE, to, n) ? - buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) : - n; + return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from); } -EXPORT_SYMBOL(copy_to_user); +EXPORT_SYMBOL(__copy_to_user); static int strncpy_chunk_from_user(unsigned long from, int len, void *arg) { @@ -188,9 +184,9 @@ static int strncpy_chunk_from_user(unsigned long from, int len, void *arg) return 0; } -int strncpy_from_user(char *dst, const char __user *src, int count) +long __strncpy_from_user(char *dst, const char __user *src, long count) { - int n; + long n; char *ptr = dst; if (segment_eq(get_fs(), KERNEL_DS)) { @@ -198,16 +194,13 @@ int strncpy_from_user(char *dst, const char __user *src, int count) return strnlen(dst, count); } - if (!access_ok(VERIFY_READ, src, 1)) - return -EFAULT; - n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user, &ptr); if (n != 0) return -EFAULT; return strnlen(dst, count); } -EXPORT_SYMBOL(strncpy_from_user); +EXPORT_SYMBOL(__strncpy_from_user); static int clear_chunk(unsigned long addr, int len, void *unused) { @@ -215,22 +208,16 @@ static int clear_chunk(unsigned long addr, int len, void *unused) return 0; } -int __clear_user(void __user *mem, int len) -{ - return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL); -} - -int clear_user(void __user *mem, int len) +unsigned long __clear_user(void __user *mem, unsigned long len) { if (segment_eq(get_fs(), KERNEL_DS)) { memset((__force void*)mem, 0, len); return 0; } - return access_ok(VERIFY_WRITE, mem, len) ? - buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len; + return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL); } -EXPORT_SYMBOL(clear_user); +EXPORT_SYMBOL(__clear_user); static int strnlen_chunk(unsigned long str, int len, void *arg) { @@ -244,7 +231,7 @@ static int strnlen_chunk(unsigned long str, int len, void *arg) return 0; } -int strnlen_user(const void __user *str, int len) +long __strnlen_user(const void __user *str, long len) { int count = 0, n; @@ -256,4 +243,4 @@ int strnlen_user(const void __user *str, int len) return count + 1; return 0; } -EXPORT_SYMBOL(strnlen_user); +EXPORT_SYMBOL(__strnlen_user); -- cgit v1.1 From d2313084e2c3488e254796617fcda45d69731b21 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sun, 31 May 2015 19:21:51 +0200 Subject: um: Catch unprotected user memory access If the kernel tries to access user memory without copy_from_user() a trap will happen as kernel and userspace run in different processes on the host side. Currently this special page fault cannot be resolved and will happen over and over again. As result UML will lockup. This patch allows the page fault code to detect that situation and causes a panic() such that the root cause of the unprotected memory access can be found and fixed. Signed-off-by: Richard Weinberger --- arch/um/kernel/trap.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 8e4daf4..34b633e 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -219,6 +219,11 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, show_regs(container_of(regs, struct pt_regs, regs)); panic("Segfault with no mm"); } + else if (!is_user && address < TASK_SIZE) { + show_regs(container_of(regs, struct pt_regs, regs)); + panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx", + address, ip); + } if (SEGV_IS_FIXABLE(&fi)) err = handle_page_fault(address, ip, is_write, is_user, -- cgit v1.1 From 5334cdae407a5778a297a98a75ca61140e37ebfa Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Sun, 31 May 2015 22:59:03 +0200 Subject: um: Handle tracehook_report_syscall_entry() result tracehook_report_syscall_entry() is allowed to fail, in case of failure we have to abort the current syscall. Signed-off-by: Richard Weinberger --- arch/um/kernel/ptrace.c | 6 +++--- arch/um/kernel/skas/syscall.c | 6 +++++- 2 files changed, 8 insertions(+), 4 deletions(-) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c index 174ee50..cac2ea0 100644 --- a/arch/um/kernel/ptrace.c +++ b/arch/um/kernel/ptrace.c @@ -131,7 +131,7 @@ static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs, * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check */ -void syscall_trace_enter(struct pt_regs *regs) +int syscall_trace_enter(struct pt_regs *regs) { audit_syscall_entry(UPT_SYSCALL_NR(®s->regs), UPT_SYSCALL_ARG1(®s->regs), @@ -140,9 +140,9 @@ void syscall_trace_enter(struct pt_regs *regs) UPT_SYSCALL_ARG4(®s->regs)); if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return; + return 0; - tracehook_report_syscall_entry(regs); + return tracehook_report_syscall_entry(regs); } void syscall_trace_leave(struct pt_regs *regs) diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index c0681e0..d9ec006 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -18,7 +18,10 @@ void handle_syscall(struct uml_pt_regs *r) long result; int syscall; - syscall_trace_enter(regs); + if (syscall_trace_enter(regs)) { + result = -ENOSYS; + goto out; + } /* * This should go in the declaration of syscall, but when I do that, @@ -34,6 +37,7 @@ void handle_syscall(struct uml_pt_regs *r) result = -ENOSYS; else result = EXECUTE_SYSCALL(syscall, regs); +out: PT_REGS_SET_SYSCALL_RETURN(regs, result); syscall_trace_leave(regs); -- cgit v1.1 From da028d5e5463dabb6ede2f5e3f6cced1283988cc Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Thu, 25 Jun 2015 22:44:11 +0200 Subject: um: Don't pollute kernel namespace with uapi Don't include ptrace uapi stuff in arch headers, it will pollute the kernel namespace and conflict with existing stuff. In this case it fixes clashes with common names like R8. Signed-off-by: Richard Weinberger --- arch/um/kernel/ptrace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/um/kernel') diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c index cac2ea0..6a826cb 100644 --- a/arch/um/kernel/ptrace.c +++ b/arch/um/kernel/ptrace.c @@ -8,6 +8,7 @@ #include #include #include +#include void user_enable_single_step(struct task_struct *child) { -- cgit v1.1