LKML Archive on lore.kernel.org help / color / Atom feed

* a.out coredumping: fix or delete? @ 2019-03-01 23:57 Jann Horn 2019-03-03 1:09 ` Andy Lutomirski 2019-03-05 9:19 ` Borislav Petkov 0 siblings, 2 replies; 42+ messages in thread From: Jann Horn @ 2019-03-01 23:57 UTC (permalink / raw) To: Al Viro Cc: Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API In theory, Linux can dump cores for a.out binaries. In practice, that code is pretty bitrotten and buggy. Does anyone want that code so much that they'd like to fix it, or can we just delete it? Here's a shell script that will give you a minimal a.out binary that Linux will execute (and that then segfaults immediately because it has no executable pages mapped): ============== #!/bin/bash ( # a_info: magic=OMAGIC printf '\x07\x01' # a_info: machtype=M_386 printf '\x64' # a_info: flags=0 printf '\x00' # a_text, a_data, a_bss, a_syms: 0 printf '\x00\x00\x00\x00' printf '\x00\x00\x00\x00' printf '\x00\x00\x00\x00' printf '\x00\x00\x00\x00' # a_entry: 0x42424242 printf '\x42\x42\x42\x42' # a_trsize, a_drsize: 0 printf '\x00\x00\x00\x00' printf '\x00\x00\x00\x00' ) > aout_binary chmod +x aout_binary ============== You need a kernel with CONFIG_IA32_AOUT enabled (for x86-64) or with CONFIG_BINFMT_AOUT enabled (for 32-bit x86). If aout is built as a module, you have to manually load it with "modprobe binfmt_aout", because even though there is binfmt autoloading code in the kernel, no aliases are set up for any binfmts. On a Debian 9 system with a 4.9 stable kernel, if you try to run this a.out program with core dumps enabled ("ulimit -c unlimited") a few times, the kernel oopses: ============== [ 2659.912016] aout_binary[978]: segfault at 42424242 ip 42424242 sp bfffe4e0 error 14 [ 2659.912318] BUG: unable to handle kernel paging request at bffff000 [ 2659.912336] IP: [<d030bd14>] memcpy+0x14/0x30 [ 2659.912364] *pdpt = 00000000367f7001 *pde = 000000007d0d1067 [ 2659.912368] Oops: 0000 [#1] SMP [ 2659.912377] Modules linked in: binfmt_aout [...] [ 2659.912421] CPU: 0 PID: 978 Comm: aout_binary Not tainted 4.9.0-8-686-pae #1 Debian 4.9.144-3.1 [ 2659.912422] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 2659.912424] task: f30e2000 task.stack: f470a000 [ 2659.912428] EIP: 0060:[<d030bd14>] EFLAGS: 00010206 CPU: 0 [ 2659.912430] EIP is at memcpy+0x14/0x30 [ 2659.912431] EAX: fffba000 EBX: 00001000 ECX: 00000400 EDX: bffff000 [ 2659.912433] ESI: bffff000 EDI: fffba000 EBP: f470bab0 ESP: f470baa4 [ 2659.912434] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 2659.912436] CR0: 80050033 CR2: bffff000 CR3: 346ad4e0 CR4: 001406f0 [ 2659.912442] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 2659.912444] DR6: fffe0ff0 DR7: 00000400 [ 2659.912445] Stack: [ 2659.912446] f470bbf0 bffff000 00001000 00001000 d03111a2 f470bb28 00003000 00000000 [ 2659.912449] fffbb000 f470bc10 fffba000 6721debb 00001000 00002000 00000000 f470bb40 [ 2659.912452] d016cd10 00001000 00000000 00001000 00000001 f470bb28 f470bb2c 00001000 [ 2659.912456] Call Trace: [ 2659.912475] [<d03111a2>] ? iov_iter_copy_from_user_atomic+0x1a2/0x230 [ 2659.912488] [<d016cd10>] ? generic_perform_write+0xe0/0x1d0 [ 2659.912492] [<d016ef52>] ? __generic_file_write_iter+0x192/0x1f0 [ 2659.912501] [<d0217c67>] ? __find_get_block+0xc7/0x250 [ 2659.912512] [<f8680496>] ? ext4_file_write_iter+0x86/0x460 [ext4] [ 2659.912514] [<f85c7050>] ? crc32c_intel_init+0x20/0x20 [crc32c_intel] [ 2659.912517] [<d021816c>] ? __getblk_gfp+0x2c/0x310 [ 2659.912523] [<d01e12bc>] ? generic_file_llseek_size+0x13c/0x1e0 [ 2659.912525] [<d01e1eac>] ? new_sync_write+0xcc/0x130 [ 2659.912527] [<d01e1faf>] ? __kernel_write+0x4f/0x100 [ 2659.912537] [<d023b382>] ? dump_emit+0x92/0xe0 [ 2659.912539] [<f86fead5>] ? aout_core_dump+0x2a5/0x2f1 [binfmt_aout] [ 2659.912542] [<d023bb43>] ? do_coredump+0x4d3/0xde0 [...] [ 2659.912618] Code: 58 2b 43 50 88 43 4e 5b 5d c3 90 8d 74 26 00 e8 43 fb ff ff eb e8 90 55 89 e5 57 56 53 3e 8d 74 26 00 89 cb 89 c7 c1 e9 02 89 d6 <f3> a5 89 d9 83 e1 03 74 02 f3 a4 5b 5e 5f 5d c3 8d b6 00 00 00 [ 2659.912639] EIP: [<d030bd14>] [ 2659.912641] memcpy+0x14/0x30 [ 2659.912642] SS:ESP 0068:f470baa4 [ 2659.912643] CR2: 00000000bffff000 [ 2659.912645] ---[ end trace 6413c918c629c657 ]--- ============== The problem is that since 43a5d548eb594, aout_core_dump() essentially calls __kernel_write() on a userspace address, which then causes iov_iter_init() to decide based on uaccess_kernel() that it should use ITER_KVEC and access the userspace memory with memcpy(). If you try to reproduce this on a 64-bit system with a master branch kernel, it doesn't work. But that's because that code is even more broken: The userspace stack pointer is something like 0xffffc4c8, but fill_dump() for some reason assumes that top-of-stack is at 0xc0000000, causing it to not even attempt to dump the stack: if (dump->start_stack < 0xc0000000) { unsigned long tmp; tmp = (unsigned long) (0xc0000000 - dump->start_stack); dump->u_ssize = tmp >> PAGE_SHIFT; } You can reproduce the oops if you use gdb to move the stack pointer down below 0xc0000000: ============== user@debian:~/aout$ ulimit -c unlimited user@debian:~/aout$ gdb ./aout_binary [...] (gdb) break *0x42424242 Breakpoint 1 at 0x42424242 (gdb) run Starting program: /home/user/aout/aout_binary [...] (gdb) p/x $sp $1 = 0xffffcdcc (gdb) set $sp=0x80000000 (gdb) detach Detaching from p[ 94.987218] aout_binary[1079]: segfault at 42424242 ip 0000000042424242 sp 0000000080000000 error 14 rogram: /home/us[ 94.989368] Code: Bad RIP value. er/aout/aout_binary, process 1079 (gdb) [ 94.991341] ================================================================== [ 94.993463] BUG: KASAN: user-memory-access in iov_iter_copy_from_user_atomic+0x23d/0x530 [ 94.995465] Read of size 4096 at addr 0000000080000000 by task aout_binary/1079 [ 94.997069] [ 94.997417] CPU: 4 PID: 1079 Comm: aout_binary Not tainted 5.0.0-rc8 #292 [ 94.998942] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 95.000809] Call Trace: [ 95.001412] dump_stack+0x71/0xab [...] [ 95.004628] kasan_report+0x176/0x192 [...] [ 95.006746] memcpy+0x1f/0x50 [ 95.007433] iov_iter_copy_from_user_atomic+0x23d/0x530 [...] [ 95.009459] generic_perform_write+0x1a1/0x2d0 [...] [ 95.013166] __generic_file_write_iter+0x264/0x2a0 [ 95.014242] ext4_file_write_iter+0x3a4/0x680 [...] [ 95.027234] __vfs_write+0x294/0x3b0 [...] [ 95.032673] __kernel_write+0x91/0x190 [ 95.033540] dump_emit+0x131/0x1d0 [...] [ 95.076087] Disabling lock debugging due to kernel taint [ 95.077287] BUG: unable to handle kernel paging request at 0000000080000000 [ 95.078812] #PF error: [normal kernel read fault] [ 95.079845] PGD 1e0629067 P4D 1e0629067 PUD 0 [ 95.080831] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN [...] ============== Also, the non-compat version of the coredump code looks like it leaks some kernel memory into the coredump through "struct user". I don't think anyone's going to care much, given that it looks like on distro kernels, you won't usually be able to load a.out binaries... The rest of a.out is also kind of weird; for example, there is support for loading text at an unaligned offset (by copying code into an anonymous mapping), but from a glance, it looks like the resulting text mapping wouldn't actually be executable? And there is support for loading files without mmap handler, except that an earlier security check prevents the use of files without mmap handler, unless you're on x86-64, where the copied code in ia32_aout.c is used that doesn't have that security check. ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-05 14:59 ` [PATCH] x86: Deprecate a.out support Borislav Petkov @ 2019-03-05 15:17 ` Richard Weinberger 2019-03-05 16:22 ` Linus Torvalds 1 sibling, 0 replies; 42+ messages in thread From: Richard Weinberger @ 2019-03-05 15:17 UTC (permalink / raw) To: Borislav Petkov Cc: Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Linus Torvalds, Anton Ivanov Am Dienstag, 5. März 2019, 15:59:52 CET schrieb Borislav Petkov: > + akpm and Linus. > > On Tue, Mar 05, 2019 at 01:43:47PM +0000, Alan Cox wrote: > > > It's been 25 years since Linux added support for ELF. Can we just > > > delete the a.out support entirely now? According to the Linux-ELF HOWTO, > > > support was added in 1.1.52 (August 1994). It's pretty much necromancy > > > at this point. > > > > In the unlikely event that someone actually has an a.out binary they > > can't live with they can also just write an a.out loader as an ELF > > program entirely in userspace. > > > > I'd vote for giving it the boot unless there are any architectures that > > kept using a.out far longer due to tool chain issues ? > > We can at least deprecate it on x86... > > --- > From: Borislav Petkov <bp@suse.de> > Date: Tue, 5 Mar 2019 15:47:51 +0100 > Subject: [PATCH] x86: Deprecate a.out support > > Linux supports ELF binaries for ~25 years now. a.out coredumping has > bitrotten quite significantly and would need some fixing to get it into > shape again but considering how even the toolchains cannot create a.out > executables in its default configuration, let's deprecate a.out support > and remove it a couple of releases later, instead. > > Signed-off-by: Borislav Petkov <bp@suse.de> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> > Cc: Jann Horn <jannh@google.com> > Cc: <linux-api@vger.kernel.org> > Cc: <linux-fsdevel@vger.kernel.org> > Cc: lkml <linux-kernel@vger.kernel.org> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Richard Weinberger <richard@nod.at> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: <x86@kernel.org> > --- > arch/x86/Kconfig | 2 +- > arch/x86/um/Kconfig | 1 - > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 68261430fe6e..ade12ec4224b 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -14,7 +14,6 @@ config X86_32 > select ARCH_WANT_IPC_PARSE_VERSION > select CLKSRC_I8253 > select CLONE_BACKWARDS > - select HAVE_AOUT > select HAVE_GENERIC_DMA_COHERENT > select MODULES_USE_ELF_REL > select OLD_SIGACTION > @@ -2843,6 +2842,7 @@ config IA32_EMULATION > config IA32_AOUT > tristate "IA32 a.out support" > depends on IA32_EMULATION > + depends on BROKEN > ---help--- > Support old a.out binaries in the 32bit emulation. > > diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig > index f518b4744ff8..494eeb51e4e1 100644 > --- a/arch/x86/um/Kconfig > +++ b/arch/x86/um/Kconfig > @@ -16,7 +16,6 @@ config 64BIT > > config X86_32 > def_bool !64BIT > - select HAVE_AOUT > select ARCH_WANT_IPC_PARSE_VERSION > select MODULES_USE_ELF_REL > select CLONE_BACKWARDS > For UML, Acked-by: Richard Weinberger <richard@nod.at> Thanks, //richard ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-10 21:37 ` Matt Turner @ 2019-03-10 22:40 ` Linus Torvalds 2019-03-10 23:19 ` Al Viro ` (3 more replies) 0 siblings, 4 replies; 42+ messages in thread From: Linus Torvalds @ 2019-03-10 22:40 UTC (permalink / raw) To: Matt Turner Cc: Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k [-- Attachment #1: Type: text/plain, Size: 741 bytes --] On Sun, Mar 10, 2019 at 2:37 PM Matt Turner <mattst88@gmail.com> wrote: > > I'm not aware of a reason to keep a.out support on alpha. Hmm. I was looking at removing a.out support entirely, but it's actually fairly incestuous on alpha. For example, arch/alpha/boot/tools/objstrip.c very much has some a.out support in it. Maybe it can just be removed entirely. There's also an a.out.h include in arch/alpha/kernel/binfmt_loader.c. Finally, note that CONFIG_OSF4_COMPAT also no longer makes sense without a.out support. So this attached patch does not compile on alpha, but it's been many many years since I had an alpha to test with, so I'm stuck. Matt, can you fill in the details and complete this patch? Linus [-- Attachment #2: patch.diff --] [-- Type: text/x-patch, Size: 23855 bytes --] arch/alpha/Kconfig | 1 - arch/alpha/kernel/osf_sys.c | 30 ---- arch/m68k/Kconfig | 1 - arch/x86/Kconfig | 7 - arch/x86/ia32/Makefile | 2 - arch/x86/ia32/ia32_aout.c | 330 ------------------------------------------ fs/Kconfig.binfmt | 33 ----- fs/Makefile | 1 - fs/binfmt_aout.c | 343 -------------------------------------------- include/linux/a.out.h | 18 --- 10 files changed, 766 deletions(-) diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index 584a6e114853..9b9770b45f36 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -10,7 +10,6 @@ config ALPHA select FORCE_PCI if !ALPHA_JENSEN select PCI_DOMAINS if PCI select PCI_SYSCALL if PCI - select HAVE_AOUT select HAVE_IDE select HAVE_OPROFILE select HAVE_PCSPKR_PLATFORM diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c index bf497b8b0ec6..09a0746c9681 100644 --- a/arch/alpha/kernel/osf_sys.c +++ b/arch/alpha/kernel/osf_sys.c @@ -1342,45 +1342,15 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, return addr; } -#ifdef CONFIG_OSF4_COMPAT -/* Clear top 32 bits of iov_len in the user's buffer for - compatibility with old versions of OSF/1 where iov_len - was defined as int. */ -static int -osf_fix_iov_len(const struct iovec __user *iov, unsigned long count) -{ - unsigned long i; - - for (i = 0 ; i < count ; i++) { - int __user *iov_len_high = (int __user *)&iov[i].iov_len + 1; - - if (put_user(0, iov_len_high)) - return -EFAULT; - } - return 0; -} -#endif - SYSCALL_DEFINE3(osf_readv, unsigned long, fd, const struct iovec __user *, vector, unsigned long, count) { -#ifdef CONFIG_OSF4_COMPAT - if (unlikely(personality(current->personality) == PER_OSF4)) - if (osf_fix_iov_len(vector, count)) - return -EFAULT; -#endif - return sys_readv(fd, vector, count); } SYSCALL_DEFINE3(osf_writev, unsigned long, fd, const struct iovec __user *, vector, unsigned long, count) { -#ifdef CONFIG_OSF4_COMPAT - if (unlikely(personality(current->personality) == PER_OSF4)) - if (osf_fix_iov_len(vector, count)) - return -EFAULT; -#endif return sys_writev(fd, vector, count); } diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index b54206408f91..65d263c60669 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -8,7 +8,6 @@ config M68K select ARCH_NO_COHERENT_DMA_MMAP if !MMU select ARCH_NO_PREEMPT if !COLDFIRE select HAVE_IDE - select HAVE_AOUT if MMU select HAVE_DEBUG_BUGVERBOSE select GENERIC_IRQ_SHOW select GENERIC_ATOMIC64 diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c1f9b3cf437c..4a9438e4fba6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2836,13 +2836,6 @@ config IA32_EMULATION 64-bit kernel. You should likely turn this on, unless you're 100% sure that you don't have any 32-bit programs left. -config IA32_AOUT - tristate "IA32 a.out support" - depends on IA32_EMULATION - depends on BROKEN - ---help--- - Support old a.out binaries in the 32bit emulation. - config X86_X32 bool "x32 ABI for 64-bit mode" depends on X86_64 diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile index cd4339bae066..b98fedaa7642 100644 --- a/arch/x86/ia32/Makefile +++ b/arch/x86/ia32/Makefile @@ -4,7 +4,5 @@ obj-$(CONFIG_IA32_EMULATION) := sys_ia32.o ia32_signal.o -obj-$(CONFIG_IA32_AOUT) += ia32_aout.o - audit-class-$(CONFIG_AUDIT) := audit.o obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y) diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c deleted file mode 100644 index 3c135084e1eb..000000000000 --- a/arch/x86/ia32/ia32_aout.c +++ /dev/null @@ -1,330 +0,0 @@ -/* - * a.out loader for x86-64 - * - * Copyright (C) 1991, 1992, 1996 Linus Torvalds - * Hacked together by Andi Kleen - */ - -#include <linux/module.h> - -#include <linux/time.h> -#include <linux/kernel.h> -#include <linux/mm.h> -#include <linux/mman.h> -#include <linux/a.out.h> -#include <linux/errno.h> -#include <linux/signal.h> -#include <linux/string.h> -#include <linux/fs.h> -#include <linux/file.h> -#include <linux/stat.h> -#include <linux/fcntl.h> -#include <linux/ptrace.h> -#include <linux/user.h> -#include <linux/binfmts.h> -#include <linux/personality.h> -#include <linux/init.h> -#include <linux/jiffies.h> -#include <linux/perf_event.h> -#include <linux/sched/task_stack.h> - -#include <linux/uaccess.h> -#include <asm/pgalloc.h> -#include <asm/cacheflush.h> -#include <asm/user32.h> -#include <asm/ia32.h> - -#undef WARN_OLD - -static int load_aout_binary(struct linux_binprm *); -static int load_aout_library(struct file *); - -static struct linux_binfmt aout_format = { - .module = THIS_MODULE, - .load_binary = load_aout_binary, - .load_shlib = load_aout_library, -}; - -static int set_brk(unsigned long start, unsigned long end) -{ - start = PAGE_ALIGN(start); - end = PAGE_ALIGN(end); - if (end <= start) - return 0; - return vm_brk(start, end - start); -} - - -/* - * create_aout_tables() parses the env- and arg-strings in new user - * memory and creates the pointer tables from them, and puts their - * addresses on the "stack", returning the new stack pointer value. - */ -static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm) -{ - u32 __user *argv, *envp, *sp; - int argc = bprm->argc, envc = bprm->envc; - - sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p); - sp -= envc+1; - envp = sp; - sp -= argc+1; - argv = sp; - put_user((unsigned long) envp, --sp); - put_user((unsigned long) argv, --sp); - put_user(argc, --sp); - current->mm->arg_start = (unsigned long) p; - while (argc-- > 0) { - char c; - - put_user((u32)(unsigned long)p, argv++); - do { - get_user(c, p++); - } while (c); - } - put_user(0, argv); - current->mm->arg_end = current->mm->env_start = (unsigned long) p; - while (envc-- > 0) { - char c; - - put_user((u32)(unsigned long)p, envp++); - do { - get_user(c, p++); - } while (c); - } - put_user(0, envp); - current->mm->env_end = (unsigned long) p; - return sp; -} - -/* - * These are the functions used to load a.out style executables and shared - * libraries. There is no binary dependent code anywhere else. - */ -static int load_aout_binary(struct linux_binprm *bprm) -{ - unsigned long error, fd_offset, rlim; - struct pt_regs *regs = current_pt_regs(); - struct exec ex; - int retval; - - ex = *((struct exec *) bprm->buf); /* exec-header */ - if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && - N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || - N_TRSIZE(ex) || N_DRSIZE(ex) || - i_size_read(file_inode(bprm->file)) < - ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { - return -ENOEXEC; - } - - fd_offset = N_TXTOFF(ex); - - /* Check initial limits. This avoids letting people circumvent - * size limits imposed on them by creating programs with large - * arrays in the data or bss. - */ - rlim = rlimit(RLIMIT_DATA); - if (rlim >= RLIM_INFINITY) - rlim = ~0; - if (ex.a_data + ex.a_bss > rlim) - return -ENOMEM; - - /* Flush all traces of the currently running executable */ - retval = flush_old_exec(bprm); - if (retval) - return retval; - - /* OK, This is the point of no return */ - set_personality(PER_LINUX); - set_personality_ia32(false); - - setup_new_exec(bprm); - - regs->cs = __USER32_CS; - regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = - regs->r13 = regs->r14 = regs->r15 = 0; - - current->mm->end_code = ex.a_text + - (current->mm->start_code = N_TXTADDR(ex)); - current->mm->end_data = ex.a_data + - (current->mm->start_data = N_DATADDR(ex)); - current->mm->brk = ex.a_bss + - (current->mm->start_brk = N_BSSADDR(ex)); - - retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT); - if (retval < 0) - return retval; - - install_exec_creds(bprm); - - if (N_MAGIC(ex) == OMAGIC) { - unsigned long text_addr, map_size; - - text_addr = N_TXTADDR(ex); - map_size = ex.a_text+ex.a_data; - - error = vm_brk(text_addr & PAGE_MASK, map_size); - - if (error) - return error; - - error = read_code(bprm->file, text_addr, 32, - ex.a_text + ex.a_data); - if ((signed long)error < 0) - return error; - } else { -#ifdef WARN_OLD - static unsigned long error_time, error_time2; - if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && - (N_MAGIC(ex) != NMAGIC) && - time_after(jiffies, error_time2 + 5*HZ)) { - printk(KERN_NOTICE "executable not page aligned

"); - error_time2 = jiffies; - } - - if ((fd_offset & ~PAGE_MASK) != 0 && - time_after(jiffies, error_time + 5*HZ)) { - printk(KERN_WARNING - "fd_offset is not page aligned. Please convert " - "program: %pD

", - bprm->file); - error_time = jiffies; - } -#endif - - if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) { - error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); - if (error) - return error; - - read_code(bprm->file, N_TXTADDR(ex), fd_offset, - ex.a_text+ex.a_data); - goto beyond_if; - } - - error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, - PROT_READ | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | - MAP_EXECUTABLE | MAP_32BIT, - fd_offset); - - if (error != N_TXTADDR(ex)) - return error; - - error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | - MAP_EXECUTABLE | MAP_32BIT, - fd_offset + ex.a_text); - if (error != N_DATADDR(ex)) - return error; - } - -beyond_if: - error = set_brk(current->mm->start_brk, current->mm->brk); - if (error) - return error; - - set_binfmt(&aout_format); - - current->mm->start_stack = - (unsigned long)create_aout_tables((char __user *)bprm->p, bprm); - /* start thread */ - loadsegment(fs, 0); - loadsegment(ds, __USER32_DS); - loadsegment(es, __USER32_DS); - load_gs_index(0); - (regs)->ip = ex.a_entry; - (regs)->sp = current->mm->start_stack; - (regs)->flags = 0x200; - (regs)->cs = __USER32_CS; - (regs)->ss = __USER32_DS; - regs->r8 = regs->r9 = regs->r10 = regs->r11 = - regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0; - set_fs(USER_DS); - return 0; -} - -static int load_aout_library(struct file *file) -{ - unsigned long bss, start_addr, len, error; - int retval; - struct exec ex; - loff_t pos = 0; - - retval = -ENOEXEC; - error = kernel_read(file, &ex, sizeof(ex), &pos); - if (error != sizeof(ex)) - goto out; - - /* We come in here for the regular a.out style of shared libraries */ - if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || - N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || - i_size_read(file_inode(file)) < - ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { - goto out; - } - - if (N_FLAGS(ex)) - goto out; - - /* For QMAGIC, the starting address is 0x20 into the page. We mask - this off to get the starting address for the page */ - - start_addr = ex.a_entry & 0xfffff000; - - if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { -#ifdef WARN_OLD - static unsigned long error_time; - if (time_after(jiffies, error_time + 5*HZ)) { - printk(KERN_WARNING - "N_TXTOFF is not page aligned. Please convert " - "library: %pD

", - file); - error_time = jiffies; - } -#endif - retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); - if (retval) - goto out; - - read_code(file, start_addr, N_TXTOFF(ex), - ex.a_text + ex.a_data); - retval = 0; - goto out; - } - /* Now use mmap to map the library into memory. */ - error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT, - N_TXTOFF(ex)); - retval = error; - if (error != start_addr) - goto out; - - len = PAGE_ALIGN(ex.a_text + ex.a_data); - bss = ex.a_text + ex.a_data + ex.a_bss; - if (bss > len) { - retval = vm_brk(start_addr + len, bss - len); - if (retval) - goto out; - } - retval = 0; -out: - return retval; -} - -static int __init init_aout_binfmt(void) -{ - register_binfmt(&aout_format); - return 0; -} - -static void __exit exit_aout_binfmt(void) -{ - unregister_binfmt(&aout_format); -} - -module_init(init_aout_binfmt); -module_exit(exit_aout_binfmt); -MODULE_LICENSE("GPL"); diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt index b795f8da81f3..b4dfd2a92d95 100644 --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -109,39 +109,6 @@ config BINFMT_SHARED_FLAT help Support FLAT shared libraries -config HAVE_AOUT - def_bool n - -config BINFMT_AOUT - tristate "Kernel support for a.out and ECOFF binaries" - depends on HAVE_AOUT - ---help--- - A.out (Assembler.OUTput) is a set of formats for libraries and - executables used in the earliest versions of UNIX. Linux used - the a.out formats QMAGIC and ZMAGIC until they were replaced - with the ELF format. - - The conversion to ELF started in 1995. This option is primarily - provided for historical interest and for the benefit of those - who need to run binaries from that era. - - Most people should answer N here. If you think you may have - occasional use for this format, enable module support above - and answer M here to compile this support as a module called - binfmt_aout. - - If any crucial components of your system (such as /sbin/init - or /lib/ld.so) are still in a.out format, you will have to - say Y here. - -config OSF4_COMPAT - bool "OSF/1 v4 readv/writev compatibility" - depends on ALPHA && BINFMT_AOUT - help - Say Y if you are using OSF/1 binaries (like Netscape and Acrobat) - with v4 shared libraries freely available from Compaq. If you're - going to use shared libraries from Tru64 version 5.0 or later, say N. - config BINFMT_EM86 tristate "Kernel support for Linux/Intel ELF binaries" depends on ALPHA diff --git a/fs/Makefile b/fs/Makefile index 7bff9abecfa4..0105e3496259 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -36,7 +36,6 @@ obj-$(CONFIG_FS_DAX) += dax.o obj-$(CONFIG_FS_ENCRYPTION) += crypto/ obj-$(CONFIG_FILE_LOCKING) += locks.o obj-$(CONFIG_COMPAT) += compat.o compat_ioctl.o -obj-$(CONFIG_BINFMT_AOUT) += binfmt_aout.o obj-$(CONFIG_BINFMT_EM86) += binfmt_em86.o obj-$(CONFIG_BINFMT_MISC) += binfmt_misc.o obj-$(CONFIG_BINFMT_SCRIPT) += binfmt_script.o diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c deleted file mode 100644 index 1fefd87eb4b4..000000000000 --- a/fs/binfmt_aout.c +++ /dev/null @@ -1,343 +0,0 @@ -/* - * linux/fs/binfmt_aout.c - * - * Copyright (C) 1991, 1992, 1996 Linus Torvalds - */ - -#include <linux/module.h> - -#include <linux/time.h> -#include <linux/kernel.h> -#include <linux/mm.h> -#include <linux/mman.h> -#include <linux/a.out.h> -#include <linux/errno.h> -#include <linux/signal.h> -#include <linux/string.h> -#include <linux/fs.h> -#include <linux/file.h> -#include <linux/stat.h> -#include <linux/fcntl.h> -#include <linux/ptrace.h> -#include <linux/user.h> -#include <linux/binfmts.h> -#include <linux/personality.h> -#include <linux/init.h> -#include <linux/coredump.h> -#include <linux/slab.h> -#include <linux/sched/task_stack.h> - -#include <linux/uaccess.h> -#include <asm/cacheflush.h> - -static int load_aout_binary(struct linux_binprm *); -static int load_aout_library(struct file*); - -static struct linux_binfmt aout_format = { - .module = THIS_MODULE, - .load_binary = load_aout_binary, - .load_shlib = load_aout_library, -}; - -#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE) - -static int set_brk(unsigned long start, unsigned long end) -{ - start = PAGE_ALIGN(start); - end = PAGE_ALIGN(end); - if (end > start) - return vm_brk(start, end - start); - return 0; -} - -/* - * create_aout_tables() parses the env- and arg-strings in new user - * memory and creates the pointer tables from them, and puts their - * addresses on the "stack", returning the new stack pointer value. - */ -static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) -{ - char __user * __user *argv; - char __user * __user *envp; - unsigned long __user *sp; - int argc = bprm->argc; - int envc = bprm->envc; - - sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); -#ifdef __alpha__ -/* whee.. test-programs are so much fun. */ - put_user(0, --sp); - put_user(0, --sp); - if (bprm->loader) { - put_user(0, --sp); - put_user(1003, --sp); - put_user(bprm->loader, --sp); - put_user(1002, --sp); - } - put_user(bprm->exec, --sp); - put_user(1001, --sp); -#endif - sp -= envc+1; - envp = (char __user * __user *) sp; - sp -= argc+1; - argv = (char __user * __user *) sp; -#ifndef __alpha__ - put_user((unsigned long) envp,--sp); - put_user((unsigned long) argv,--sp); -#endif - put_user(argc,--sp); - current->mm->arg_start = (unsigned long) p; - while (argc-->0) { - char c; - put_user(p,argv++); - do { - get_user(c,p++); - } while (c); - } - put_user(NULL,argv); - current->mm->arg_end = current->mm->env_start = (unsigned long) p; - while (envc-->0) { - char c; - put_user(p,envp++); - do { - get_user(c,p++); - } while (c); - } - put_user(NULL,envp); - current->mm->env_end = (unsigned long) p; - return sp; -} - -/* - * These are the functions used to load a.out style executables and shared - * libraries. There is no binary dependent code anywhere else. - */ - -static int load_aout_binary(struct linux_binprm * bprm) -{ - struct pt_regs *regs = current_pt_regs(); - struct exec ex; - unsigned long error; - unsigned long fd_offset; - unsigned long rlim; - int retval; - - ex = *((struct exec *) bprm->buf); /* exec-header */ - if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && - N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || - N_TRSIZE(ex) || N_DRSIZE(ex) || - i_size_read(file_inode(bprm->file)) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { - return -ENOEXEC; - } - - /* - * Requires a mmap handler. This prevents people from using a.out - * as part of an exploit attack against /proc-related vulnerabilities. - */ - if (!bprm->file->f_op->mmap) - return -ENOEXEC; - - fd_offset = N_TXTOFF(ex); - - /* Check initial limits. This avoids letting people circumvent - * size limits imposed on them by creating programs with large - * arrays in the data or bss. - */ - rlim = rlimit(RLIMIT_DATA); - if (rlim >= RLIM_INFINITY) - rlim = ~0; - if (ex.a_data + ex.a_bss > rlim) - return -ENOMEM; - - /* Flush all traces of the currently running executable */ - retval = flush_old_exec(bprm); - if (retval) - return retval; - - /* OK, This is the point of no return */ -#ifdef __alpha__ - SET_AOUT_PERSONALITY(bprm, ex); -#else - set_personality(PER_LINUX); -#endif - setup_new_exec(bprm); - - current->mm->end_code = ex.a_text + - (current->mm->start_code = N_TXTADDR(ex)); - current->mm->end_data = ex.a_data + - (current->mm->start_data = N_DATADDR(ex)); - current->mm->brk = ex.a_bss + - (current->mm->start_brk = N_BSSADDR(ex)); - - retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); - if (retval < 0) - return retval; - - install_exec_creds(bprm); - - if (N_MAGIC(ex) == OMAGIC) { - unsigned long text_addr, map_size; - loff_t pos; - - text_addr = N_TXTADDR(ex); - -#ifdef __alpha__ - pos = fd_offset; - map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; -#else - pos = 32; - map_size = ex.a_text+ex.a_data; -#endif - error = vm_brk(text_addr & PAGE_MASK, map_size); - if (error) - return error; - - error = read_code(bprm->file, text_addr, pos, - ex.a_text+ex.a_data); - if ((signed long)error < 0) - return error; - } else { - if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && - (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) - { - printk(KERN_NOTICE "executable not page aligned

"); - } - - if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) - { - printk(KERN_WARNING - "fd_offset is not page aligned. Please convert program: %pD

", - bprm->file); - } - - if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { - error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); - if (error) - return error; - - read_code(bprm->file, N_TXTADDR(ex), fd_offset, - ex.a_text + ex.a_data); - goto beyond_if; - } - - error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, - PROT_READ | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, - fd_offset); - - if (error != N_TXTADDR(ex)) - return error; - - error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, - fd_offset + ex.a_text); - if (error != N_DATADDR(ex)) - return error; - } -beyond_if: - set_binfmt(&aout_format); - - retval = set_brk(current->mm->start_brk, current->mm->brk); - if (retval < 0) - return retval; - - current->mm->start_stack = - (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); -#ifdef __alpha__ - regs->gp = ex.a_gpvalue; -#endif - finalize_exec(bprm); - start_thread(regs, ex.a_entry, current->mm->start_stack); - return 0; -} - -static int load_aout_library(struct file *file) -{ - struct inode * inode; - unsigned long bss, start_addr, len; - unsigned long error; - int retval; - struct exec ex; - loff_t pos = 0; - - inode = file_inode(file); - - retval = -ENOEXEC; - error = kernel_read(file, &ex, sizeof(ex), &pos); - if (error != sizeof(ex)) - goto out; - - /* We come in here for the regular a.out style of shared libraries */ - if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || - N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || - i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { - goto out; - } - - /* - * Requires a mmap handler. This prevents people from using a.out - * as part of an exploit attack against /proc-related vulnerabilities. - */ - if (!file->f_op->mmap) - goto out; - - if (N_FLAGS(ex)) - goto out; - - /* For QMAGIC, the starting address is 0x20 into the page. We mask - this off to get the starting address for the page */ - - start_addr = ex.a_entry & 0xfffff000; - - if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { - if (printk_ratelimit()) - { - printk(KERN_WARNING - "N_TXTOFF is not page aligned. Please convert library: %pD

", - file); - } - retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); - if (retval) - goto out; - - read_code(file, start_addr, N_TXTOFF(ex), - ex.a_text + ex.a_data); - retval = 0; - goto out; - } - /* Now use mmap to map the library into memory. */ - error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, - N_TXTOFF(ex)); - retval = error; - if (error != start_addr) - goto out; - - len = PAGE_ALIGN(ex.a_text + ex.a_data); - bss = ex.a_text + ex.a_data + ex.a_bss; - if (bss > len) { - retval = vm_brk(start_addr + len, bss - len); - if (retval) - goto out; - } - retval = 0; -out: - return retval; -} - -static int __init init_aout_binfmt(void) -{ - register_binfmt(&aout_format); - return 0; -} - -static void __exit exit_aout_binfmt(void) -{ - unregister_binfmt(&aout_format); -} - -core_initcall(init_aout_binfmt); -module_exit(exit_aout_binfmt); -MODULE_LICENSE("GPL"); diff --git a/include/linux/a.out.h b/include/linux/a.out.h deleted file mode 100644 index 600cf45645c6..000000000000 --- a/include/linux/a.out.h +++ /dev/null @@ -1,18 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef __A_OUT_GNU_H__ -#define __A_OUT_GNU_H__ - -#include <uapi/linux/a.out.h> - -#ifndef __ASSEMBLY__ -#ifdef linux -#include <asm/page.h> -#if defined(__i386__) || defined(__mc68000__) -#else -#ifndef SEGMENT_SIZE -#define SEGMENT_SIZE PAGE_SIZE -#endif -#endif -#endif -#endif /*__ASSEMBLY__ */ -#endif /* __A_OUT_GNU_H__ */ ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 16:45 ` Linus Torvalds @ 2019-03-11 18:08 ` Måns Rullgård 2019-03-11 19:03 ` Linus Torvalds 0 siblings, 1 reply; 42+ messages in thread From: Måns Rullgård @ 2019-03-11 18:08 UTC (permalink / raw) To: Linus Torvalds Cc: Matt Turner, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k Linus Torvalds <torvalds@linux-foundation.org> writes: > On Mon, Mar 11, 2019 at 9:26 AM Måns Rullgård <mans@mansr.com> wrote: >> >> Anyone running an Alpha machine likely also has some old OSF/1 binaries >> they may wish to use. It would be a shame to remove this feature, IMO. > > If that's the case then we'd have to keep a.out alive for alpha, since > that's the OSF/1 binary format (at least the only one we support - I'm > not sure if later versions of OSF/1 ended up getting ELF). The latest version I have is 5.1, and that uses ECOFF. > Which I guess we could do, but the question is whether people really > do have OSF/1 binaries. It was really useful early on as a source of > known-good binaries to test with, but I'm not convinced it's still in > use. > > It's not like there were OSF/1 binaries that we didn't havce access to > natively (well, there _were_ special ones that didn't have open source > versions, but most of them required more system-side support than > Linux ever implemented, afaik). I don't have any specific examples, but I can well imagine people keeping an Alpha machine for no other reason than the ability to run some (old) application only available (to them) for OSF/1. Running them on Linux rather than Tru64 brings the advantage of being a modern system in other regards. For anything open source, there's little reason to keep the Alpha at all. -- Måns Rullgård ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 19:47 ` Måns Rullgård 2019-03-11 20:50 ` Matt Turner @ 2019-03-11 21:34 ` Arnd Bergmann 2019-03-11 21:45 ` Linus Torvalds ` (2 more replies) 1 sibling, 3 replies; 42+ messages in thread From: Arnd Bergmann @ 2019-03-11 21:34 UTC (permalink / raw) To: Måns Rullgård Cc: Linus Torvalds, Matt Turner, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k On Mon, Mar 11, 2019 at 8:47 PM Måns Rullgård <mans@mansr.com> wrote: > Linus Torvalds <torvalds@linux-foundation.org> writes: > > On Mon, Mar 11, 2019 at 11:08 AM Måns Rullgård <mans@mansr.com> wrote: > >> > >> The latest version I have is 5.1, and that uses ECOFF. > > > > ECOFF _is_ a.out as far as Linux is concerned. > > > > So Linux basically treats ECOFF as "regular a.out with just some > > header extensions". > > > > We don't have any specific support for ECOFF. > > > > I _think_. Again, it's been years and years. > > Right, which is why killing a.out entirely would have the unfortunate > effect of also removing the OSF/1 compatibility on Alpha. > > If we are to support Alpha as an architecture at all, it makes sense to > support the things people actually use it for. > > Now, personally I can live without it. I just don't like to see > features removed without due consideration. The main historic use case I've heard of was running Netscape Navigator on Alpha Linux, before there was an open source version. Doing this today to connect to the open internet is probably a bit pointless, but there may be other use cases. Looking at the system call table in the kernel (arch/alpha/kernel/syscalls/syscall.tbl), we seem to support a specific subset that was required for a set of applications, and not much more. Old system calls (osf_old_open, osf_execve, osf_old_sigaction) are listed but not implemented, and the same is true for most of the later calls (osf_fuser, osf_sigsendset, osf_waitid, osf_signal, ...), just the ones in the middle are there. This would also indicate that it never really worked as a general-purpose emulation layer but was only there for a specific set of applications. Another data point I have is that osf1 emulation was broken between linux-4.13 and linux-4.16 without anyone noticing, see 47669fb6b595 ("alpha: osf_sys.c: fix put_tv32 regression"). Arnd ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 21:34 ` Arnd Bergmann 2019-03-11 21:45 ` Linus Torvalds @ 2019-03-11 22:06 ` Måns Rullgård 2019-03-11 22:11 ` Matt Turner 2 siblings, 0 replies; 42+ messages in thread From: Måns Rullgård @ 2019-03-11 22:06 UTC (permalink / raw) To: Arnd Bergmann Cc: Linus Torvalds, Matt Turner, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k Arnd Bergmann <arnd@arndb.de> writes: > On Mon, Mar 11, 2019 at 8:47 PM Måns Rullgård <mans@mansr.com> wrote: >> Linus Torvalds <torvalds@linux-foundation.org> writes: >> > On Mon, Mar 11, 2019 at 11:08 AM Måns Rullgård <mans@mansr.com> wrote: >> >> >> >> The latest version I have is 5.1, and that uses ECOFF. >> > >> > ECOFF _is_ a.out as far as Linux is concerned. >> > >> > So Linux basically treats ECOFF as "regular a.out with just some >> > header extensions". >> > >> > We don't have any specific support for ECOFF. >> > >> > I _think_. Again, it's been years and years. >> >> Right, which is why killing a.out entirely would have the unfortunate >> effect of also removing the OSF/1 compatibility on Alpha. >> >> If we are to support Alpha as an architecture at all, it makes sense to >> support the things people actually use it for. >> >> Now, personally I can live without it. I just don't like to see >> features removed without due consideration. > > The main historic use case I've heard of was running Netscape > Navigator on Alpha Linux, before there was an open source version. > Doing this today to connect to the open internet is probably > a bit pointless, but there may be other use cases. Once upon a time, I used it to run Matlab. > Looking at the system call table in the kernel > (arch/alpha/kernel/syscalls/syscall.tbl), we seem to support a > specific subset that was required for a set of applications, and > not much more. Old system calls (osf_old_open, osf_execve, > osf_old_sigaction) are listed but not implemented, and the same > is true for most of the later calls (osf_fuser, osf_sigsendset, > osf_waitid, osf_signal, ...), just the ones in the middle are there. > This would also indicate that it never really worked as a > general-purpose emulation layer but was only there for a specific > set of applications. It works for many applications, though I did have to add a few syscalls myself (yes, I sent patches). > Another data point I have is that osf1 emulation was broken > between linux-4.13 and linux-4.16 without anyone noticing, see > 47669fb6b595 ("alpha: osf_sys.c: fix put_tv32 regression"). That's interesting, but it doesn't mean nobody is using it. I tend to run the LTS branches and switch to a new one only once it seems to have settled a bit, so when 4.16 was released, I was probably still running 4.9. I don't think I'm the only one using this strategy. -- Måns Rullgård ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 21:34 ` Arnd Bergmann 2019-03-11 21:45 ` Linus Torvalds 2019-03-11 22:06 ` Måns Rullgård @ 2019-03-11 22:11 ` Matt Turner 2019-03-12 6:38 ` Michael Cree 2 siblings, 1 reply; 42+ messages in thread From: Matt Turner @ 2019-03-11 22:11 UTC (permalink / raw) To: Arnd Bergmann Cc: Måns Rullgård, Linus Torvalds, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k On Mon, Mar 11, 2019 at 2:34 PM Arnd Bergmann <arnd@arndb.de> wrote: > > On Mon, Mar 11, 2019 at 8:47 PM Måns Rullgård <mans@mansr.com> wrote: > > Linus Torvalds <torvalds@linux-foundation.org> writes: > > > On Mon, Mar 11, 2019 at 11:08 AM Måns Rullgård <mans@mansr.com> wrote: > > >> > > >> The latest version I have is 5.1, and that uses ECOFF. > > > > > > ECOFF _is_ a.out as far as Linux is concerned. > > > > > > So Linux basically treats ECOFF as "regular a.out with just some > > > header extensions". > > > > > > We don't have any specific support for ECOFF. > > > > > > I _think_. Again, it's been years and years. > > > > Right, which is why killing a.out entirely would have the unfortunate > > effect of also removing the OSF/1 compatibility on Alpha. > > > > If we are to support Alpha as an architecture at all, it makes sense to > > support the things people actually use it for. > > > > Now, personally I can live without it. I just don't like to see > > features removed without due consideration. > > The main historic use case I've heard of was running Netscape > Navigator on Alpha Linux, before there was an open source version. > Doing this today to connect to the open internet is probably > a bit pointless, but there may be other use cases. The best use case I know of is to run their C compiler. Måns sent patches in fact to make it work. There is a Linux version of the same compiler but I have a vague memory that it's broken in various ways that the Tru64 version is not. ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 21:45 ` Linus Torvalds @ 2019-03-11 22:12 ` Måns Rullgård 2019-03-12 8:44 ` Geert Uytterhoeven 1 sibling, 0 replies; 42+ messages in thread From: Måns Rullgård @ 2019-03-11 22:12 UTC (permalink / raw) To: Linus Torvalds Cc: Arnd Bergmann, Matt Turner, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k Linus Torvalds <torvalds@linux-foundation.org> writes: > On Mon, Mar 11, 2019 at 2:34 PM Arnd Bergmann <arnd@arndb.de> wrote: >> >> The main historic use case I've heard of was running Netscape >> Navigator on Alpha Linux, before there was an open source version. >> Doing this today to connect to the open internet is probably >> a bit pointless, but there may be other use cases. > > The _really_ main version was that I decided to make my life easier > for the initial alpha port by trying to run basic (tested) OSF/1 > binaries directly. > > Netscape may have been one of the binaries people actually ended up > using, but it's probably not a reason any more, since the internet has > moved past that anyway. > >> Looking at the system call table in the kernel >> (arch/alpha/kernel/syscalls/syscall.tbl), we seem to support a >> specific subset that was required for a set of applications, and >> not much more. > > Yeah, it never supported arbitrary binaries, particularly since > there's often lots of other issues too with running things like that > (ie filesystem layout etc). It worked for normal fairly well behaved > stuff, but wasn't ever a full OSF/1 emulation environment. > > I _suspect_ nobody actually runs any OSF/1 binaries any more, but it > would obviously be good to verify that. Your argument that timeval > handling was broken _may_ be an indication of that (or may just mean > very few apps care). Does it count if I fire up an Alpha and run a few OSF/1 binaries right now? :-) -- Måns Rullgård ^ permalink raw reply [flat|nested] 42+ messages in thread

* Re: [PATCH] x86: Deprecate a.out support 2019-03-11 22:11 ` Matt Turner @ 2019-03-12 6:38 ` Michael Cree 0 siblings, 0 replies; 42+ messages in thread From: Michael Cree @ 2019-03-12 6:38 UTC (permalink / raw) To: Matt Turner Cc: Arnd Bergmann, Måns Rullgård, Linus Torvalds, Borislav Petkov, Alan Cox, Matthew Wilcox, Jann Horn, Al Viro, Thomas Gleixner, kernel list, linux-fsdevel, the arch/x86 maintainers, Linux API, Andrew Morton, Richard Weinberger, Anton Ivanov, linux-alpha, linux-m68k On Mon, Mar 11, 2019 at 03:11:55PM -0700, Matt Turner wrote: > On Mon, Mar 11, 2019 at 2:34 PM Arnd Bergmann <arnd@arndb.de> wrote: > > On Mon, Mar 11, 2019 at 8:47 PM Måns Rullgård <mans@mansr.com> wrote: > > > Linus Torvalds <torvalds@linux-foundation.org> writes: > > > > On Mon, Mar 11, 2019 at 11:08 AM Måns Rullgård <mans@mansr.com> wrote: > > > > We don't have any specific support for ECOFF. > > > > > > > > I _think_. Again, it's been years and years. I agree. I personally have never run any OSF/1 executables on Linux Alpha and have no interest in doing so. > > The main historic use case I've heard of was running Netscape > > Navigator on Alpha Linux, before there was an open source version. > > Doing this today to connect to the open internet is probably > > a bit pointless, but there may be other use cases. > > The best use case I know of is to run their C compiler. Måns sent > patches in fact to make it work. > > There is a Linux version of the same compiler but I have a vague > memory that it's broken in various ways that the Tru64 version is > not. The last time I tried the Compaq C compiler for Alpha-Linux it still worked, well, that is, the compiler worked, but the library header files are broken and haven't worked with glibc for a long time. So it is only useful as a free-standing compiler. In the past it also produced better code than gcc, but gcc is now so vastly improved w.r.t. optimisation and compliance to more recent standards, that I would be surprised if there is any real use for the Compaq compiler. Cheers, Michael. ^ permalink raw reply [flat|nested] 42+ messages in thread

LKML Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \ linux-kernel@vger.kernel.org public-inbox-index lkml Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel AGPL code for this site: git clone https://public-inbox.org/public-inbox.git