user/sven/linux.git/include/linux/binfmts.h, branch v3.3.5

exec: fix use-after-free bug in setup_new_exec()

2012-02-06T23:15:20Z

Setting the task name is done within setup_new_exec() by accessing bprm->filename. However this happens after flush_old_exec(). This may result in a use after free bug, flush_old_exec() may "complete" vfork_done, which will wake up the parent which in turn may free the passed in filename. To fix this add a new tcomm field in struct linux_binprm which contains the now early generated task name until it is used. Fixes this bug on s390: Unable to handle kernel pointer dereference at virtual kernel address 0000000039768000 Process kworker/u:3 (pid: 245, task: 000000003a3dc840, ksp: 0000000039453818) Krnl PSW : 0704000180000000 0000000000282e94 (setup_new_exec+0xa0/0x374) Call Trace: ([<0000000000282e2c>] setup_new_exec+0x38/0x374) [<00000000002dd12e>] load_elf_binary+0x402/0x1bf4 [<0000000000280a42>] search_binary_handler+0x38e/0x5bc [<0000000000282b6c>] do_execve_common+0x410/0x514 [<0000000000282cb6>] do_execve+0x46/0x58 [<00000000005bce58>] kernel_execve+0x28/0x70 [<000000000014ba2e>] ____call_usermodehelper+0x102/0x140 [<00000000005bc8da>] kernel_thread_starter+0x6/0xc [<00000000005bc8d4>] kernel_thread_starter+0x0/0xc Last Breaking-Event-Address: [<00000000002830f0>] setup_new_exec+0x2fc/0x374 Kernel panic - not syncing: Fatal exception: panic_on_oops Reported-by: Sebastian Ott Signed-off-by: Heiko Carstens Signed-off-by: Linus Torvalds

consolidate BINPRM_FLAGS_ENFORCE_NONDUMP handling

2011-07-20T05:43:10Z

new helper: would_dump(bprm, file). Checks if we are allowed to read the file and if we are not - sets ENFORCE_NODUMP. Exported, used in places that previously open-coded the same logics. Signed-off-by: Al Viro

exec: unify do_execve/compat_do_execve code

2011-04-09T13:53:56Z

Add the appropriate members into struct user_arg_ptr and teach get_user_arg_ptr() to handle is_compat = T case correctly. This allows us to remove the compat_do_execve() code from fs/compat.c and reimplement compat_do_execve() as the trivial wrapper on top of do_execve_common(is_compat => true). In fact, this fixes another (minor) bug. "compat_uptr_t str" can overflow after "str += len" in compat_copy_strings() if a 64bit application execs via sys32_execve(). Unexport acct_arg_size() and get_arg_page(), fs/compat.c doesn't need them any longer. Signed-off-by: Oleg Nesterov Reviewed-by: KOSAKI Motohiro Tested-by: KOSAKI Motohiro

binfmt_elf: cleanups

2011-01-13T16:03:12Z

This cleans up a few bits in binfmt_elf.c and binfmts.h: - the hasvdso field in struct linux_binfmt is unused, so remove it and the only initialization of it - the elf_map CPP symbol is not defined anywhere in the kernel, so remove an unnecessary #ifndef elf_map - reduce excessive indentation in elf_format's initializer - add missing spaces, remove extraneous spaces No functional changes, but tested on x86 (32 and 64 bit), powerpc (32 and 64 bit), sparc64, arm, and alpha. Signed-off-by: Mikael Pettersson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

exec: copy-and-paste the fixes into compat_do_execve() paths

2010-12-01T01:56:38Z

Note: this patch targets 2.6.37 and tries to be as simple as possible. That is why it adds more copy-and-paste horror into fs/compat.c and uglifies fs/exec.c, this will be cleanuped later. compat_copy_strings() plays with bprm->vma/mm directly and thus has two problems: it lacks the RLIMIT_STACK check and argv/envp memory is not visible to oom killer. Export acct_arg_size() and get_arg_page(), change compat_copy_strings() to use get_arg_page(), change compat_do_execve() to do acct_arg_size(0) as do_execve() does. Add the fatal_signal_pending/cond_resched checks into compat_count() and compat_copy_strings(), this matches the code in fs/exec.c and certainly makes sense. Signed-off-by: Oleg Nesterov Cc: KOSAKI Motohiro Cc: stable@kernel.org Signed-off-by: Linus Torvalds

exec: make argv/envp memory visible to oom-killer

2010-12-01T01:56:37Z

Brad Spengler published a local memory-allocation DoS that evades the OOM-killer (though not the virtual memory RLIMIT): http://www.grsecurity.net/~spender/64bit_dos.c execve()->copy_strings() can allocate a lot of memory, but this is not visible to oom-killer, nobody can see the nascent bprm->mm and take it into account. With this patch get_arg_page() increments current's MM_ANONPAGES counter every time we allocate the new page for argv/envp. When do_execve() succeds or fails, we change this counter back. Technically this is not 100% correct, we can't know if the new page is swapped out and turn MM_ANONPAGES into MM_SWAPENTS, but I don't think this really matters and everything becomes correct once exec changes ->mm or fails. Reported-by: Brad Spengler Reviewed-and-discussed-by: KOSAKI Motohiro Signed-off-by: Oleg Nesterov Cc: stable@kernel.org Signed-off-by: Linus Torvalds

Make do_execve() take a const filename pointer

2010-08-18T01:07:43Z

Make do_execve() take a const filename pointer so that kernel_execve() compiles correctly on ARM: arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type This also requires the argv and envp arguments to be consted twice, once for the pointer array and once for the strings the array points to. This is because do_execve() passes a pointer to the filename (now const) to copy_strings_kernel(). A simpler alternative would be to cast the filename pointer in do_execve() when it's passed to copy_strings_kernel(). do_execve() may not change any of the strings it is passed as part of the argv or envp lists as they are some of them in .rodata, so marking these strings as const should be fine. Further kernel_execve() and sys_execve() need to be changed to match. This has been test built on x86_64, frv, arm and mips. Signed-off-by: David Howells Tested-by: Ralf Baechle Acked-by: Russell King Signed-off-by: Linus Torvalds

coredump: pass mm->flags as a coredump parameter for consistency

2010-03-06T19:26:46Z

Pass mm->flags as a coredump parameter for consistency. --- 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1) 1788 up_write(&mm->mmap_sem); 1789 put_cred(cred); 1790 goto fail; 1791 } 1792 [...] 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2) 1799 flag = O_EXCL; /* Stop rewrite attacks */ 1800 cred->fsuid = 0; /* Dump root private */ 1801 } --- Since dumpable bits are not protected by lock, there is a chance to change these bits between (1) and (2). To solve this issue, this patch copies mm->flags to coredump_params.mm_flags at the beginning of do_coredump() and uses it instead of get_dumpable() while dumping core. This copy is also passed to binfmt->core_dump, since elf*_core_dump() uses dump_filter bits in mm->flags. [akpm@linux-foundation.org: fix merge] Signed-off-by: Masami Hiramatsu Acked-by: Roland McGrath Cc: Hidehiro Kawai Cc: Oleg Nesterov Cc: Ingo Molnar Reviewed-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Split 'flush_old_exec' into two functions

2010-01-29T16:22:01Z

'flush_old_exec()' is the point of no return when doing an execve(), and it is pretty badly misnamed. It doesn't just flush the old executable environment, it also starts up the new one. Which is very inconvenient for things like setting up the new personality, because we want the new personality to affect the starting of the new environment, but at the same time we do _not_ want the new personality to take effect if flushing the old one fails. As a result, the x86-64 '32-bit' personality is actually done using this insane "I'm going to change the ABI, but I haven't done it yet" bit (TIF_ABI_PENDING), with SET_PERSONALITY() not actually setting the personality, but just the "pending" bit, so that "flush_thread()" can do the actual personality magic. This patch in no way changes any of that insanity, but it does split the 'flush_old_exec()' function up into a preparatory part that can fail (still called flush_old_exec()), and a new part that will actually set up the new exec environment (setup_new_exec()). All callers are changed to trivially comply with the new world order. Signed-off-by: H. Peter Anvin Cc: stable@kernel.org Signed-off-by: Linus Torvalds

mm: introduce coredump parameter structure

2009-12-17T23:45:31Z

Introduce coredump parameter data structure (struct coredump_params) to simplify binfmt->core_dump() arguments. Signed-off-by: Masami Hiramatsu Suggested-by: Ingo Molnar Cc: Hidehiro Kawai Cc: Oleg Nesterov Cc: Roland McGrath Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds