Commit 046d662f authored by Alex Kelly's avatar Alex Kelly Committed by Linus Torvalds
Browse files

coredump: make core dump functionality optional 



Adds an expert Kconfig option, CONFIG_COREDUMP, which allows disabling of
core dump.  This saves approximately 2.6k in the compiled kernel, and
complements CONFIG_ELF_CORE, which now depends on it.

CONFIG_COREDUMP also disables coredump-related sysctls, except for
suid_dumpable and related functions, which are necessary for ptrace.

[akpm@linux-foundation.org: fix binfmt_aout.c build]
Signed-off-by: default avatarAlex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent db9aeca9

fs/Kconfig.binfmt

+8 −0
Original line number Diff line number Diff line
@@ -164,3 +164,11 @@ config BINFMT_MISC 
	  You may say M here for module support and later load the module when

	  you have use for it; the module is called binfmt_misc. If you

	  don't know what to answer at this point, say Y.



config COREDUMP

	bool "Enable core dump support" if EXPERT

	default y

	help

	  This option enables support for performing core dumps. You almost

	  certainly want to say Y here. Not necessary on systems that never

	  need debugging or only ever run flawless code.

fs/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \ 
		attr.o bad_inode.o file.o filesystems.o namespace.o \

		seq_file.o xattr.o libfs.o fs-writeback.o \

		pnode.o drop_caches.o splice.o sync.o utimes.o \

		stack.o fs_struct.o statfs.o coredump.o

		stack.o fs_struct.o statfs.o



ifeq ($(CONFIG_BLOCK),y)

obj-y +=	buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
@@ -48,6 +48,7 @@ obj-$(CONFIG_FS_MBCACHE) += mbcache.o 
obj-$(CONFIG_FS_POSIX_ACL)	+= posix_acl.o xattr_acl.o

obj-$(CONFIG_NFS_COMMON)	+= nfs_common/

obj-$(CONFIG_GENERIC_ACL)	+= generic_acl.o

obj-$(CONFIG_COREDUMP)		+= coredump.o



obj-$(CONFIG_FHANDLE)		+= fhandle.o

fs/binfmt_aout.c

+27 −25
Original line number Diff line number Diff line
@@ -32,31 +32,8 @@ 


static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);

static int load_aout_library(struct file*);

static int aout_core_dump(struct coredump_params *cprm);



static struct linux_binfmt aout_format = {

	.module		= THIS_MODULE,

	.load_binary	= load_aout_binary,

	.load_shlib	= load_aout_library,

	.core_dump	= aout_core_dump,

	.min_coredump	= PAGE_SIZE

};



#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) {

		unsigned long addr;

		addr = vm_brk(start, end - start);

		if (BAD_ADDR(addr))

			return addr;

	}

	return 0;

}



#ifdef CONFIG_COREDUMP

/*

 * Routine writes a core dump image in the current directory.

 * Currently only a stub-function.
@@ -66,7 +43,6 @@ static int set_brk(unsigned long start, unsigned long end) 
 * field, which also makes sure the core-dumps won't be recursive if the

 * dumping of the process results in another error..

 */



static int aout_core_dump(struct coredump_params *cprm)

{

	struct file *file = cprm->file;
@@ -135,6 +111,32 @@ end_coredump: 
	set_fs(fs);

	return has_dumped;

}

#else

#define aout_core_dump NULL

#endif



static struct linux_binfmt aout_format = {

	.module		= THIS_MODULE,

	.load_binary	= load_aout_binary,

	.load_shlib	= load_aout_library,

	.core_dump	= aout_core_dump,

	.min_coredump	= PAGE_SIZE

};



#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) {

		unsigned long addr;

		addr = vm_brk(start, end - start);

		if (BAD_ADDR(addr))

			return addr;

	}

	return 0;

}



/*

 * create_aout_tables() parses the env- and arg-strings in new user

include/linux/binfmts.h

+4 −0
Original line number Diff line number Diff line
@@ -132,7 +132,11 @@ extern int copy_strings_kernel(int argc, const char *const *argv, 
			       struct linux_binprm *bprm);

extern int prepare_bprm_creds(struct linux_binprm *bprm);

extern void install_exec_creds(struct linux_binprm *bprm);

#ifdef CONFIG_COREDUMP

extern void do_coredump(long signr, int exit_code, struct pt_regs *regs);

#else

static inline void do_coredump(long signr, int exit_code, struct pt_regs *regs) {}

#endif

extern void set_binfmt(struct linux_binfmt *new);

extern void free_bprm(struct linux_binprm *);

init/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -1199,6 +1199,7 @@ config BUG 
          Just say Y.



config ELF_CORE

	depends on COREDUMP

	default y

	bool "Enable ELF core dumps" if EXPERT

	help

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