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

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
...@@ -164,3 +164,11 @@ config BINFMT_MISC ...@@ -164,3 +164,11 @@ config BINFMT_MISC
You may say M here for module support and later load the module when 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 you have use for it; the module is called binfmt_misc. If you
don't know what to answer at this point, say Y. 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.
...@@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \ ...@@ -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 \ attr.o bad_inode.o file.o filesystems.o namespace.o \
seq_file.o xattr.o libfs.o fs-writeback.o \ seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o drop_caches.o splice.o sync.o utimes.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 ($(CONFIG_BLOCK),y) ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o obj-y += buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
...@@ -48,6 +48,7 @@ obj-$(CONFIG_FS_MBCACHE) += mbcache.o ...@@ -48,6 +48,7 @@ obj-$(CONFIG_FS_MBCACHE) += mbcache.o
obj-$(CONFIG_FS_POSIX_ACL) += posix_acl.o xattr_acl.o obj-$(CONFIG_FS_POSIX_ACL) += posix_acl.o xattr_acl.o
obj-$(CONFIG_NFS_COMMON) += nfs_common/ obj-$(CONFIG_NFS_COMMON) += nfs_common/
obj-$(CONFIG_GENERIC_ACL) += generic_acl.o obj-$(CONFIG_GENERIC_ACL) += generic_acl.o
obj-$(CONFIG_COREDUMP) += coredump.o
obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FHANDLE) += fhandle.o
......
...@@ -32,31 +32,8 @@ ...@@ -32,31 +32,8 @@
static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
static int load_aout_library(struct file*); 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. * Routine writes a core dump image in the current directory.
* Currently only a stub-function. * Currently only a stub-function.
...@@ -66,7 +43,6 @@ static int set_brk(unsigned long start, unsigned long end) ...@@ -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 * field, which also makes sure the core-dumps won't be recursive if the
* dumping of the process results in another error.. * dumping of the process results in another error..
*/ */
static int aout_core_dump(struct coredump_params *cprm) static int aout_core_dump(struct coredump_params *cprm)
{ {
struct file *file = cprm->file; struct file *file = cprm->file;
...@@ -135,6 +111,32 @@ static int aout_core_dump(struct coredump_params *cprm) ...@@ -135,6 +111,32 @@ static int aout_core_dump(struct coredump_params *cprm)
set_fs(fs); set_fs(fs);
return has_dumped; 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 * create_aout_tables() parses the env- and arg-strings in new user
......
...@@ -132,7 +132,11 @@ extern int copy_strings_kernel(int argc, const char *const *argv, ...@@ -132,7 +132,11 @@ extern int copy_strings_kernel(int argc, const char *const *argv,
struct linux_binprm *bprm); struct linux_binprm *bprm);
extern int prepare_bprm_creds(struct linux_binprm *bprm); extern int prepare_bprm_creds(struct linux_binprm *bprm);
extern void install_exec_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); 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 set_binfmt(struct linux_binfmt *new);
extern void free_bprm(struct linux_binprm *); extern void free_bprm(struct linux_binprm *);
......
...@@ -1199,6 +1199,7 @@ config BUG ...@@ -1199,6 +1199,7 @@ config BUG
Just say Y. Just say Y.
config ELF_CORE config ELF_CORE
depends on COREDUMP
default y default y
bool "Enable ELF core dumps" if EXPERT bool "Enable ELF core dumps" if EXPERT
help help
......
...@@ -97,10 +97,12 @@ ...@@ -97,10 +97,12 @@
extern int sysctl_overcommit_memory; extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio; extern int sysctl_overcommit_ratio;
extern int max_threads; extern int max_threads;
extern int core_uses_pid;
extern int suid_dumpable; extern int suid_dumpable;
#ifdef CONFIG_COREDUMP
extern int core_uses_pid;
extern char core_pattern[]; extern char core_pattern[];
extern unsigned int core_pipe_limit; extern unsigned int core_pipe_limit;
#endif
extern int pid_max; extern int pid_max;
extern int min_free_kbytes; extern int min_free_kbytes;
extern int pid_max_min, pid_max_max; extern int pid_max_min, pid_max_max;
...@@ -177,8 +179,10 @@ static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write, ...@@ -177,8 +179,10 @@ static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos); void __user *buffer, size_t *lenp, loff_t *ppos);
#ifdef CONFIG_COREDUMP
static int proc_dostring_coredump(struct ctl_table *table, int write, static int proc_dostring_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos); void __user *buffer, size_t *lenp, loff_t *ppos);
#endif
#ifdef CONFIG_MAGIC_SYSRQ #ifdef CONFIG_MAGIC_SYSRQ
/* Note: sysrq code uses it's own private copy */ /* Note: sysrq code uses it's own private copy */
...@@ -404,6 +408,7 @@ static struct ctl_table kern_table[] = { ...@@ -404,6 +408,7 @@ static struct ctl_table kern_table[] = {
.mode = 0644, .mode = 0644,
.proc_handler = proc_dointvec, .proc_handler = proc_dointvec,
}, },
#ifdef CONFIG_COREDUMP
{ {
.procname = "core_uses_pid", .procname = "core_uses_pid",
.data = &core_uses_pid, .data = &core_uses_pid,
...@@ -425,6 +430,7 @@ static struct ctl_table kern_table[] = { ...@@ -425,6 +430,7 @@ static struct ctl_table kern_table[] = {
.mode = 0644, .mode = 0644,
.proc_handler = proc_dointvec, .proc_handler = proc_dointvec,
}, },
#endif
#ifdef CONFIG_PROC_SYSCTL #ifdef CONFIG_PROC_SYSCTL
{ {
.procname = "tainted", .procname = "tainted",
...@@ -2036,12 +2042,14 @@ int proc_dointvec_minmax(struct ctl_table *table, int write, ...@@ -2036,12 +2042,14 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
static void validate_coredump_safety(void) static void validate_coredump_safety(void)
{ {
#ifdef CONFIG_COREDUMP
if (suid_dumpable == SUID_DUMPABLE_SAFE && if (suid_dumpable == SUID_DUMPABLE_SAFE &&
core_pattern[0] != '/' && core_pattern[0] != '|') { core_pattern[0] != '/' && core_pattern[0] != '|') {
printk(KERN_WARNING "Unsafe core_pattern used with "\ printk(KERN_WARNING "Unsafe core_pattern used with "\
"suid_dumpable=2. Pipe handler or fully qualified "\ "suid_dumpable=2. Pipe handler or fully qualified "\
"core dump path required.\n"); "core dump path required.\n");
} }
#endif
} }
static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
...@@ -2053,6 +2061,7 @@ static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, ...@@ -2053,6 +2061,7 @@ static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
return error; return error;
} }
#ifdef CONFIG_COREDUMP
static int proc_dostring_coredump(struct ctl_table *table, int write, static int proc_dostring_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos) void __user *buffer, size_t *lenp, loff_t *ppos)
{ {
...@@ -2061,6 +2070,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write, ...@@ -2061,6 +2070,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write,
validate_coredump_safety(); validate_coredump_safety();
return error; return error;
} }
#endif
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write, static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
void __user *buffer, void __user *buffer,
......
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