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Diffstat (limited to 'fs/coredump.c')
-rw-r--r--fs/coredump.c290
1 files changed, 170 insertions, 120 deletions
diff --git a/fs/coredump.c b/fs/coredump.c
index 177493272a6..a93f7e6ea4c 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -40,74 +40,88 @@
#include <trace/events/task.h>
#include "internal.h"
-#include "coredump.h"
#include <trace/events/sched.h>
int core_uses_pid;
-char core_pattern[CORENAME_MAX_SIZE] = "core";
unsigned int core_pipe_limit;
+char core_pattern[CORENAME_MAX_SIZE] = "core";
+static int core_name_size = CORENAME_MAX_SIZE;
struct core_name {
char *corename;
int used, size;
};
-static atomic_t call_count = ATOMIC_INIT(1);
/* The maximal length of core_pattern is also specified in sysctl.c */
-static int expand_corename(struct core_name *cn)
+static int expand_corename(struct core_name *cn, int size)
{
- char *old_corename = cn->corename;
-
- cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
- cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
+ char *corename = krealloc(cn->corename, size, GFP_KERNEL);
- if (!cn->corename) {
- kfree(old_corename);
+ if (!corename)
return -ENOMEM;
- }
+ if (size > core_name_size) /* racy but harmless */
+ core_name_size = size;
+
+ cn->size = ksize(corename);
+ cn->corename = corename;
return 0;
}
+static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
+{
+ int free, need;
+ va_list arg_copy;
+
+again:
+ free = cn->size - cn->used;
+
+ va_copy(arg_copy, arg);
+ need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
+ va_end(arg_copy);
+
+ if (need < free) {
+ cn->used += need;
+ return 0;
+ }
+
+ if (!expand_corename(cn, cn->size + need - free + 1))
+ goto again;
+
+ return -ENOMEM;
+}
+
static int cn_printf(struct core_name *cn, const char *fmt, ...)
{
- char *cur;
- int need;
- int ret;
va_list arg;
+ int ret;
va_start(arg, fmt);
- need = vsnprintf(NULL, 0, fmt, arg);
+ ret = cn_vprintf(cn, fmt, arg);
va_end(arg);
- if (likely(need < cn->size - cn->used - 1))
- goto out_printf;
+ return ret;
+}
- ret = expand_corename(cn);
- if (ret)
- goto expand_fail;
+static int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
+{
+ int cur = cn->used;
+ va_list arg;
+ int ret;
-out_printf:
- cur = cn->corename + cn->used;
va_start(arg, fmt);
- vsnprintf(cur, need + 1, fmt, arg);
+ ret = cn_vprintf(cn, fmt, arg);
va_end(arg);
- cn->used += need;
- return 0;
-expand_fail:
+ for (; cur < cn->used; ++cur) {
+ if (cn->corename[cur] == '/')
+ cn->corename[cur] = '!';
+ }
return ret;
}
-static void cn_escape(char *str)
-{
- for (; *str; str++)
- if (*str == '/')
- *str = '!';
-}
-
static int cn_print_exe_file(struct core_name *cn)
{
struct file *exe_file;
@@ -115,12 +129,8 @@ static int cn_print_exe_file(struct core_name *cn)
int ret;
exe_file = get_mm_exe_file(current->mm);
- if (!exe_file) {
- char *commstart = cn->corename + cn->used;
- ret = cn_printf(cn, "%s (path unknown)", current->comm);
- cn_escape(commstart);
- return ret;
- }
+ if (!exe_file)
+ return cn_esc_printf(cn, "%s (path unknown)", current->comm);
pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
if (!pathbuf) {
@@ -134,9 +144,7 @@ static int cn_print_exe_file(struct core_name *cn)
goto free_buf;
}
- cn_escape(path);
-
- ret = cn_printf(cn, "%s", path);
+ ret = cn_esc_printf(cn, "%s", path);
free_buf:
kfree(pathbuf);
@@ -157,19 +165,19 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
int pid_in_pattern = 0;
int err = 0;
- cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
- cn->corename = kmalloc(cn->size, GFP_KERNEL);
cn->used = 0;
-
- if (!cn->corename)
+ cn->corename = NULL;
+ if (expand_corename(cn, core_name_size))
return -ENOMEM;
+ cn->corename[0] = '\0';
+
+ if (ispipe)
+ ++pat_ptr;
/* Repeat as long as we have more pattern to process and more output
space */
while (*pat_ptr) {
if (*pat_ptr != '%') {
- if (*pat_ptr == 0)
- goto out;
err = cn_printf(cn, "%c", *pat_ptr++);
} else {
switch (*++pat_ptr) {
@@ -186,6 +194,11 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
err = cn_printf(cn, "%d",
task_tgid_vnr(current));
break;
+ /* global pid */
+ case 'P':
+ err = cn_printf(cn, "%d",
+ task_tgid_nr(current));
+ break;
/* uid */
case 'u':
err = cn_printf(cn, "%d", cred->uid);
@@ -210,22 +223,16 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
break;
}
/* hostname */
- case 'h': {
- char *namestart = cn->corename + cn->used;
+ case 'h':
down_read(&uts_sem);
- err = cn_printf(cn, "%s",
+ err = cn_esc_printf(cn, "%s",
utsname()->nodename);
up_read(&uts_sem);
- cn_escape(namestart);
break;
- }
/* executable */
- case 'e': {
- char *commstart = cn->corename + cn->used;
- err = cn_printf(cn, "%s", current->comm);
- cn_escape(commstart);
+ case 'e':
+ err = cn_esc_printf(cn, "%s", current->comm);
break;
- }
case 'E':
err = cn_print_exe_file(cn);
break;
@@ -244,6 +251,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
return err;
}
+out:
/* Backward compatibility with core_uses_pid:
*
* If core_pattern does not include a %p (as is the default)
@@ -254,7 +262,6 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
if (err)
return err;
}
-out:
return ispipe;
}
@@ -263,7 +270,6 @@ static int zap_process(struct task_struct *start, int exit_code)
struct task_struct *t;
int nr = 0;
- start->signal->flags = SIGNAL_GROUP_EXIT;
start->signal->group_exit_code = exit_code;
start->signal->group_stop_count = 0;
@@ -280,8 +286,8 @@ static int zap_process(struct task_struct *start, int exit_code)
return nr;
}
-static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
- struct core_state *core_state, int exit_code)
+static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
+ struct core_state *core_state, int exit_code)
{
struct task_struct *g, *p;
unsigned long flags;
@@ -291,11 +297,16 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
if (!signal_group_exit(tsk->signal)) {
mm->core_state = core_state;
nr = zap_process(tsk, exit_code);
+ tsk->signal->group_exit_task = tsk;
+ /* ignore all signals except SIGKILL, see prepare_signal() */
+ tsk->signal->flags = SIGNAL_GROUP_COREDUMP;
+ clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
}
spin_unlock_irq(&tsk->sighand->siglock);
if (unlikely(nr < 0))
return nr;
+ tsk->flags |= PF_DUMPCORE;
if (atomic_read(&mm->mm_users) == nr + 1)
goto done;
/*
@@ -340,6 +351,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
if (unlikely(p->mm == mm)) {
lock_task_sighand(p, &flags);
nr += zap_process(p, exit_code);
+ p->signal->flags = SIGNAL_GROUP_EXIT;
unlock_task_sighand(p, &flags);
}
break;
@@ -386,11 +398,18 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
return core_waiters;
}
-static void coredump_finish(struct mm_struct *mm)
+static void coredump_finish(struct mm_struct *mm, bool core_dumped)
{
struct core_thread *curr, *next;
struct task_struct *task;
+ spin_lock_irq(&current->sighand->siglock);
+ if (core_dumped && !__fatal_signal_pending(current))
+ current->signal->group_exit_code |= 0x80;
+ current->signal->group_exit_task = NULL;
+ current->signal->flags = SIGNAL_GROUP_EXIT;
+ spin_unlock_irq(&current->sighand->siglock);
+
next = mm->core_state->dumper.next;
while ((curr = next) != NULL) {
next = curr->next;
@@ -407,26 +426,38 @@ static void coredump_finish(struct mm_struct *mm)
mm->core_state = NULL;
}
-static void wait_for_dump_helpers(struct file *file)
+static bool dump_interrupted(void)
{
- struct pipe_inode_info *pipe;
+ /*
+ * SIGKILL or freezing() interrupt the coredumping. Perhaps we
+ * can do try_to_freeze() and check __fatal_signal_pending(),
+ * but then we need to teach dump_write() to restart and clear
+ * TIF_SIGPENDING.
+ */
+ return signal_pending(current);
+}
- pipe = file->f_path.dentry->d_inode->i_pipe;
+static void wait_for_dump_helpers(struct file *file)
+{
+ struct pipe_inode_info *pipe = file->private_data;
pipe_lock(pipe);
pipe->readers++;
pipe->writers--;
+ wake_up_interruptible_sync(&pipe->wait);
+ kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+ pipe_unlock(pipe);
- while ((pipe->readers > 1) && (!signal_pending(current))) {
- wake_up_interruptible_sync(&pipe->wait);
- kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
- pipe_wait(pipe);
- }
+ /*
+ * We actually want wait_event_freezable() but then we need
+ * to clear TIF_SIGPENDING and improve dump_interrupted().
+ */
+ wait_event_interruptible(pipe->wait, pipe->readers == 1);
+ pipe_lock(pipe);
pipe->readers--;
pipe->writers++;
pipe_unlock(pipe);
-
}
/*
@@ -458,7 +489,7 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
return err;
}
-void do_coredump(siginfo_t *siginfo)
+void do_coredump(const siginfo_t *siginfo)
{
struct core_state core_state;
struct core_name cn;
@@ -471,6 +502,7 @@ void do_coredump(siginfo_t *siginfo)
int ispipe;
struct files_struct *displaced;
bool need_nonrelative = false;
+ bool core_dumped = false;
static atomic_t core_dump_count = ATOMIC_INIT(0);
struct coredump_params cprm = {
.siginfo = siginfo,
@@ -501,7 +533,7 @@ void do_coredump(siginfo_t *siginfo)
* so we dump it as root in mode 2, and only into a controlled
* environment (pipe handler or fully qualified path).
*/
- if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) {
+ if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) {
/* Setuid core dump mode */
flag = O_EXCL; /* Stop rewrite attacks */
cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */
@@ -514,22 +546,17 @@ void do_coredump(siginfo_t *siginfo)
old_cred = override_creds(cred);
- /*
- * Clear any false indication of pending signals that might
- * be seen by the filesystem code called to write the core file.
- */
- clear_thread_flag(TIF_SIGPENDING);
-
ispipe = format_corename(&cn, &cprm);
- if (ispipe) {
+ if (ispipe) {
int dump_count;
char **helper_argv;
+ struct subprocess_info *sub_info;
if (ispipe < 0) {
printk(KERN_WARNING "format_corename failed\n");
printk(KERN_WARNING "Aborting core\n");
- goto fail_corename;
+ goto fail_unlock;
}
if (cprm.limit == 1) {
@@ -564,22 +591,27 @@ void do_coredump(siginfo_t *siginfo)
goto fail_dropcount;
}
- helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
+ helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
if (!helper_argv) {
printk(KERN_WARNING "%s failed to allocate memory\n",
__func__);
goto fail_dropcount;
}
- retval = call_usermodehelper_fns(helper_argv[0], helper_argv,
- NULL, UMH_WAIT_EXEC, umh_pipe_setup,
- NULL, &cprm);
+ retval = -ENOMEM;
+ sub_info = call_usermodehelper_setup(helper_argv[0],
+ helper_argv, NULL, GFP_KERNEL,
+ umh_pipe_setup, NULL, &cprm);
+ if (sub_info)
+ retval = call_usermodehelper_exec(sub_info,
+ UMH_WAIT_EXEC);
+
argv_free(helper_argv);
if (retval) {
- printk(KERN_INFO "Core dump to %s pipe failed\n",
+ printk(KERN_INFO "Core dump to |%s pipe failed\n",
cn.corename);
goto close_fail;
- }
+ }
} else {
struct inode *inode;
@@ -600,7 +632,7 @@ void do_coredump(siginfo_t *siginfo)
if (IS_ERR(cprm.file))
goto fail_unlock;
- inode = cprm.file->f_path.dentry->d_inode;
+ inode = file_inode(cprm.file);
if (inode->i_nlink > 1)
goto close_fail;
if (d_unhashed(cprm.file->f_path.dentry))
@@ -617,7 +649,7 @@ void do_coredump(siginfo_t *siginfo)
*/
if (!uid_eq(inode->i_uid, current_fsuid()))
goto close_fail;
- if (!cprm.file->f_op || !cprm.file->f_op->write)
+ if (!cprm.file->f_op->write)
goto close_fail;
if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
goto close_fail;
@@ -629,10 +661,11 @@ void do_coredump(siginfo_t *siginfo)
goto close_fail;
if (displaced)
put_files_struct(displaced);
- retval = binfmt->core_dump(&cprm);
- if (retval)
- current->signal->group_exit_code |= 0x80;
-
+ if (!dump_interrupted()) {
+ file_start_write(cprm.file);
+ core_dumped = binfmt->core_dump(&cprm);
+ file_end_write(cprm.file);
+ }
if (ispipe && core_pipe_limit)
wait_for_dump_helpers(cprm.file);
close_fail:
@@ -643,8 +676,7 @@ fail_dropcount:
atomic_dec(&core_dump_count);
fail_unlock:
kfree(cn.corename);
-fail_corename:
- coredump_finish(mm);
+ coredump_finish(mm, core_dumped);
revert_creds(old_cred);
fail_creds:
put_cred(cred);
@@ -657,37 +689,55 @@ fail:
* do on a core-file: use only these functions to write out all the
* necessary info.
*/
-int dump_write(struct file *file, const void *addr, int nr)
+int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
{
- return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+ struct file *file = cprm->file;
+ loff_t pos = file->f_pos;
+ ssize_t n;
+ if (cprm->written + nr > cprm->limit)
+ return 0;
+ while (nr) {
+ if (dump_interrupted())
+ return 0;
+ n = __kernel_write(file, addr, nr, &pos);
+ if (n <= 0)
+ return 0;
+ file->f_pos = pos;
+ cprm->written += n;
+ nr -= n;
+ }
+ return 1;
}
-EXPORT_SYMBOL(dump_write);
+EXPORT_SYMBOL(dump_emit);
-int dump_seek(struct file *file, loff_t off)
+int dump_skip(struct coredump_params *cprm, size_t nr)
{
- int ret = 1;
-
+ static char zeroes[PAGE_SIZE];
+ struct file *file = cprm->file;
if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
- if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
+ if (cprm->written + nr > cprm->limit)
return 0;
- } else {
- char *buf = (char *)get_zeroed_page(GFP_KERNEL);
-
- if (!buf)
+ if (dump_interrupted() ||
+ file->f_op->llseek(file, nr, SEEK_CUR) < 0)
return 0;
- while (off > 0) {
- unsigned long n = off;
-
- if (n > PAGE_SIZE)
- n = PAGE_SIZE;
- if (!dump_write(file, buf, n)) {
- ret = 0;
- break;
- }
- off -= n;
+ cprm->written += nr;
+ return 1;
+ } else {
+ while (nr > PAGE_SIZE) {
+ if (!dump_emit(cprm, zeroes, PAGE_SIZE))
+ return 0;
+ nr -= PAGE_SIZE;
}
- free_page((unsigned long)buf);
+ return dump_emit(cprm, zeroes, nr);
}
- return ret;
}
-EXPORT_SYMBOL(dump_seek);
+EXPORT_SYMBOL(dump_skip);
+
+int dump_align(struct coredump_params *cprm, int align)
+{
+ unsigned mod = cprm->written & (align - 1);
+ if (align & (align - 1))
+ return 0;
+ return mod ? dump_skip(cprm, align - mod) : 1;
+}
+EXPORT_SYMBOL(dump_align);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 20:31:04 +0000