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coredump: kill cn_escape(), introduce cn_esc_printf()

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The usage of cn_escape() looks really annoying, imho this sequence needs a
wrapper.  And it is buggy.  If cn_printf() does expand_corename()
cn_escape() writes to the freed memory.

Introduce cn_esc_printf() which hopefully does this all right.  It records
the index before cn_vprintf(), not "char *" which is no longer valid (in
general) after krealloc().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Colin Walters <walters@verbum.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov
2013-07-03 15:08:20 -07:00
committed by Linus Torvalds
parent 5fe9d8ca21
commit 923bed030f
1 changed files with 21 additions and 23 deletions
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44
fs/coredump.c
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@@ -99,11 +99,21 @@ static int cn_printf(struct core_name *cn, const char *fmt, ...)
return ret; return ret;
} }
static void cn_escape(char *str) static int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
{ {
for (; *str; str++) int cur = cn->used;
if (*str == '/') va_list arg;
*str = '!'; int ret;
va_start(arg, fmt);
ret = cn_vprintf(cn, fmt, arg);
va_end(arg);
for (; cur < cn->used; ++cur) {
if (cn->corename[cur] == '/')
cn->corename[cur] = '!';
}
return ret;
} }
static int cn_print_exe_file(struct core_name *cn) static int cn_print_exe_file(struct core_name *cn)
@@ -113,12 +123,8 @@ static int cn_print_exe_file(struct core_name *cn)
int ret; int ret;
exe_file = get_mm_exe_file(current->mm); exe_file = get_mm_exe_file(current->mm);
if (!exe_file) { if (!exe_file)
char *commstart = cn->corename + cn->used; return cn_esc_printf(cn, "%s (path unknown)", current->comm);
ret = cn_printf(cn, "%s (path unknown)", current->comm);
cn_escape(commstart);
return ret;
}
pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
if (!pathbuf) { if (!pathbuf) {
@@ -132,9 +138,7 @@ static int cn_print_exe_file(struct core_name *cn)
goto free_buf; goto free_buf;
} }
cn_escape(path); ret = cn_esc_printf(cn, "%s", path);
ret = cn_printf(cn, "%s", path);
free_buf: free_buf:
kfree(pathbuf); kfree(pathbuf);
@@ -207,22 +211,16 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
break; break;
} }
/* hostname */ /* hostname */
case 'h': { case 'h':
char *namestart = cn->corename + cn->used;
down_read(&uts_sem); down_read(&uts_sem);
err = cn_printf(cn, "%s", err = cn_esc_printf(cn, "%s",
utsname()->nodename); utsname()->nodename);
up_read(&uts_sem); up_read(&uts_sem);
cn_escape(namestart);
break; break;
}
/* executable */ /* executable */
case 'e': { case 'e':
char *commstart = cn->corename + cn->used; err = cn_esc_printf(cn, "%s", current->comm);
err = cn_printf(cn, "%s", current->comm);
cn_escape(commstart);
break; break;
}
case 'E': case 'E':
err = cn_print_exe_file(cn); err = cn_print_exe_file(cn);
break; break;