From 0eead9ab41da33644ae2c97c57ad03da636a0422 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 14 Oct 2010 10:57:40 -0700
Subject: [PATCH] Don't dump task struct in a.out core-dumps
akiphie points out that a.out core-dumps have that odd task struct
dumping that was never used and was never really a good idea (it goes
back into the mists of history, probably the original core-dumping
code). Just remove it.
Also do the access_ok() check on dump_write(). It probably doesn't
matter (since normal filesystems all seem to do it anyway), but he
points out that it's normally done by the VFS layer, so ...
[ I suspect that we should possibly do "vfs_write()" instead of
calling ->write directly. That also does the whole fsnotify and write
statistics thing, which may or may not be a good idea. ]
And just to be anal, do this all for the x86-64 32-bit a.out emulation
code too, even though it's not enabled (and won't currently even
compile)
Reported-by: akiphie <akiphie@lavabit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/x86/ia32/ia32_aout.c | 22 +++++-----------------
fs/binfmt_aout.c | 4 ----
include/linux/coredump.h | 2 +-
3 files changed, 6 insertions(+), 22 deletions(-)
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index 0350311906ae7..2d93bdbc9ac02 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -34,7 +34,7 @@
#include <asm/ia32.h>
#undef WARN_OLD
-#undef CORE_DUMP /* probably broken */
+#undef CORE_DUMP /* definitely broken */
static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
static int load_aout_library(struct file *);
@@ -131,21 +131,15 @@ static void set_brk(unsigned long start, unsigned long end)
* macros to write out all the necessary info.
*/
-static int dump_write(struct file *file, const void *addr, int nr)
-{
- return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
-}
+#include <linux/coredump.h>
#define DUMP_WRITE(addr, nr) \
if (!dump_write(file, (void *)(addr), (nr))) \
goto end_coredump;
-#define DUMP_SEEK(offset) \
- if (file->f_op->llseek) { \
- if (file->f_op->llseek(file, (offset), 0) != (offset)) \
- goto end_coredump; \
- } else \
- file->f_pos = (offset)
+#define DUMP_SEEK(offset) \
+ if (!dump_seek(file, offset)) \
+ goto end_coredump;
#define START_DATA() (u.u_tsize << PAGE_SHIFT)
#define START_STACK(u) (u.start_stack)
@@ -217,12 +211,6 @@ static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
dump_size = dump.u_ssize << PAGE_SHIFT;
DUMP_WRITE(dump_start, dump_size);
}
- /*
- * Finally dump the task struct. Not be used by gdb, but
- * could be useful
- */
- set_fs(KERNEL_DS);
- DUMP_WRITE(current, sizeof(*current));
end_coredump:
set_fs(fs);
return has_dumped;
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index f96eff04e11ab..a6395bdb26aeb 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -134,10 +134,6 @@ static int aout_core_dump(struct coredump_params *cprm)
if (!dump_write(file, dump_start, dump_size))
goto end_coredump;
}
-/* Finally dump the task struct. Not be used by gdb, but could be useful */
- set_fs(KERNEL_DS);
- if (!dump_write(file, current, sizeof(*current)))
- goto end_coredump;
end_coredump:
set_fs(fs);
return has_dumped;
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index 8ba66a9d9022c..59579cfee6a08 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -11,7 +11,7 @@
*/
static inline int dump_write(struct file *file, const void *addr, int nr)
{
- return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+ return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}
static inline int dump_seek(struct file *file, loff_t off)
--
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