android_kernel_samsung_univ.../include/linux/magic.h
Eric Sandeen 7c9f8861e6 stackprotector: use canary at end of stack to indicate overruns at oops time
(Updated with a common max-stack-used checker that knows about
the canary, as suggested by Joe Perches)

Use a canary at the end of the stack to clearly indicate
at oops time whether the stack has ever overflowed.

This is a very simple implementation with a couple of
drawbacks:

1) a thread may legitimately use exactly up to the last
   word on the stack

 -- but the chances of doing this and then oopsing later seem slim

2) it's possible that the stack usage isn't dense enough
   that the canary location could get skipped over

 -- but the worst that happens is that we don't flag the overrun
 -- though this happens fairly often in my testing :(

With the code in place, an intentionally-bloated stack oops might
do:

BUG: unable to handle kernel paging request at ffff8103f84cc680
IP: [<ffffffff810253df>] update_curr+0x9a/0xa8
PGD 8063 PUD 0
Thread overran stack or stack corrupted
Oops: 0000 [1] SMP
CPU 0
...

... unless the stack overrun is so bad that it corrupts some other
thread.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-26 16:15:33 +02:00

47 lines
1.6 KiB
C

#ifndef __LINUX_MAGIC_H__
#define __LINUX_MAGIC_H__
#define ADFS_SUPER_MAGIC 0xadf5
#define AFFS_SUPER_MAGIC 0xadff
#define AFS_SUPER_MAGIC 0x5346414F
#define AUTOFS_SUPER_MAGIC 0x0187
#define CODA_SUPER_MAGIC 0x73757245
#define EFS_SUPER_MAGIC 0x414A53
#define EXT2_SUPER_MAGIC 0xEF53
#define EXT3_SUPER_MAGIC 0xEF53
#define EXT4_SUPER_MAGIC 0xEF53
#define HPFS_SUPER_MAGIC 0xf995e849
#define ISOFS_SUPER_MAGIC 0x9660
#define JFFS2_SUPER_MAGIC 0x72b6
#define ANON_INODE_FS_MAGIC 0x09041934
#define MINIX_SUPER_MAGIC 0x137F /* original minix fs */
#define MINIX_SUPER_MAGIC2 0x138F /* minix fs, 30 char names */
#define MINIX2_SUPER_MAGIC 0x2468 /* minix V2 fs */
#define MINIX2_SUPER_MAGIC2 0x2478 /* minix V2 fs, 30 char names */
#define MINIX3_SUPER_MAGIC 0x4d5a /* minix V3 fs */
#define MSDOS_SUPER_MAGIC 0x4d44 /* MD */
#define NCP_SUPER_MAGIC 0x564c /* Guess, what 0x564c is :-) */
#define NFS_SUPER_MAGIC 0x6969
#define OPENPROM_SUPER_MAGIC 0x9fa1
#define PROC_SUPER_MAGIC 0x9fa0
#define QNX4_SUPER_MAGIC 0x002f /* qnx4 fs detection */
#define REISERFS_SUPER_MAGIC 0x52654973 /* used by gcc */
/* used by file system utilities that
look at the superblock, etc. */
#define REISERFS_SUPER_MAGIC_STRING "ReIsErFs"
#define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs"
#define REISER2FS_JR_SUPER_MAGIC_STRING "ReIsEr3Fs"
#define SMB_SUPER_MAGIC 0x517B
#define USBDEVICE_SUPER_MAGIC 0x9fa2
#define CGROUP_SUPER_MAGIC 0x27e0eb
#define FUTEXFS_SUPER_MAGIC 0xBAD1DEA
#define INOTIFYFS_SUPER_MAGIC 0x2BAD1DEA
#define STACK_END_MAGIC 0x57AC6E9D
#endif /* __LINUX_MAGIC_H__ */