Re: The code segment of the user level in PPC64 are in VMAs with write permissions

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Dotan Barak a écrit :
Hi all.

I noticed that the code segment of the user level in PPC64 machines
is in a VMA with a write permission enabled.

I'm using the following machine attributes:
*************************************************************
Host Name         : mtlsqt185
Host Architecture : ppc64
Linux Distribution: SUSE Linux Enterprise Server 10 (ppc) VERSION = 10 PATCHLEVEL = 1
Kernel Version    : 2.6.16.53-0.16-ppc64
GCC Version       : gcc (GCC) 4.1.2 20070115 (prerelease) (SUSE Linux)
Memory size       : 1740232 kB
Number of CPUs    : 8
cpu MHz           : 4005.000000MHz
Driver Version    : OFED-1.2.5.4-20071210-0614
HCA ID(s)         : mlx4_0
HCA model(s)      : 25418
FW version(s)     : 2.3.906
Board(s)          : IBM08A0000001
*************************************************************

I printed the address of a function in my program and i got the value 0x1005ac80.

I printed the VMAs in my process and i got the following output:
mtlsqt185:~ # cat /proc/17366/maps
00100000-00103000 r-xp 00100000 00:00 0
10000000-1004a000 r-xp 00000000 08:03 1063667 /tmp/tsscr/svn.mlx_tp/branches/ofed1.2.5/gen2/userspace/useraccess/gen2_basic/gen2_basic 1005a000-1005e000 rw-p 0004a000 08:03 1063667 /tmp/tsscr/svn.mlx_tp/branches/ofed1.2.5/gen2/userspace/useraccess/gen2_basic/gen2_basic 1005e000-1015f000 rw-p 1005e000 00:00 0 [heap]

Is this is a security hole (any virus can change the code in the code segment ...)

can you please CC me the answers o this question?


This is because on PPC architecture, address of a function points to a small
data area (a function descriptor) where the caller can find informations about :

- Address (in the text segment, so readonly) of the target function
- Address of the TOC for this function.


http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#FUNC-ADDRESS
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux