The patch titled powerpc: keep 3 high personality bytes across exec has been added to the -mm tree. Its filename is powerpc-keep-3-high-personality-bytes-across-exec.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: powerpc: keep 3 high personality bytes across exec From: Eric B Munson <ebmunson@xxxxxxxxxx> Currently when a 32 bit process is exec'd on a powerpc 64 bit host the value in the top three bytes of the personality is clobbered. This patch adds a check in the SET_PERSONALITY macro that will carry all the values in the top three bytes across the exec. These three bytes currently carry flags to disable address randomisation, limit the address space, force zeroing of an mmapped page, etc. Should an application set any of these bits they will be maintained and honoured on homogeneous environment but discarded and ignored on a heterogeneous environment. So if an application requires all mmapped pages to be initial= ised to zero and a wrapper is used to setup the personality and exec the target, these flags will remain set on an all 32 or all 64 bit envrionment, but they will be lost in the exec on a mixed 32/64 bit environment. Losing these bi= ts means that the same application would behave differently in different environments. Tested on a POWER5+ machine with 64bit kernel and a mixed 64/32 bit user space. Signed-off-by: Eric B Munson <ebmunson@xxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/asm-powerpc/elf.h | 3 ++- include/linux/personality.h | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff -puN include/asm-powerpc/elf.h~powerpc-keep-3-high-personality-bytes-across-exec include/asm-powerpc/elf.h --- a/include/asm-powerpc/elf.h~powerpc-keep-3-high-personality-bytes-across-exec +++ a/include/asm-powerpc/elf.h @@ -257,7 +257,8 @@ do { \ else \ clear_thread_flag(TIF_ABI_PENDING); \ if (personality(current->personality) != PER_LINUX32) \ - set_personality(PER_LINUX); \ + set_personality(PER_LINUX | \ + (current->personality & PER_INHERIT)); \ } while (0) /* * An executable for which elf_read_implies_exec() returns TRUE will diff -puN include/linux/personality.h~powerpc-keep-3-high-personality-bytes-across-exec include/linux/personality.h --- a/include/linux/personality.h~powerpc-keep-3-high-personality-bytes-across-exec +++ a/include/linux/personality.h @@ -36,6 +36,12 @@ enum { ADDR_LIMIT_3GB = 0x8000000, }; +/* Mask for the above personality values */ +#define PER_INHERIT (ADDR_NO_RANDOMIZE|FDPIC_FUNCPTRS|MMAP_PAGE_ZERO| \ + ADDR_COMPAT_LAYOUT|READ_IMPLIES_EXEC|ADDR_LIMIT_32BIT| \ + SHORT_INODE|WHOLE_SECONDS|STICKY_TIMEOUTS| \ + ADDR_LIMIT_3GB) + /* * Security-relevant compatibility flags that must be * cleared upon setuid or setgid exec: _ Patches currently in -mm which might be from ebmunson@xxxxxxxxxx are powerpc-keep-3-high-personality-bytes-across-exec.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html