lkml.org 
[lkml]   [2016]   [Feb]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.13.y-ckt 076/136] sparc64: fix incorrect sign extension in sys_sparc64_personality
    Date
    3.13.11-ckt34 -stable review patch.  If anyone has any objections, please let me know.

    ---8<------------------------------------------------------------

    From: "Dmitry V. Levin" <ldv@altlinux.org>

    commit 525fd5a94e1be0776fa652df5c687697db508c91 upstream.

    The value returned by sys_personality has type "long int".
    It is saved to a variable of type "int", which is not a problem
    yet because the type of task_struct->pesonality is "unsigned int".
    The problem is the sign extension from "int" to "long int"
    that happens on return from sys_sparc64_personality.

    For example, a userspace call personality((unsigned) -EINVAL) will
    result to any subsequent personality call, including absolutely
    harmless read-only personality(0xffffffff) call, failing with
    errno set to EINVAL.

    Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    arch/sparc/kernel/sys_sparc_64.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
    index 25db14a..47ae8d7 100644
    --- a/arch/sparc/kernel/sys_sparc_64.c
    +++ b/arch/sparc/kernel/sys_sparc_64.c
    @@ -412,7 +412,7 @@ out:

    SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality)
    {
    - int ret;
    + long ret;

    if (personality(current->personality) == PER_LINUX32 &&
    personality(personality) == PER_LINUX)
    --
    1.9.1
    \
     
     \ /
      Last update: 2016-02-02 20:21    [W:2.585 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site