lkml.org 
[lkml]   [2018]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 035/159] netfilter: x_tables: fix int overflow in xt_alloc_table_info()
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Dmitry Vyukov <dvyukov@google.com>

    commit 889c604fd0b5f6d3b8694ade229ee44124de1127 upstream.

    syzkaller triggered OOM kills by passing ipt_replace.size = -1
    to IPT_SO_SET_REPLACE. The root cause is that SMP_ALIGN() in
    xt_alloc_table_info() causes int overflow and the size check passes
    when it should not. SMP_ALIGN() is no longer needed leftover.

    Remove SMP_ALIGN() call in xt_alloc_table_info().

    Reported-by: syzbot+4396883fa8c4f64e0175@syzkaller.appspotmail.com
    Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    net/netfilter/x_tables.c | 3 +--
    1 file changed, 1 insertion(+), 2 deletions(-)

    --- a/net/netfilter/x_tables.c
    +++ b/net/netfilter/x_tables.c
    @@ -39,7 +39,6 @@ MODULE_LICENSE("GPL");
    MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
    MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");

    -#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
    #define XT_PCPU_BLOCK_SIZE 4096

    struct compat_delta {
    @@ -1000,7 +999,7 @@ struct xt_table_info *xt_alloc_table_inf
    return NULL;

    /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
    - if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
    + if ((size >> PAGE_SHIFT) + 2 > totalram_pages)
    return NULL;

    info = kvmalloc(sz, GFP_KERNEL);

    \
     
     \ /
      Last update: 2018-02-23 20:29    [W:4.026 / U:0.376 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site