From: Sasha Levin Date: Fri, 13 Jan 2012 01:17:40 +0000 (-0800) Subject: pipe: fail cleanly when root tries F_SETPIPE_SZ with big size X-Git-Tag: v3.3-rc1~81^2~81 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=2ccd4f4d4737b37e21dd92c8c584c23cd87740a2 pipe: fail cleanly when root tries F_SETPIPE_SZ with big size When a user with the CAP_SYS_RESOURCE cap tries to F_SETPIPE_SZ a pipe with size bigger than kmalloc() can alloc it spits out an ugly warning: ------------[ cut here ]------------ WARNING: at mm/page_alloc.c:2095 __alloc_pages_nodemask+0x5d3/0x7a0() Pid: 733, comm: a.out Not tainted 3.2.0-rc1+ #4 Call Trace: warn_slowpath_common+0x75/0xb0 warn_slowpath_null+0x15/0x20 __alloc_pages_nodemask+0x5d3/0x7a0 __get_free_pages+0x12/0x50 __kmalloc+0x12b/0x150 pipe_set_size+0x75/0x120 pipe_fcntl+0xf8/0x140 do_fcntl+0x2d4/0x410 sys_fcntl+0x66/0xa0 system_call_fastpath+0x16/0x1b ---[ end trace 432f702e6db7b5ee ]--- Instead, make kcalloc() handle the overflow case and fail quietly. [akpm@linux-foundation.org: switch to sizeof(*bufs) for 80-column niceness] Signed-off-by: Sasha Levin Cc: Alexander Viro Acked-by: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/pipe.c b/fs/pipe.c index f0e485d54e64..a932ced92a16 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1137,7 +1137,7 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) if (nr_pages < pipe->nrbufs) return -EBUSY; - bufs = kcalloc(nr_pages, sizeof(struct pipe_buffer), GFP_KERNEL); + bufs = kcalloc(nr_pages, sizeof(*bufs), GFP_KERNEL | __GFP_NOWARN); if (unlikely(!bufs)) return -ENOMEM;