Messages in this thread | | | Date | Fri, 6 Jun 2014 14:56:05 +0800 | From | WANG Chao <> | Subject | Re: [PATCH 07/13] kexec: Implementation of new syscall kexec_file_load |
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On 06/03/14 at 09:06am, Vivek Goyal wrote: > Previous patch provided the interface definition and this patch prvides > implementation of new syscall. > > Previously segment list was prepared in user space. Now user space just > passes kernel fd, initrd fd and command line and kernel will create a > segment list internally. > > This patch contains generic part of the code. Actual segment preparation > and loading is done by arch and image specific loader. Which comes in > next patch. > > Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
[..] > diff --git a/kernel/kexec.c b/kernel/kexec.c > index a3044e6..1ad4d60 100644 > --- a/kernel/kexec.c > +++ b/kernel/kexec.c
> +static int kimage_file_prepare_segments(struct kimage *image, int kernel_fd, > + int initrd_fd, const char __user *cmdline_ptr, > + unsigned long cmdline_len) > +{ > + int ret = 0; > + void *ldata; > + > + ret = copy_file_from_fd(kernel_fd, &image->kernel_buf, > + &image->kernel_buf_len); > + if (ret) > + return ret; > + > + /* Call arch image probe handlers */ > + ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, > + image->kernel_buf_len); > + > + if (ret) > + goto out; > + > + ret = copy_file_from_fd(initrd_fd, &image->initrd_buf, > + &image->initrd_buf_len); > + if (ret) > + goto out; > + > + image->cmdline_buf = vzalloc(cmdline_len);
You should validate the upper/lower boundary of cmdline_len before calling vzalloc. When cmdline_len is 0 or too large, vmalloc failure message would be fired.
> + if (!image->cmdline_buf) > + goto out; > + > + ret = copy_from_user(image->cmdline_buf, cmdline_ptr, cmdline_len); > + if (ret) { > + ret = -EFAULT; > + goto out; > + } > + > + image->cmdline_buf_len = cmdline_len; > + > + /* command line should be a string with last byte null */ > + if (image->cmdline_buf[cmdline_len - 1] != '\0') { > + ret = -EINVAL; > + goto out; > + }
Given the fact that command line is optional as well as initrd, I think above chunk of code needs to update a bit for the case cmdline_len is 0 or cmdline_buf is pointing NULL?
Thanks WANG Chao
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